The State of Linux on My Chuwi Hi12 - October 2016

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NOTE: Gearbest is running a sale on many of their 2-in-1 Intel tablets on March 14 through March 18.

I knew running Linux on my Chuwi Hi12 tablet would be a challenge. I did my research before ordering the Chuwi tablet, and things weren’t looking too promising when my tablet arrived at my door early in August.

Most Linux distros would boot up just fine, but most of the hardware that makes my convertible Chuwi Hi12 tablet interesting just didn’t work yet. The touchscreen didn’t work. The Wi-Fi didn’t work. The sound didn’t work.

Chuwi Hi12 Running Xubuntu 16.10

Even back then, I think you could shoehorn in a working Wi-Fi driver. That would at least leave you with a functional laptop. I didn’t buy a laptop. I bought a tablet, and a tablet without a touchscreen isn’t much of a tablet.

Too long; didn’t read!

I’ll talk about most of this at length, but I’m sure most of you are just here for the highlights.

What works:

  • GPU / Display / Manual rotation
  • HDMI Audio (untested)
  • Touchscreen
  • Keyboard dock and touchpad
  • MicroSD slot
  • USB ports
  • Lid sensor
  • Wi-Fi
  • Active Stylus

What doesn’t work:

  • Sound
  • Cameras
  • Accelerometer
  • Bluetooth (untested)
  • Suspend / Resume
  • Power and volume buttons
  • Battery and AC status
  • MicroSD slot

Other problems:

  • eats CPU after manual screen rotation (XFCE problem?)
  • Goodix touchscreen module sometimes needs to be unloaded and reloaded at boot

Wi-Fi and HDMI audio don’t work out of the box on Ubuntu 16.10. The power button was working when I installed Xubuntu 16.10, but it isn’t anymore. I haven’t figured out what change caused it to stop functioning.

UPDATE: My power and volume buttons are being recognized once again. I caused the problem by unloading and reloading the Goodix touchscreen kernel module. I was able to correct the problem by adding a delay before reloading the module. This is an odd problem, but at least it works!

UPDATE: Using a MicroSD card has been problematic, and it seems to have gotten worse over time. It got to the point where there was less than a 50% chance of my SD card working on each reboot. I decided to wipe out Windows 10 and move my home directory to the built-in flash. Since this change, I have been able to suspend and resume over and over again without any issues.

What works on Linux?

Ubuntu 16.10 has made a lot of progress. The touchscreen works—most of the time. Sometimes I need to rmmod and modprobe the goodix module when the tablet boots up. That was simple enough to automate at each reboot!

The GPU works fine, and the 2160x1440 display is detected automatically. The dock’s keyboard and touchpad work as expected. The USB ports work, and the Micro-SD reader functions correctly most of the time. I have my home directory on an SD card, and I have managed to lock up the tablet by hammering on it hard enough. The Micro-SD reader has been acting flakier and flakier. I finally ended up wiping the Windows 10 partition, and for the time being I won’t be using the SD card.

I had to compile a new Wi-Fi driver for the rtl8723bs chip. You can clone the driver from GitHub and compile it yourself. The directions are quite clear, but if you aren’t comfortable with this sort of thing, you should check out the builds from Linuxium. They have Ubuntu install media that includes their patched kernel, or you can just install their kernel on your existing Ubuntu installation.

You also have to change the mode of the Wi-Fi chip to PCI. It can be found in the BIOS under Chipset -> South Bridge -> LPSS & SCC Configuration -> SSC SDIO Support.

Chuwi Hi12 BIOS

The Chuwi HiPen is mostly functional. It works as a high-accuracy pointing device, and the edge of my palm doesn’t trigger the touch screen. However, the buttons don’t seem to trigger any events.

UPDATE: I installed the latest kernel from Linuxium. Sound doesn’t work yet, but it is able to read the charge of my battery. This is a HUGE improvement for me. I no longer need to plug in when I’m worried that I MIGHT be running low on charge!

What doesn’t work on Linux?

There’s quite a bit of important stuff that doesn’t work on Linux yet. The most important missing feature for me is sound. The Linuxium kernel is patched to support sound over HDMI, but there is currently no support for the on-board Intel sound chip. The Chuwi Hi12 and Chuwi Hi10 both use the same sound chip as the Surface 3, and work seems to be progressing there. I hope that work will spill over to our inexpensive tablet soon!

Neither of the cameras work. I don’t find that to be a big loss; I don’t use them anyway.

Suspend and resume is flaky. I can resume from suspend successfully once. If I suspend a second time, I can’t get the Chuwi Hi12 to wake up. This wouldn’t bother me much on a laptop, but it is an extreme annoyance on a tablet.

If I’m not using a MicroSD card, then suspend and resume works somewhat reliably.

AmazonBasics 11.6 inch bag

The accelerometer doesn’t work yet. I believe a driver exists, but it doesn’t work yet. I set up a simple script that watches for the keyboard dock. If the tablet is in the dock, I force the screen to landscape mode. When the tablet is removed from the dock, it switches to portrait. This isn’t an ideal solution, but it has me covered 99% of the time.

Unfortunately, once the screen is rotated, runs away and consumes tons of CPU. It doesn’t noticeably impact performance, but I bet it is eating up my battery.

Speaking of battery, Linux can’t yet read the charge state of the battery. I have no idea how much juice is remaining, so I’ve been making it a habit to plug in whenever I can.

You can now see the current charge state of your battery if you’re running the Linuxium 4.10 kernel!

Hacking around the lack of accelerometer

I added a udev rule to create a symlink called keyboard_dock when the Chuwi Hi12 is plugged into the keyboard dock. This gives my little daemon script something to watch for.

ACTION=="add", ATTRS{idVendor}=="258a", ATTRS{idProduct}=="6a88", SYMLINK+="keyboard_dock"

Here is my kludge of a daemon script. It uses inotify to watch the /dev/ directory. When the keyboard dock changes state, it rotates the display and touch screen. It also reloads my xmodmap configuration, because it seems to be lost every time the keyboard is plugged back in.
#! /bin/zsh

while true; do
  if [[ -e /dev/keyboard_dock ]]; then
    xrandr -o normal
    xinput set-prop 11 "Evdev Axes Swap" 0
    xinput set-prop 11 "Evdev Axis Inversion" 0, 0
    xmodmap ~/.Xmodmap
    xrandr -o left
    xinput set-prop 11 "Evdev Axes Swap" 1
    xinput set-prop 11 "Evdev Axis Inversion" 1, 0
    xmodmap ~/.Xmodmap

  inotifywait  /dev --excludei '^[a-jl-z0-9]'
  sleep 1;

Would I be better off running Windows?

It is a close call, but I am already slightly better off running Linux full time on my Chuwi Hi12 for my purposes. Having a proper terminal emulator with a first-class UNIX shell environment is so much more useful to me than the “Bash on Ubuntu on Windows” nonsense, and being able to use a good window manager to wrangle all my terminal windows is much more comfortable.

Two of our Chuwi Hi12 laptops

It has been over a week since I last booted Windows 10, and I’m confident that I won’t be booting it again. The lack of audio on Linux is probably my biggest nuisance at the moment, but I’ve really only missed it once or twice.

For now, though, I have a working web browser, a better Emacs experience, and I spend less time managing windows. And on top of that, everything on my Chuwi now looks and feels just like my Linux laptop and desktop.

Everything works just well enough to keep me from wanting to boot into Windows, and I’m hopeful that things will continue to improve in the future!

You can use the Gearbest coupon codes to save yourself a few dollars.

My Chuwi Hi12 - Two Months Later

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NOTE: Gearbest is running a sale on many of their 2-in-1 Intel tablets on March 14 through March 18.

I’ve had my Chuwi Hi12 for more than two months now. I’ve used it every single day. It has become an essential part of my daily workflow at home, and I take it with me almost every time I leave the house.

Chuwi Hi12 HiPen Active Stylus Pen

My friends at Gearbest sent me a Chuwi HiPen stylus to try out, so I thought this would be a good time to post an update on how things are going with the Chuwi.

All three Chuwi Hi12 tablets are doing fine!

We currently have a trio of Chuwi Hi12 tablets in the family. I have one, my wife has one, and my father-in-law has one. They’re all still working and used on a regular basis. Mine sees more use than the other two, but my wife brings her Chuwi every time she visits makerspace.

Two Out of Our Three Chuwi Hi12 Tablets

I ended up taking off the plastic screen protector from my Chuwi during its first month of service. Since it doesn’t have Corning Gorilla glass, I was worried that I’d end up scratching the screen. I’ve never scratched a plastic laptop screen, and the screen on my Chuwi is still unscratched, so I’m not too worried about it.

My fingers glide much more smoothly across the glass. The touch screen also seems more responsive now, especially when it is wobbling slightly in the keyboard dock.

I dropped my Chuwi Hi12

I’ve had a laptop in my possession continuously for almost 20 years now. Before owning the Chuwi, I had only dropped a laptop once. I believe my Fujitsu P2120 ended up tipping off the night stand. It suffered a minor cosmetic injury, and if I remember the incident correctly, it wasn’t entirely my fault.

When I dropped the Chuwi, it was my fault. I was carrying it around like an open laptop, and I set it down on top of one of our FlashForge Creator Pro 3D printers at Had it been a real laptop, this would have been fine.

If you’ve ever seen the acrylic tent on top of a FlashForge Creator Pro, you can probably already guess what happened. The edges of the tent are a good bit higher than the center. This pushed the Chuwi tablet up and out of its dock, and it tumbled onto the desk behind the printer.

Other than a tiny scuff mark on its metal shell, everything is fine.

The Chuwi Handwriting Pen

Gearbest asked me if I’d like to try out the active stylus pen for the Chuwi Hi12, and I have to say I was excited to give it a try. There was a good chance it would address one of the biggest failings of my Windows 10 tablet experience.

I have over 900 games in my Steam library. Quite a few of those games started life as mobile games, and some of the native PC games now have mobile ports. Almost every one that I wanted to play in tablet mode can’t be played without a mouse. They either need a way to efficiently click the right mouse button, or they need the middle mouse button. The pen almost solves the first problem, but doesn’t address the second.

Chuwi Hi12 HiPen Active Stylus Pen

I was looking forward to playing Prison Architect on a giant tablet, but Prison Architect uses the middle mouse button to scroll. When I eventually get Linux working on the Chuwi, I’ll definitely be able to address this issue, and I’m certain I’ll be playing Prison Architect with pen.

One of the best games I tried with the active pen so far is Torchlight 2. It runs well enough on the Chwui Hi12, and the controls work great. After playing for a few minutes with the pen, though, I learned that it is more comfortable to play with my fingers.

Torchlight 2 on The Chuwi Hi12 Tablet

The pen hardware is fantastic. It is a metal pen with a reasonable amount of heft to it—not ridiculously heavy, but it doesn’t feel like a disposable Bic. It is pressure sensitive and extremely accurate.

I am a big fan of whiteboards. Using my tablet in place of one seemed like it would be fun, so I sketched a few things using Microsoft OneNote. It is rare that you’ll hear me say nice things about Microsoft’s products, but OneNote has a feature that I haven’t had since my Palm Treo 650. It has an option that lets you draw sloppy geometric shapes, and it converts them into clean polygons.

I haven’t had to work on anything yet that requires a sketch, but I’m looking forward to the day when I get to exclaim, “Wait a minute! I’ll get my stylus!” with great anticipation.

Gearbest gave me a coupon code (GBHSP) for the Active Stylus Pen. It looks like it will get you the Chuwi Hipen H1 for $14.99 with free shipping.

Linux on the Chuwi Hi12

I’m not running Linux on my Chuwi just yet, but I’m getting closer. I expect I’ll be wiping Windows 10 off the Chuwi shortly after Ubuntu 16.10 is released. I booted a few live Linux distros, and my findings are quite promising.

I was able to compile a working Goodix touchscreen driver from GitHub. I didn’t have success at first, but there’s a rather large bug in the “working” Goodix driver. It doesn’t work after a cold boot. The touchscreen always seems to work fine on the second boot. If I can’t fix this, it will be annoying, but it won’t be a show stopper.

Xubuntu Booting On The Chuwi Hi12

I booted a strange, scary, Cherry Trail oriented Ubuntu derivative. It had a working driver for the Chuwi Hi12’s rtl8723bs Wi-Fi chipset.

Sound didn’t work on either of the Linux distros I tested. lspci shows the same multimedia controller as the Microsoft Surface 3, but ALSA doesn’t see anything. The Surface 3 is currently in the same boat, so I’m hopeful that the Chuwi will make progress here soon.

I was able to suspend and resume the tablet several times without issue.

I didn’t think to test the cameras—I don’t care if they work. It will be annoying to not have working audio, but it will be less annoying and embarrassing than using Windows 10.

How have I been using the Chuwi Hi12?

I intended for my Chwui Hi12 to take the place of both my giant 18.4” laptop and my 8.3” Android tablet. There are still situations where my aging desktop-replacement laptop is a much more suitable tool than the Chuwi, but those situations haven’t come up often. In fact, I’ve only taken my old HP laptop with me once since my tablet arrived.

At home, I use the Chuwi in tablet mode to read through my email, RSS feeds, Twitter, and Reddit. I usually do this from the recliner in my office or in the living room. I might peck out an occasional tweet with the on-screen keyboard, but if I have to respond to an email, I’ll drop the Chuwi into the keyboard dock.

AmazonBasics 11.6-inch Laptop Bag

As I expected, my Chuwi tablet spends most of its time docked in the keyboard. I’ve had lots of better laptop keyboards than the Chuwi Hi12 dock, but I’ve had a few worse, too. It gets the job done, but when I’m typing fast, it often misses my shift key and I end up missing capital letters. It works fine if I slow down a little, so I imagine most people don’t notice this.

I use the Chuwi as a laptop much more often than as a tablet. There are a lot of reasonably priced ultrabooks that are lighter and much faster than my Chuwi Hi12, and sometimes I wonder if that’s the route I should have gone. The Xiaomi Air 12 is small, light, and inexpensive. It’s also a bit faster than my old laptop.

I may only do it once or twice a day, but being able to ditch the keyboard and relax is a great feature. If I were using a standard ultrabook instead, I’d miss the tablet. Especially away from home, where I wouldn’t be likely to have both a laptop and tablet available.

The Chuwi Hi12 is powerful enough for the tasks I do when I’m not in my home office. I can comfortably surf the web, check email and Twitter, and write blog posts using Emacs. I can even edit RAW photos from my DSLR, though I’d prefer to wait until I get home—the Chuwi just feels too slow when using Darktable!

I had trouble with the keyboard, and it was all my fault!

For quite a few days, my Chuwi wasn’t making a good connection to the keyboard dock. When it was in my lap, it would disconnect and reconnect every time I’d fidget a bit. It even had trouble on my desk if I used the touch screen while it was docked in the keyboard. I thought for certain that there was something wrong with the Pogo pins.

The problem was much simpler than that. The connectors were just dirty. I’ve been telling everyone that I must have been eating while holding the tablet, and I got some pizza on the connector. It wasn’t visibly dirty, though, so I don’t know what actually got on there. I only know that cleaning it with my screen cleaner, aka rubbing alcohol, took care of the problem.

I’m still going to claim that the problem was caused by pizza.

Charging the Chuwi and USB battery packs

The Chuwi Hi12’s battery lasts a long time. I used it for several hours each day, and it rarely has less than 50% charge when I plug it in at the end of the day. I know it’ll manage to run for more than 6 hours with the screen at 50% brightness, and dropping that down to 25% probably extends the run time by nearly 2 hours. 50% brightness is too bright in a dimly lit room, while 25% is just about right.

The Chuwi Hi12 charges quite slowly. I tested a lot of USB cables. Even with my biggest 3A USB wall charger and my best Volutz Micro USB cable, it still takes forever to charge. How long is forever? I’ve never had the patience to measure, since it usually tops off over night. I do know that when I’m down below 30%, Windows 10 estimates that it will take over four hours to charge. This is the disadvantage of charging using Micro USB.

There is an advantage, though. I can run my laptop using USB battery packs. My oldest, smallest battery pack can only put out about 500 mA. That’s not enough to charge the Chuwi, but it does slow down the draining of the Chuwi’s battery.

Kmashi and RAVPower USB Battery Packs

The battery pack I carry in my laptop bag is a RAVPower Wi-Fi router with a 6,000 mAh battery built in. It can put out about 1,000 mA. That’s not enough to charge the laptop while it is running, but it is enough to keep the laptop battery from discharging. It can run the laptop for 3.5 hours.

I have a 15,000 mAh Kmashi battery pack. I wouldn’t be surprised if it ran the Chuwi for over 10 hours. I certainly don’t have the patience to find out!

I did encounter a small peculiarity during testing these USB batteries. When the battery gets close to dying, the Chuwi Hi12 would usually power off. I’m assuming Chuwi skimped somewhere in their charging circuitry, and it doesn’t always manage to switch over to the internal battery when the voltage on the USB power drops.

It is a minor problem, but that doesn’t make it any less strange.

The verdict

I’ve been using the Chuwi Hi12 for more than two months, and I won’t be surprised if I’m still using it twelve months from now. For my use case, it is just fast enough, just light enough, and you just can’t beat the price. It is a great piece of hardware for the price, especially when you can get the Chuwi Hi12 tablet and keyboard from for less than $300. It isn’t priced that low every day, but it seems to be on sale more often than not.

My Little Drawing With The Chuwi HiPen Active Stylus

I’m enjoying the Chuwi HiPen, too, and I suspect I’ll use it more and more as time goes on. For my purposes, I don’t think I’d pay the $40 that Amazon is asking for the pen, but with the coupon code (GBHSP) at, you can get it for $15 shipped. That’s a much better value.

If you need a laptop for light duties, and you have a workload like me, I highly recommend the Chuwi Hi12. The versatility and build quality are amazing, and it is hard to beat the Hi12’s beautiful 12” 2160x1440 display. There’s just nothing comparable at this price point.

You can save almost $100 if you go with the smaller Chwui Hi10. Aside from the smaller display, the Chuwi Hi10 is almost identical to the Chuwi Hi12. If you don’t need the larger, higher-resolution screen, then the Chuwi Hi10 may be a better choice. I think the screen on the Hi12 is well worth the extra $100.

You can use the coupon codes to save yourself a few dollars.

The Chuwi Hi12 Tablet and Keyboard

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NOTE: Gearbest is running a sale on many of their 2-in-1 Intel tablets on March 14 through March 18.

I’ve been using the same laptop for more than six years. It is a giant laptop with an 18.4” screen, and it weighs nearly ten pounds. When I bought it, it was a desktop replacement, and its quad core i7 processor is still just as fast as any of the ultrabooks I’ve been interested in—like my friend Brian’s Dell XPS 13.

My Fujitsu P2120 Posing With My Chuwi Hi12

The big laptop is nice when I travel, because I often end up setting it up on a desk somewhere at my destination, and it sits there for most of the duration of my trip. Lately, though, I’ve been lugging my heavy laptop bag to makerspace several times each week, so I’ve been feeling the need for a more portable laptop.

More than a decade ago, I owned a Fujitsu P2120. It was an expensive, business-grade, netbook-size laptop from the days before inexpensive netbooks even existed. It was small, light, and it would run for 10 hours on a single charge. I was hoping to recreate that experience with modern hardware, and without spending $2,500 like I did in 2003.

In the size and weight range I was interested in, there are quite a few tablets with keyboards and kickstands—like the HP Spectre x2 and Surface Pro 3—but I don’t like these kickstands. I wanted something that I could comfortably use in my lap. I don’t want to skip ahead too far, but I’m writing this blog post in my office while sitting in my big recliner with my Chuwi Hi12 on my lap.

I had quite a few requirements on my wishlist, and the Chuwi Hi12 did a good job of meeting most of them.

  • 12” or 13” screen
  • Tablet with a keyboard dock
  • No kickstands!
  • x86 CPU
  • As much RAM as possible
  • Linux support

What else did I look at besides the Chuwi Hi12?

One of the most obvious choices is the Surface Pro 3. Although it is a nice piece of hardware, it starts at closer to $900—three times more than I paid for my Chuwi Hi12—and the odds of ever running Linux on the Surface seem pretty low. I’d be willing to pay $1,000 or more for a higher-end device, but not if I’m stuck running Windows 10.

The HP Spectre x2 looks like a decent piece of hardware, and it sure looks like it should be easy enough to get Ubuntu running on it. Unfortunately, the Spectre is another tablet with a kickstand and a flappy keyboard.

  Chuwi Hi12 Surface Pro 3 Dell XPS 13 ASUS Chromebook
RAM 4 GB 4 GB 8 GB 4 GB
CPU Atom Z8300 i3-4020Y(?) i5-6200u Dual Core 2.16 Ghz
Storage 64 GB 128 GB 128 GB 16 GB
Display 12.2”
Tablet Weight 1.88 lbs 1.76 lbs n/a n/a
Keyboard Weight 1.88 lbs 0.58 lbs n/a n/a
Total Weight 3.76 lbs 2.34 lbs 2.6 lbs 3.1 lbs
Price $280 to $380 $800 $869 $270

On the more inexpensive end, I looked at some of the Asus Transformer tablets. ASUS actually has tablets with keyboard docks similar to the Chuwi Hi12. They just don’t quite meet the specs of the Chuwi. The most reasonably priced Transformer tablets have less RAM than the Chuwi, and the 12” Transformers have smaller, low resolution, 16:9 aspect ratio screens.

I also looked at some Chromebooks. They don’t exactly meet my needs, but they are at least light and inexpensive. I included one in my features table for the sake of completeness.

Let’s talk about the Chuwi Hi12

The Chuwi Hi12 is a compromise, but I can definitely say that it is an interesting compromise. It is easy to compare it to the Surface Pro 3 and dismiss the Chuwi Hi12 because of its underpowered processor. I don’t look at it this way.

The Chuwi Hi12 is priced competitively with 13-inch Chromebooks, but the Chuwi has a full operating system, the same beautiful screen as the Surface Pro 3, and it is a 2-in-1 tablet to boot. It is a fantastic piece of hardware for this price point!

Surface Pro 3 Next To My Chuwi Hi12

The keyboard really sealed the deal for me—especially if you get the new version of the Chuwi Hi12 keyboard. I only had my Chuwi Hi12 for a couple of days before we had to order one for my wife. Hers came with a different keyboard—one I hadn’t seen in any reviews yet.

My older Chuwi keyboard has a narrow touchpad. The newer model has pushed the keys closer to the screen to make room for a regular-size touchpad, and in doing so they also created a more comfortable area to rest your wrists. The keys on the new-style keyboard feel a little better, and it is slightly thinner than the original, but it makes more noise when I type.

I read quite a few reviews before purchasing our first Chuwi Hi12. Most of them agreed that the keyboard is excellent, while the touchpad is garbage. I’m not a fan of any touchpad, but they’re correct—that narrow touchpad on the original keyboard is pretty crummy. The new touchpad is a huge improvement.

The Chuwi Hi12 keyboard closely matches the dimensions of my IBM Model M keyboard.

I’m embarrassed to be running Windows 10

I haven’t had Windows on any of my home computers since the days when I dual booted Windows 95 on my old Cyrix P200. I actually avoided the Chuwi Hi12 for months because I wasn’t interested in carrying a Windows laptop.

I’m treating this more like an appliance—a web-browsing machine that happens to run Emacs. I hope it won’t be too many months before I can switch to Linux. It sounds like Ubuntu boots just fine, but the drivers for the touch screen, accelerometer, and sound card aren’t working correctly.

For now, I’m just pleased that I don’t have to carry a 10-pound laptop, and an even heavier bag.

Upgrade the video driver!

Shortly after Windows 10 downloaded and installed the first batch of updates, my Chuwi tablet was crashing a lot. Almost every time it crashed was after putting it to sleep. I updated the Intel video driver, and it hasn’t been a problem since.

Just how heavy is the Chuwi Hi12?

At about 1.8 pounds, the Chuwi Hi12 tablet isn’t more than a few ounces heavier than the Surface Pro 3, but the keyboard is a different story. My friend Sam carries a Surface Pro 3, and when I handed him the folded-up Chuwi Hi12, he just said it was way too heavy!

Two Chuwi Hi12 Tablets With The New And Old Keyboard Dock

I expected this would be the case, and it is a trade-off I’m more than happy to make. The Chuwi keyboard has to have some mass to it, or else the weight of the tablet would make it unstable in “laptop mode.” I’m willing to carry a little extra weight, especially if it means I can easily use my laptop in my lap.

The tablet-and-keyboard combo weighs a total of 3.5 pounds. That’s less than a pound heavier than my friend Brian’s Dell XPS 13. Speaking of the XPS 13, if you’ve seen one, you know roughly how big the Chuwi Hi12 is. Brian’s laptop is a hair thinner than my folded up 2-in-1, but the other dimensions are quite close. Of course, the XPS 13 has that bigger InfinityEdge display!

I needed to find a bag!

I still have an old Dell bag that my Fujitsu P2120 used to call home. It is only just barely big enough for the Chuwi Hi12. Most of the time, I expect to walk out of the house with only the Chuwi. When I do take the bag, I’d like to have room for a little more than just the power cable.

I ended up buying the AmazonBasics 11.6-inch laptop bag. The Chuwi Hi12 fits perfectly, and it has two additional zippered pockets to store all my extra gear. It also has a shoulder strap—something my old Dell bag was lacking.

As usual, I packed the bag with enough gear that its bulging at the seams. Even so, the total weight of the fully loaded bag is less than six pounds. That’s more than three pounds lighter than my old 18.4” laptop, and I can even fit the new bag inside my old bag—even with the old laptop and all my old gear!

Is the Chuwi’s little Z8300 Atom processor fast enough?

Fast enough for what? My old i7 laptop is almost three times faster and has four times more RAM than my little Chuwi Hi12. In other words, the Chuwi isn’t a screamer, but it does well enough at the tasks I’m willing to tackle on a 12” display.

I was stubborn at first. I tried to use Mozilla Firefox—just like I do on all my other machines. I thought it would be more convenient to have access to all my browser extensions and synchronized bookmarks.

Don’t even bother. Just use Microsoft Edge. It feels infinitely more responsive than Firefox on an underpowered machine like the Chuwi Hi12, and it supports proper tablet-style pinch-to-zoom. Firefox just scales in 10% increments when you pinch the screen, and it does so at a glacial pace!

I’m happy enough with the performance of the Chuwi Hi12 for my use case—web browsing, email, text editing, and some light gaming. Steam streaming works about as well as it does on my Steam Link over Wi-Fi, too!

Where can you buy the Chuwi Hi12?

You can’t get one at your local Best Buy. I bought the first Chuwi Hi12 and keyboard from Gearbest for about $280. They estimated that it would take nearly a month for my tablet to arrive at my door, but it only took about two weeks. That’s still a long time, and I worried about whether or not the tablet would actually make it to my door.

We ordered our second tablet from Amazon. The tablet-and-keyboard combo was $360 with Prime shipping. The pricing at both Amazon and Gearbest seem to fluctuate quite a bit, too. The Chuwi Hi12 is still a great value at $360, and the extra $80 wasn’t a waste. It was nice not having to wait two weeks for the package to arrive, and it was a comfort knowing how quickly and easily Amazon will resolve any shipping issues.

You can also find the Chuwi tablet on eBay—usually somewhere in between the prices at Gearbest and Amazon. I haven’t bought a Chuwi Hi12 from eBay, but it is definitely a good place to look.

Charging your Chuwi Hi12

The Chuwi Hi12 comes with a 3-amp USB charger. I wanted a long charging cable for my bag, but I know that as cables get longer, their charging efficiency drops. I found a 10’ USB cable with nylon braiding for a reasonable price at Amazon. It had good reviews, but I didn’t trust those reviews, and I was curious how the USB cables I have around the house stacked up, so I also bought a USB power meter to test all my cables.

The results of my tests were surprising to me, and I’ll definitely be gathering my data and writing up a blog post. For this post, I think it is enough to say that the Volutz cables are some of the best cables I own. I liked the 10’ Volutz USB cable so much that I ended up ordering their assorted 5-pack as well.

I also picked up a compact USB charger to keep in my laptop bag. It folds up for easy storage, and the RAVPower 24W charger has a pair of 2.4-amp USB ports, so I can quickly charge my phone and tablet at the same time.

What about other Chuwi tablets?

Chuwi manufactures a wide array of tablets with Intel Z8300 processors with 8”, 10”, and 12” displays. Their 8” inch tablet can be had for as little as $80, but it only has 2 GB of RAM.

The Chuwi Hi10 is a very interesting machine, though. The specs are almost identical to my Chuwi Hi12, except it has a 10” 1920x1200 screen and a less-awesome-looking keyboard. I’ve seen the price on the Chuwi Hi10 with the keyboard dock drop as low as $180.

The Chuwi Hi10 is comparable to the 10” Microsoft Surface 3 tablet, but it sells for less than half the price.

In my opinion, the two best features of my Chuwi Hi12 are the keyboard dock and the screen. I’m more than happy to pay for the upgrade over the Chuwi Hi10.

The verdict

I’m extremely pleased with the Chuwi Hi12. I expected to qualify most of my statements about the Chuwi with “for the price,” but for the most part, I didn’t have to. It may not be up to Apple’s standards, but the build quality is better than some laptops I’ve owned—certainly better than most budget laptops.

The Chuwi Hi12 tablet is a low-end Ultrabook for the price of a Chromebook. That’s a bit of an oxymoron, since Ultrabooks are defined as high-end subnotebooks. Even so, I still say it is a good description of what the Chuwi Hi12 is.

If the hardware specs of the Chuwi Hi12 fit your use case, I just can’t recommend it highly enough. I’ve bought three so far—one for me, one for my wife, and one for my father-in-law. They’re all working great, and everyone we show the Chuwi to ends up finding it fascinating.

You can use the Gearbest coupon codes to save yourself a few dollars.

My First Week with the Steam Link and Steam Controller

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UPDATE: I have an extra Steam Link, and I’m giving it away! Follow me on Twitter and retweet this tweet for a chance to win!

I’ve been interested in both the Steam Link and the Steam Controller ever since they were announced. I haven’t been playing many console games lately, so I’ve been doing most of my gaming at my desk with a mouse and keyboard. I’ve been running a weekly Video Game Night at for the last couple of months, and that’s gotten me interested in playing something besides Team Fortress 2 again. Because of that and Valve’s sale on the Steam Link and Controller last week, I finally had to break down and buy them.

Steam Link, Steam Control, and Rascal

And I’m glad that I did! Each device fills a gap in my gaming experience, and I’ve been using one or both of them almost every day so far.

The Steam Controller

My Controller arrived one day earlier than the Link. As soon as it got here, I plugged its dongle into my computer and fired up Super Meat Boy. I expected to have a bad time using the emulated d-pad on the Steam Controller, but I got used to it pretty quickly, and I was breezing through levels at a reasonable pace.

I’d rather play Super Meat Boy with a good d-pad, like the one on an Xbox One controller or any controller from Nintendo—even the subpar d-pad on the Xbox 360 controller isn’t all that bad. The emulated d-pad on the Steam Controller is quite usable, though, and I bet you I’ll like it even more as time goes on.

Steam Controller and Xbox 360 Controller

Then I tried Saints Row: The Third. This was a a good way to try out the Steam Controller’s touchpad aiming with gyro assist. This unique way of aiming is rather intuitive, but continuing my game that was already set to the highest difficulty level was like jumping right into the deep end of the pool. I felt like I was doing a good job aiming, but I wasn’t picking off headshot after headshot in rapid succession like I can with the mouse.

I took my Steam Controller to’s weekly Video Game Night last week, and I let everyone try Saints Row with the Steam Controller. My friend Brian gave it a shot first, and he didn’t find it intuitive at all. He was flailing about, trying his best to shoot at the bad guys, but he just couldn’t do it well. He ended up resorting to fisticuffs. We had the fresh game of Saints Row set to the easiest difficulty, so this worked out alright for him.

Three or four other people tried, and most of them were clicking off fairly quick headshots within a few minutes. Brian ordered his own controller, and it is on its way as I’m writing this. I bet he’ll manage to get the hang of it soon!

The Steam Link

The Steam Link is a small box—not much bigger than the Amazon FireTV—that streams games from your computer to your television, and it does a fantastic job. It operates well enough over Wi-Fi. It is responsive enough to play Super Meat Boy, and I played at least an hour of Borderlands 2 over Wi-Fi. Unfortunately, my Wi-Fi signal isn’t the best here, and the Steam Link eventually had connectivity issues—I blame the neighbors! I’ve plugged it into my network since then, and both Valve and I recommend you do the same.

I wanted to play a game on the Link that I was already familiar with in order to hone my first-person-shooter skills. I chose Borderlands 2. I’ve played through the game more times than I can count, and the game is ridiculously easy when you start a new character.

Things started out pretty rough. I died in lots of embarrassing ways, but things improved rather quickly. I managed to get past Boom Bewm and Captain Flint without much fuss. Shortly after that, some friends of mine started popping in and out of the game to help me out.

At first, I thought, “Oh great! These guys are going to be doing all the work for me with their fancy, fast-aiming mice!” Things went better than I had anticipated. I wasn’t dying much more often than everyone else, and I was nearly doing my fair share of damage to the enemies. The Steam Controller makes me feel like the most inexperienced guy in the group, but I could see that skill gap closing every day.

On the first day, I could only hit slow-moving targets at a distance. I have the most trouble when they charge at me, and get right up in my face. On the first day, those enemies were nearly impossible to hit, and I had to backpedal to get them into my sights. Today, I can at least aim at them, but not as quickly or accurately as I’d like.

Even a few days in, I still couldn’t hit flying enemies like Rakk or Buzzards. After a week, I can manage to get a few hits and kills in. A lot of enemies are easier to hit when I play solo, since they’re all coming right at me, and this is especially true with these flying enemies. They’re much harder for me to hit when playing with friends, but I do manage now.

I’m getting better at using sniper rifles—I can often hit a Hyperion robot in the shoulder before one of my friends takes the kill on me.

The best part is that all the practice with Borderlands 2 transferred well to Saints Row. I look significantly less ridiculous trying to shoot things in Saints Row, but I still may need to start a new game on “normal” difficulty.

Do you know what’s really awesome about the Steam Link? My desktop computer is significantly faster than an Xbox One or PlayStation 4, and I have hundreds of games in my Steam library. Tons of those games are better played from the couch or your favorite recliner using a controller, and the $50 Steam Link is a fantastic way to do that.

You may have noticed that even though this section has a heading of “Steam Link,” I ended up talking about the Controller even more. There really isn’t that much interesting to say about the Link. It has one job to do, and it does it extremely well.

Should you buy both?

The Link and Controller make a good pair, but each one can provide quite a bit of value on its own. The Link functions just fine with other controllers—I plugged in my Xbox 360 Wireless dongle, and I had no trouble powering up the Link and playing Super Meat Boy. The d-pad on the Xbox 360 controller may not be the best, but it is more appropriate for a twitchy platformer like Super Meat Boy.

Steam Controller Packaging

Likewise, the Steam Controller will work just fine on your PC or laptop. I know some people that plug their laptop into their TV to play games—heck, we used to plug my laptop into the TV every week for Video Game Night at!

Personally, I’m glad I bought both. I once played through Saints Row: The Third on the PlayStation 3, and I recently played through half of the game on my computer with the keyboard and mouse. Driving on the PlayStation 3 was fantastic—driving with the keyboard is just awful. On the other hand, aiming with the mouse is a huge upgrade over the PS3.

The Steam Controller tries to provide the best of both worlds. Driving with the Steam Controller’s analog stick feels great, and aiming is so much more comfortable than it was on the PS3. I may not be able to aim as quickly and accurately as I can with the mouse, but I’m doing better than I can with an analog stick, and I’m getting better every day.

Do you own a Steam Controller or Link? What do you think of them?

I Almost Bought an Acer Predator X34

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I’m getting impatient. I want to upgrade to a newer, bigger, 4k monitor, but there aren’t any available that interest me. I wouldn’t mind having a slightly higher pixel density than my 27” WQHD monitors, and more pixels and screen real estate would be an excellent productivity booster, but I’m much too attached to 100+ Hz gaming to give up my QNIX QX2710 monitors just yet, because there are no 4K UHD monitors that can accept an input greater than 60 Hz.

This is a lie.  My current monitors aren't debezeled.  I don't have a more recent picture!

There is a stepping-stone between my overclocked 2560x1440 monitors and my hopeful future with 100+ Hz 3840x2160 monitors—the Acer Predator X34. The Predator X34 is an ultrawide 34” 3440x1440, and it can be overclocked to 100 Hz. It may not be the 4k upgrade that I want, but it is fully 1/3 wider than my existing monitors, and anything that hits 96 Hz or more will satisfy my need for a higher refresh rate.

At $1,200, the Acer Predator X34 is an expensive monitor. There are plenty of larger 4k monitors for half the price. Is a smaller, curved, 100 Hz monitor with 60% fewer pixels worth that kind of price premium?

I came to my answer pretty quickly. It just wasn’t a worthwhile upgrade for me.

Acer Predator X34 vs. QNIX QX2710

I have a pair of QNIX QX2710 monitors on my desk. Mine are overclocked to 102 Hz, and they cost about $250 each these days. You can buy four of these for less than the price of a single Acer Predator X34, and you’ll have more than enough left over to buy some nice monitor arms.

Even so, the Predator X34 was still very tempting. I find all the ultrawide 1440p monitors interesting. I’m very pleased with the height of my QNIX monitors—if they were any taller, I’d be craning my neck more than I’d like. The 34” ultrawide monitors are about 30% wider than my QNIX monitors, and I currently find that’s very close to what fits in my field of view.

My QNIX QX2710 Monitors and Articulated Stand

In theory, I could probably get by with a single monitor if it’s an ultrawide. In practice, though, I wouldn’t give up my existing monitors. I’d end up sandwiching that 34” ultrawide Acer Predator in between my existing QNIX QX2710 monitors. That’s just too much screen real estate, even for my large desk. My monitors are already over 4’ wide. If I added a 34” ultrawide, they’d be approaching the 7’ mark! I’d be constantly rotating myself, and I don’t want to have to do that.

The Acer Predator X34 sounds a little scary

Every time the Predator X34 goes on sale, I see all sorts of horror stories on Reddit about people having to send them back two or three times before finally receiving an acceptable monitor. It seems that most of the returns are related to backlight bleed.

I can live with some backlight bleed, and I expect it from a budget-friendly IPS monitor like the QNIX QX2710. However, I hope to acquire a more perfect specimen when spending $1,200.

I’m holding out for 4k

It has been almost a year since I last contemplated a monitor upgrade. At the time, my QNIX QX2710 monitors were still the right choice for me. If you’re a gamer, and you appreciate a monitor with a high refresh rate, the QX2710 is an amazing value. The Acer Predator X34 will be a good stepping-stone on the path to high-refresh-rate UHD monitors, but not with its current $1,200 price tag.

You can almost buy three Korean 2560x1440 monitors for half the price of the Predator. That would leave you with enough cash in your wallet for an Nvidia GTX 1080, and that’s the sort of video card you’ll need in the future if you want to drive a 3840x2160 monitor at anything close to 120 Hz!

Nearly twelve months after writing a post titled “Would I Still Buy a QNIX QX2710 in 2015,” I find myself asking essentially the same question. Would I still buy a QNIX QX2710, or any of the many other equivalent Korean monitors, in 2016? The answer is still an enthusiastic “yes,”“ and I bought two more for my wife’s desk last month, but I bet there are better alternatives on the horizon for gamers like me—gamers that want large, high-resolution monitors that are faster than 60 Hz!

Prime Lenses: Canon 50mm f1.8 vs Yongnuo 35mm f2.0

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Back in January, I purchased a used Canon XSi DSLR. It was a huge step up over the camera on my phone, and thanks to my friend Andy, it didn’t take long to start learning about things like f-stop, shutter speed, and ISO. I am far from an expert, but I feel like I’m quickly working my way past novice status.

Canon 50mm f/1.8 and Yongnuo 35mm f/2.0

I had a lot of fun with the Canon 18-55mm kit lens that came with my camera, but my research told me it wasn’t a great lens. I read about the “Nifty Fifty”—the f/1.8 50mm Canon prime lens. I asked Andy about this 50mm “fixed-zoom” lens, and he explained to me that I shouldn’t say “fixed-zoom” ever again. He did confirm that the 50mm prime was a great idea, and since it was so inexpensive, I ordered one immediately.

In fact, I was so pleased with my Canon 50mm f/1.8, that on the day my lens arrived, I immediately ordered one for my friend Brian.

Why choose a prime lens?

Unlike zoom lenses, Prime lenses have a fixed focal length. This makes prime lenses much simpler, smaller, and cheaper. Zoom lenses with a fast f-stop of f/2.8 start at around $500, while the faster Yongnuo 50mm f/1.8 only costs around $60.

The Canon 18-55mm kit lens is almost twice as long as either of my prime lenses. They may not be as small as Canon’s pancake lens, but my camera feels quite a bit less bulky when I’m using a prime.

While the size, fast f-stop, and price of the prime lenses are all great, not having zoom is sometimes problematic. I take a lot of great shots with my 35mm and 50mm lenses, but I can’t always stand in an appropriate location. A fast zoom lens may cost five or ten times as much as either of my primes, but there are definitely circumstances where I would have appreciated that zoom.

That said, a prime lens is an extremely inexpensive way to take some amazing shots.

Canon EF 50mm f/1.8

The “Nifty Fifty” is a fantastic lens. The f/1.8 is very handy. A lower f-number means a wider aperture, and a wider aperture means more light and more bokeh. My 18-55mm kit lens has an f-stop range from f/3.5 to f/5.6. Unfortunately, the kit lens can only reach f/3.5 when zoomed out to its widest angle. I can rarely zoom out that far, so most of the time I was operating at f/4.0 or f/5.6.

Canon 50mm f/1.8 Some friends of mine at Whiskey Tasting event at

Being able to shoot at f/1.8 was like using a brand-new camera. I can shoot without the flash indoors with the “Nifty Fifty,” whereas my kit lens would never work without a flash. I also really enjoy the bokeh at f/1.8—that’s the big out-of-focus area in front of and behind the focus of the shot. I like not having to worry about the backgrounds of my photos being perfectly neat and tidy!

Canon 50mm f/1.8 vs. Canon 18-55mm

Knowing what I know now, I wouldn’t buy the Canon 50mm lens. Yongnuo makes a 50mm f/1.8 prime lens that sells for less than half the price of the Canon. I haven’t had the opportunity to try the Yongnuo 50mm, but I’m extremely pleased with my Yongnuo 35mm prime lens. I expect Yongnuo 50mm f/1.8 to be similarly well made.

Is a full-frame 50mm lens the right choice for a crop-sensor DSLR?

I have a lot of fun with my 50mm prime lens. So much fun, that I almost completely stopped using the kit lens. It isn’t perfect, though. Since I can’t zoom with the lens, I have to zoom with my feet. On my low-end, crop-sensor DSLR, the 50mm lens has an apparent length of 80mm—that means I have to stand even farther away than with the 18-55mm kit lens when it is at full zoom. Sometimes that isn’t even possible!

Marvin with 50mm f/1.8 Marvin with 35mm f/2.0

I researched other prime lenses. I was tempted by the Canon EF-S 24mm f/2.8 pancake lens. At $150, I thought it was on the expensive side—especially considering that f/2.8 is one full stop slower than the “Nifty Fifty.” I also want to avoid buying any more EF-S lenses, because they won’t work on a full-frame DSLR, and I’d like to keep my upgrade options open.

Yongnuo EF 35mm f/2.0

When I saw the Yongnuo 35mm f/2.0, I purchased it almost instantly. The f-stop is almost as good as my 50mm f/1.8, and it is under $100—less than one quarter the price of the Canon 35mm f/2! How could I go wrong with this lens?

Rascal and Butters Mario at The National Video Game Museum in Frisco, TX Brew Night at

The Yongnuo 35mm is by far my favorite lens in my bag—it has barely been off my camera since it arrived, and I’ve taken over 1,000 shots with it already. I take photos with the Yongnuo 35mm that are every bit as good as the shots I got with the Canon 50mm, but it is usually much easier to frame my shots with the 35mm.

When I used to use “Nifty Fifty,” I found myself trying to get farther away, and I was backing into things all the time. Sometimes I’d run into something like a table, and I’d be able to walk around it to get my shot. Other times, though, I’d back into a wall—there’s no shooting through a wall.

What’s next?

I’m extremely interested in acquiring a fast zoom lens with a big aperture. I’m considering either the Tamron 28-75mm f/2.8 or the Tamron 24-70mm f/2.8. One of these lenses is quite inexpensive used, but it lacks image stabilization. Both lenses have an f-stop of f/2.8 when wide open or zoomed in, which seems intriguing. It may have been a better value to buy a used Tamron 28-75mm zoom lens instead of a pair of brand-new prime lenses.

What do you think? Do you enjoy your prime lenses? Will I be as happy with an f/2.8 zoom as I am with my f/1.8 and f/2.0 prime lenses?

Infiniband: An Inexpensive Performance Boost For Your Home Network

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Gigabit Ethernet ought to be fast enough for anybody, right? It usually is, at least for me. Heck, even Wi-Fi is fast enough for most of my local streaming and Internet needs. I am impatient every now and again, and when I’m impatient, I think about what I might do to upgrade my home network.

Copper CX4 Cable for Infiniband

My friend Brian decided to add 10 Gigabit Ethernet to his home network. I would enjoy having a faster link between my desktop computer and virtual machine server, and I didn’t want Brian to leave me behind in the dark ages, so I decided to give Infiniband a try.

Why Infiniband?

As it just so happens, used Infiniband hardware is fast and inexpensive. It isn’t just inexpensive—it’s downright cheap! I bought a pair of 2-port 20-gigabit Infiniband cards and a pair of cables on eBay for less than $70. That $20 per card and $15 per cable.

If that’s not fast enough for you, 2-port 40-gigabit cards don’t cost a lot more. I figured I’d save a few bucks on this experiment, since I don’t have fast enough disks to outpace a single 20-gigabit port. In fact, the RAM in my little server probably can’t keep up with a pair of 20-gigabit ports!

I decided to be optimistic, though. I bought two cables just in case 20 gigabits wasn’t enough.

I bought Infiniband cards with CX4 ports. The cards aren’t always labeled well on eBay, though. Most of the CX4 Mellanox-brand cards will have XTC in their model number. My Mellanox cards were rebranded as HP, so they don’t have those helpful part numbers. Luckily for us, pictures of the cards make it terribly obvious.

You can buy used Infiniband gear at Amazon or eBay. I usually prefer the convenience of Amazon, but the prices are quite a bit better at eBay.

How is Infiniband different than 10 Gigabit Ethernet?

10 Gigabit Ethernet is another incremental upgrade to the Ethernet protocol, and it works with TCP/IP in exactly the manner you’d expect. You can run IP over Infiniband, but that isn’t what it is designed for—you lose the advantages of Infiniband’s Remote Direct Memory Access (RDMA). I knew before ordering my Infiniband cards that this might cost me some performance, but I didn’t know how much.

I can run iSCSI over RDMA, and these Infiniband cards should be fast enough that I wouldn’t be able to tell if an SSD were plugged into the local machine or the server on the other side of the Infiniband cable.

Even though I don’t currently have a need for iSCSI, I did initially plan to test its performance. However, you need to install all sorts of third-party OFED packages to make use of iSCSI. I don’t need any of those packages to use IP over Infiniband (IPoIB), so I didn’t think it was worthwhile to pollute my desktop and homelab server with extra cruft.

Performance is much better than Gigabit Ethernet, but I have a bottleneck somewhere

IP over Infiniband (IPoIB) was easy to set up. The Infiniband network interfaces default to datagram mode, which was extremely slow for me. Putting the interfaces in connected greatly improved my speeds. I am able to push around 5.8 or 6.5 gigabits per second between my little server and my desktop computer, depending on which direction the traffic is flowing.

I had no idea how much network performance I’d be giving up to the extra memory-copying requirements of IPoIB. 6.5 gigabits per second is well short of the theoretical maximum speed of 16 gigabits per Infiniband port, but it is already a HUGE improvement over my Gigabit Ethernet ports.

IP Over Infiniband Bandwidth Test

At first, I had assumed my speed limitation was caused by the low-power CPU in my KVM server—I certainly didn’t choose it for its performance. During all my early testing, iperf’s CPU utilization was always precisely 50%. While writing this blog, however, I’m seeing 55% utilization when testing in one direction and 74% in the other.

I’ve also tested RDMA and rsocket performance, which should both be much faster. The RDMA benchmark tools were no faster than my IPoIB iperf tests, and my tests using iperf yielded identical performance as well. Those LD_PRELOAD tests with were definitely working correctly, because there was no traffic over the IPoIB link during the test.

[    1.709385] mlx4_core: Mellanox ConnectX core driver v2.2-1 (Feb, 2014)
[    1.709449] mlx4_core: Initializing 0000:02:00.0
[    4.001247] mlx4_core 0000:02:00.0: PCIe BW is different than device's capability
[    4.001301] mlx4_core 0000:02:00.0: PCIe link speed is 2.5GT/s, device supports 2.5GT/s
[    4.001356] mlx4_core 0000:02:00.0: PCIe link width is x4, device supports x8

These results led me to dig deeper. Before ordering these Infiniband cards, I knew I remembered seeing an empty PCIe 16x slot in both my desktop and my KVM server. As it turns out, both of those slots are only 4x PCIe slots. Uh oh!

02:00.0 InfiniBand: Mellanox Technologies MT25418 [ConnectX VPI PCIe 2.0 2.5GT/s - IB DDR / 10GigE] (rev a0)
        Subsystem: Mellanox Technologies MT25418 [ConnectX VPI PCIe 2.0 2.5GT/s - IB DDR / 10GigE]

According to lspci, my Mellanox MT25418 cards appear to be PCIe 2.x devices, so they should be capable of operating at 5.0GT/s—that’s 16 gigabits per second. Unfortunately, they’re running at half that speed. This easily explains my 6.5-gigabit limit, but I had to dig deeper to figure out why these cards identify as PCIe 2.x while operating at PCIe 1.x speeds.

The Mellanox site says that the MT25418 cards are PCIe 1.x and the MT26418 cards are PCIe 2.x. As far as I can tell, the Mellanox cards with model numbers that contain an 18 or 28 are PCIe 1.x,while model numbers containing 19 or 29 are PCIe 2.x.

Unfortunately, the faster cards cost four times as much. If you don’t have 8x or 16x PCIe slots available, and you need to double your performance, this might be a worthwhile investment. For my purposes, though, I am extremely pleased to have a 6.5-gigabit interconnect that only cost $55. That’s roughly 800 megabytes per second—faster than most solid-state drives.

You can’t bond IPoIB connections

My extra Infiniband cable was completely useless for me. It took me a while to learn that my cards just aren’t capable of maxing out even a single DDR Infiniband port in my machines. Of course, before testing anything at all, the first thing I tried to do after a successful ping was attempt to bond my two Infiniband ports.

ifconfig ib1

You can’t do it. IPoIB runs at layer 2, and the Linux kernel can only bond layer-1 devices. You can use the channel bonding interface to set up automatic failover, but you can’t use channel bonding to increase your IPoIB bandwidth.

This led to a second problem.

You can’t attach KVM virtual machines to IPoIB interfaces

KVM can only bridge directly to layer-1 network devices. This seemed like an easy problem for an old-school network engineer like myself. I figured I’d just need to create a new bridge device on the KVM server with a new subnet. Then I’d just need to route from the IPoIB subnet to the new virtual subnet. Easy peasy, right?

It should have been easy, but I spent days trying to make it work. I knew I had to set those giant Infiniband MTUs of 65520 on all these interfaces, but I just couldn’t get decent speeds when routing. At first, I was getting 5 or 6 gigabits per second in one direction, but I wasn’t even hitting DSL speeds in the opposite direction.

It was easy enough to fix, and I’m more than a little embarrassed to tell you what the problem was. I missed an important interface. I just couldn’t set the MTU on my KVM bridge to 65520. It failed. As it turns out, you can’t set the MTU of a bridge device to 65520 if the bridge isn’t already bridged to another interface.

IP Over Infiniband To Virtual Machine Bandwidth Test

When my virtual machine on that bridge starts up, it creates a vnet0 device and immediately attaches it to the bridge. Once that device is created, you can set its MTU to 65520, and then you’ll be allowed to set the MTU of the bridge to 65520. Then everything works as expected.

I am losing some performance here. I can “only” manage 5.6 or 4.6 gigabits per second between a virtual machine and my desktop computer. That’s still four or five times faster than my Gigabit Ethernet network, so I can’t complain.

How do I configure these IPoIB and KVM interfaces?

Documenting my new network and KVM configuration would probably double the size of this blog post, so I’m going to do a separate write-up on that soon. I will summarize things here, though!

You need an Infiniband subnet manager. I’m under the impression that one of these may already be running on your Infiniband switch, assuming you have one. I’m only connecting these two machines, so I don’t have a switch. I’m running opensm on my KVM server. I don’t believe I had to do anything to configure opensm after installing it.

Setting up the link between the two physical hosts was extremely easy, and it only required a few extra lines in my /etc/network/interfaces file to put the IPoIB links into connected mode. Other than that, they look just like any other network device.

auto ib1
iface ib1 inet static
  pre-up modprobe ib_ipoib
  pre-up echo connected > /sys/class/net/ib1/mode
  mtu 65520

I am not routing any traffic between my Infiniband subnet and my old Ethernet subnet. It isn’t necessary, since both machines on my Infiniband network are also on the Ethernet network.

The verdict

I’m quite pleased with my Infiniband experiment. It may have a few quirks that can be avoided if you use 10 Gigabit Ethernet instead, but Infiniband costs quite a bit less, especially if you have enough machines that you need to use a switch—there are plenty of 8-port Infiniband switches on eBay for under $100!

Had I known ahead of time that the Infiniband cards I chose only supported PCIe 1.x, I would have spent more to upgrade to faster cards. If I had done that, though, this would probably be a much less interesting blog post. I can’t really complain about the performance I’m getting, either. All the disks on my KVM host machine are encrypted, and its CPU can only process AES at about seven gigabits per second. These cards are still just about fast enough to push my hardware to its limits.

I convinced my friend Brian to build a heavy-duty, dual-processor homelab server using a pair of 8-core, 16-thread Xeon processors. I don’t really have a need for a beast like that in my home office, but I haven’t built anything like that just for the fun of it in a long time. I may end up building a similar machine later this year to add to my Infiniband network!

Emacs: Automatically Adjust Font Size When Frame Width Changes

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I get annoyed when I resize Emacs, and the window becomes narrower than 80 columns. I’ve had a solution to this problem floating around my head for years, but I just haven’t run into this situation often enough to implement an automated solution. On those rare occasions, it’s just been easy enough to hit a key to change the font size.

Narrow Emacs frames have become more annoying for me recently, so I figured it was about time to create an elisp function that would set the font size based on the width of my Emacs frame. In my case, this turned out to be quite simple. I’m not a fan of tiling window managers—I’ve tried a few, but they always felt uncomfortable.

Emacs at Two Fonts Sizes

I attacked this problem from the other direction. I use the Sawfish window manager, and I have some handy customizations that divide my monitors into columns. These columns aren’t of equal width. My 1080p laptop has a narrow column on the left and a wide column on the right. The 1440p monitors on my desktop have a wide column in the center with narrow column on either side.

These columns are roughly the same width on my desktop and laptop—the desktop just gets an extra column on each monitor. The narrow columns automatically tile vertically, and they’re just wide enough to fit an 80-column terminal window with a comfortably font size.

I have convenient key bindings to push the focused window into any of these columns on either monitor, but I also have some automation that moves new windows into appropriate places—Firefox in the wide column, Thunderbird in the narrow column on the left, and Pidgin chat windows get stacked in the narrow column on the right.

On my desktop, Emacs goes in the wide column in the center of my second monitor. It is usually flanked by several terminal windows. Emacs and my terminal windows both use the Solarized color theme and Inconsolata for their font, but I prefer Emacs to have a larger font size. This is fine, until I decide to push Emacs into one of the narrow columns. Sometimes I actually have two Emacs frames open at the same time. Other times I’m reviewing proofreading notes that I’ve received from my editor—LibreOffice often requires the wider column for the editing notes to be large enough to read.

(defun pjr-font-scale-on-frame-width ()
  (if (< (frame-width) 76)
      (text-scale-set -1.1)
    (text-scale-set 0))

(add-hook 'window-configuration-change-hook 'pjr-font-scale-on-frame-width)

At my usual font size, the Emacs frame isn’t much more than 60 characters wide in my narrow columns. As I said, this is easy enough to fix manually, but I’m sick of doing things manually. If my office lights can shut off automatically when Steam launches a game, then surely Emacs can change my font size automatically as well!

My use case is quite simple, since I only need to use two different font sizes. I hooked a function into Emacs that runs any time the window configuration is changed. If the frame is less than 76 characters wide, it scales down the font. Under any other circumstances, it sets the font to the default size.

Camera Strap Upgrade For My DSLR

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Late last year, I bought a used Canon DSLR. It was an excellent purchase, and I’ve had tons of fun using it to learn more about photography. The DSLR is a lot bigger and bulkier than my phone, but the photos I can shoot with the DSLR just look so much better than anything I’ve ever shot with a camera phone.

There is one thing that has annoyed me about my DSLR since day one—the camera strap. The strap is invaluable when I take my camera out with me—but it is way too bulky to fit in my pocket! The neck strap that comes with every DSLR quickly becomes uncomfortable, and when I’m shooting at home or on a tripod the strap just gets in the way!

My research quickly told me that a shoulder strap is the way to go, and there’s a huge selection to choose from!

I quickly figured out what to avoid

My first instinct was to look at the cheapest shoulder straps I could find. Camera straps are just fabric belts with hooks on the end. How bad could a cheap one be?

As it turns out, a cheap strap can be an extremely bad idea! I read several horror stories about the cheaply made hooks on some straps breaking and resulting in hundreds or thousands of dollars’ worth of camera gear crashing to the ground!

The Altura Quick-Release Shoulder Strap

I looked at quite a few camera straps, but my search kept bringing me back to the Altura Quick-Release Strap. The reviews are good, it has a lot of useful features, and it is only about $20. These are the features that interested me:

  • Sturdy quick-release clip
  • Steel bracket that attached to the tripod mount
  • Pocket in the strap for SD cards and batteries
  • Optional two-point connection to camera

The Altura shoulder strap comes with a steel connector plate that attaches to the bottom of your camera using a big, sturdy tripod screw. The plate has a hole on one end that fits the quick-release clip, and a slot at the other end that can fit a regular camera strap.

Altura Quick-Release Strap

The strap comes with both the quick-release clip and a regular camera strap connector. If you’re very worried about your expensive and heavy camera and lens coming loose, you can attach the normal-style camera strap to the body, and attach the quick-release to the tripod plate. It would be amazingly difficult to accidentally separate the camera from the strap in this configuration!

I’m extremely pleased with the quality of the quick-release clip. It is made from sturdy metal, and the hooks on either side of the clip overlap by almost half an inch when closed. I don’t think my camera is ever going to come loose, and it would be impossible for me to accidentally clip on the camera incorrectly.

How I use the quick-release shoulder strap

I use my camera around the house most of the time. Around here, I always have somewhere to put the camera down, so the neck strap is just a nuisance. My new shoulder strap spends most of its time in my camera bag.

The heavy-duty bracket that came with the strap has found a permanent home on the bottom of my Canon DSLR. It doesn’t get in the way very often, and with it in place, it only takes me a few seconds to clip the strap back on and head out the door with my camera. This is extremely convenient!

The large bolt that attaches the bracket to the camera has a threaded hole in the bottom, and it can be connected directly to your tripod. When I read the product description, I thought this sounded scary. After using this bolt, though, I am very confident that it isn’t going to snap if I attach it to my tripod.

Alutra Quick-Release Strap

I don’t think I’d be likely to use this feature. The bracket on my tripod has a lot of surface area that comes in contact with the camera. At the very least, I’d worry that I’m losing some stability. Even worse, I’d worry about the plastic bracket on the tripod giving way.

It only takes a few seconds to disconnect the bracket, so I don’t think this is a big deal.

My only complaint

All the videos I’ve watched show people reaching across their bodies to lift up the camera with their left hand. I prefer to reach for the camera with my right hand. That means I have to attach the bracket facing in the opposite direction.

The battery door is blocked when you attach the bracket this way. It would be nice if this wasn’t the case, but it really doesn’t cause much trouble—it only takes a few extra seconds to loosen the bracket. It would be simple enough for the manufacturer to correct this problem—they just need to add a second slot for the tripod-mounting bolt.


I took my new shoulder strap to the Texas Pinball Festival last weekend. That was the first time I carried the camera with the strap for several hours, and it did an excellent job! I could almost completely forget that I was carrying my camera while playing pinball, but it was still sitting right there at my side ready to take photographs.

Brian at the Texas Pinball Festival

I don’t think I could play pinball with my camera on a neck strap!

Using dm-cache / lvmcache On My Homelab Virtual Machine Host To Improve Disk Performance

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Last year, I built a reasonably fast and energy-efficient server to host KVM virtual machines in my office. I included a pair of 240 GB Samsung EVO 850 solid-state drives. That gives me a fast RAID 1 for the operating system, and I was hoping to use the rest of the available space for dm-cache.

dm-cache (a.k.a. lvmcache) is a block device caching layer that was merged into the mainline Linux kernel back in April of 2013. It is a “hotspot” cache that lets you use fast SSDs to cache reads and writes to your slower, old-school spinning media.

Samsung EVO 850 SSD

When I set up my little server, I installed Ubuntu 14.04 LTS. This seemed like a good idea, since I didn’t want to have to touch the host operating system very often. Unfortunately, the dm-cache tools that ship with the 2014 version of Ubuntu aren’t very advanced—you had to do your own sector-level math when setting up your cache.

I tried to get dm-cache going anyway, but I didn’t do a very good job. It seemed to be caching, but my spinning disks were being written to at a constant 1 MB/s for days, and my benchmarks didn’t show any improvement. This seemed like a failure, so I turned off dm-cache.

The Ubuntu 16.04 release is now only a few months away, so I decided to upgrade early to properly test out dm-cache.

Should I be talking about dm-cache or lvmcache?

I haven’t figured this out yet. When I started researching this last year, I don’t remember seeing a single mention of lvmcache. This year, you almost exclusively use lvm commands to set up and control your dm-cache.

I don’t think you can go wrong using either name. It is dm-cache in the kernel, and lvmcache in user space.

What was I hoping to get out of dm-cache?

I had a feeling dm-cache wouldn’t meet all of my expectations, but I thought it was worth giving it a shot. Here are some of the benefits I was hoping to see when using dm-cache.

  • Faster sequential reads and writes
  • Faster random reads
  • Much faster random writes
  • Power savings from sleeping disks

Performance improvements

dm-cache is a hotspot cache—much like ZFS’s l2arc and zil. These hotspot cache technologies may not improve your synthetic benchmark numbers, as my friend Brian recently discovered. At first, I didn’t find any performance improvements either, but this was my own fault.

When I upgraded from Ubuntu 14.04 to 16.04, I didn’t notice that I was still running the old 3.19 kernel. There’s been a lot of dm-cache progress since then, and I wasn’t able to get the smq cache mode to work with the older kernel. Once I upgraded the kernel and switched to smq, things improved dramatically.

Version  1.97          ------Sequential Output-------- --Sequential Input-- --Random-
Concurrency   1        -Per Chr- --Block--- -Rewrite-- -Per Chr- --Block--- --Seeks--
Machine           Size K/sec %CP  K/sec %CP  K/sec %CP K/sec %CP  K/sec %CP  /sec %CP
ssd mirror      31776M   317  99 298671  60 184190  36  1924  98 588349  60 +++++ +++
platter mirror  31776M   320  99 143929  28 104534  17  1981  95 398087  30 561.6  29 
mq              31776M   279  99 117243  29  94845  19  1496  91 387993  41 548.3  33
smq             31896M   365  99 255449  60 177057  33  1721  93 882116  81 +++++ +++

As you can see from the benchmarks, smq has been a really big win for me. The write speeds are 75% faster than the uncached disks. In fact, the cached writes are almost as fast as the solid-state drives. The read performance is even more impressive—the cached mirror is 50% faster than the solid-state drives alone!

LVM [2.02.133(2)] cache report of found device /dev/raid10_crypt_vg/kvm
- Cache Usage: 41.1% - Metadata Usage: 1.6%
- Read Hit Rate: 85.5% - Write Hit Rate: 94.7%
- Demotions/Promotions/Dirty: 0/971904/6
- Feature arguments in use: writeback
- Core arguments in use : migration_threshold 2048 smq 0
  - Cache Policy: stochastic multiqueue (smq)
- Cache Metadata Mode: rw
- MetaData Operation Health: ok

My cache is over 200 GB. I haven’t even managed to fill half of that, and I’m certain it would work adequately at a fraction of that size. My virtual machines occupy about 2 TB, but the vast majority of that data is taken up by backups and media on my NAS virtual machine. The data that gets accessed on a regular basis easily fits in the cache.

What about power savings?

Most people don’t care about spinning down the hard drives in their servers. My little homelab virtual machine server is very idle most of the time. Spinning down a couple of 7200 RPM hard disks will only save me six or seven watts, but I think it’d be a nice bonus if I could make that happen.

I’ve tried cheating as much as I can, but I just can’t get dm-cache to stop writing to the cached media. I see hours go by throughout the day with no reads on the magnetic media, but with the default smq settings, there is a slow but constant stream of writes to the cached disks. Most of those writes seem to be caused by OpenHAB’s log file.

dstat with dm-cache

I’ve tried cheating by setting the smq’s migration_threshold to zero—low values also seem to work. This often silences the writes to the cached disks, so at least I’m on the right track. Sometimes, the cached disks still see several small writes each minute.

Even when I manage to get dm-cache to keep the cached disks in a very idle state, something is still preventing my disks from going to sleep—even when they haven’t been accessed in over an hour! Google tells me the usual culprits are smartctl, smartd, or hddtemp. I’ve ruled all of these out. I can manually put the disks into standby with hdparm -y, and they will stay asleep for hours.

It would have been nice to get the drives to spin down. They don’t use much power—probably less that 1 kWh every six months—but they are the noisiest thing in my office. Fortunately for me, they don’t need to be in standby to be quiet.

Why not skip the ancient spinning disks?

Solid-state drives are nice, but they’re still small and expensive. At a minimum, I would need a pair of 2 TB ssds in my homelab server. Those 2 TB solid-state drives cost over $600 each. One of those drives costs almost as much as my entire server, and my server has twice as much storage.

The majority of the data my virtual machine server touches regularly fits very comfortably in my 200 GB dm-cache—it has a read cache hit rate of 84.9%. That means my server almost always has the responsiveness and throughput of solid-state drives, while still retaining the benefits of the large, slow, cheap mechanical disks.

I used to have an ssd and a mechanical drive in my desktop, but I had to decide which data to store on each drive. The best part about dm-cache is that I don’t have to worry about that, because dm-cache manages that for me!

Was dm-cache worth the effort?

For a virtual machine host, it was definitely worth the effort. My KVM host is performing much better since enabling dm-cache—almost as well as if I’d only used solid-state disks for my purposes! This is a great value to me, and I can easily and inexpensively add more rotating disks in the future to expand my storage capacity.

I could have saved $50 to $100 if I used smaller solid-state drives, but I’m pleased with my decision to use the 250 GB Samsung EVO 850 SSDs. They have a larger RAM cache than the 120 GB model, but they are still rated for a write load of 41 GB per day—the 500 GB Samsung EVO is rated for 82 GB per day. I won’t be needing the extra endurance of the 500 GB model, and the 120 GB model is just too small for me to make use of anywhere else in the future.