Living La Vida Linux at Work

Android system-level development can be done on either Linux or OSX. For the past few years I’ve been using OSX, but recently I’ve switched over to using Linux.

Why? Mostly for the higher performance. The full Android system build takes about 30% less time under Ubuntu 8.04 LTS than it does on OSX 10.5 on the same hardware. Not to mention that it’s much cheaper to buy a generic PC workstation than the equivalent Mac Pro.

I have had some early troubles:

It took me a while to get used to typing the “Ctrl” key instead of the “Command” key, and the ugly Linux fonts bothered me for a few days.

But since I’m mostly using the exact same programs on Linux as I was on OSX (FireFox, Eclipse, Android), after a few days everything clicked, and I think that I’m just as productive as I was before. And the faster builds and file system stuff (like grep) are wonderful.

It helped a lot to install the Blubuntu theme and some nice wallpaper to get away from the awful Ubuntu brown/orange color scheme.

Oh, and I’m using Chromium for Linux, which works pretty well, except that it doesn’t support Flash. I still fire up Firefox occasionally to watch Flash videos.

See, this is why we can't have nice things (Ubuntu 9.04 Intel Drivers)

A few years ago I tried Ubuntu and predicted it would become a serious challenger to Windows, in about 18 months.

Well, it’s about 18 months later, was I right?

Not exactly. Ubuntu seems to have stood still, if not actually gone backwards. In particular, the newer releases have much worse sound and video performance on my hardware (Intel CPU/GPU Mac Minis) than earlier releases.

The sound driver issue is because Linux, in its typical decentralized fashion, is trying to figure out how to provide a standard audio subsystem, and has two or three competing standards that are duking it out. Since they all suck it seems odd that people defend them so much. Just pick one already.

The video driver issue is because Intel decided to take several years to rewrite their Linux video driver stack, and Ubuntu decided to ship the new broken drivers rather than continue to use the old unbroken drivers. Very very lame on both Intel and especially Ubuntu’s part.

And Phoronix’s performance tests show that the performance of Ubuntu has gone downhill slightly over the last few releases. (With no offsetting user-visible feature improvements.) So we see the problem’s larger than just sound and video drivers.

It’s almost as if the Linux community doesn’t want to be successful.

Microsoft must be laughing all the way to the bank on this one.

The diNovo Edge is a nice keyboard for HTPC

I just bought a Logitech diNovo Edge Mac Edition keyboard for my Mac Mini HTPC. I bought the diNovo instead of the Apple Bluetooth keyboard because:

  1. Built-in trackpad.
  2. Built in volume control slider.
  3. Dedicated media transport controls.
  4. Nifty dock / recharger stand.

It’s my first Bluetooth device. So far I think Bluetooth works a lot better than IR, because you don’t have to point it at an IR receiver.

The diNovo does have some flaws:

  • No key backlighting, which makes it hard to use in the dark.
  • The mouse buttons below the trackpad are mushy and hinged at the outer edges, making them hard to press. (Happily tapping works and there is a separete left-mouse-button on the left edge of the keyboard. So for typical Mac usage you don’t need to use the mushy buttons.)
  • A skim of the Logitech support forums indicates that the function keys are not as programmable as some people wish. I don’t use function keys that much so this hasn’t been an issue for me yet.

My TV is a 40” LCD, and I sit about 15 feet away from it. At this distance the 1920 x 1280 desktop is just too high resolution for my eyes, so I reduced my screen resolution to 1366 x 720. That seems to work well for now. Apparently I need to get a bigger TV :-)

Using a keyboard/trackpad instead of a button- based remote control is nice. I like being able to use all the ordinary apps that I already know how to use, rather than have to learn a new set of apps and UI commands. I also like not having to switch input devices depending upon what I’m trying to do. (For example if I want to use a web browser to look up some fact about a video that I just watched, it just works.)

The diNovo is very smartly designed, so that it’s easy to use the mouse while holding the keyboard in two hands. Of course I’m a right hander. A left hander might have a different opinion, as the trackpad is located where it can be used easily with the right hand, but not the left hand.

What about Linux?

I have been able to use the same keyboard with both Mac and Kubuntu 9.04. With Kubuntu there were some issues around the initial pairing: You need a working keyboard and mouse in order to pair a new Bluetooth device. You even need to reboot once, and answer one final dialog box using a working keyboard / mouse, before the new device pairing is complete.

A second issue for HTPC use is that the Mac Mini video driver on Kubuntu does not have the flexability to slightly lower the resolution of the screen. I blame Intel for this, as they are in the middle of converting to a new driver model and their current drivers are pretty bare bones.

One final issue for dual booting Mac systems is that it seems to take a while for the keyboard to reconnect after a restart. This is an issue if you have reFit installed and you’re trying to send keystrokes to reFit during the reboot. I found I had to press multiple keys multiple times until reFit started recognizing keys, after which the keyboard acted normally.

Larrabee Instruction Set Talks


Here’s the first public version of the slides from Tom Forsyth and Michael Abrash’s GDC 2009 talks on Larrabee’s instruction set, by way of Japanese magazine PC Watch, as seen on Beyond 3D’s Forums. (You have to manually click on each of the little thumbnails of each slide.):

Larrabee Instruction Set

Hopefully Intel (or GDC) will release a better version of these slide decks sometime soon.

Say, was it just me, or was blogging really light about GDC this year? In past years I was a lot more technical writeups than I saw this year. I wonder if blogging is down in general? Is everyone on Facebook and Twitter now? I can’t imagine Twitter being very useful for reporting technical information.

Here’s Michael Abrash’s Doctor Dobbs Journal article on the Larrabee instruction set.

Dr. Dobbs Larrabee

Here’s the Intel GDC 2009 Larrabee talks:

Rasterization on Larrabee: A First Look at the Larrabee New Instructions (LRBni) in Action SIMD Programming on Larrabee: A Second Look at the Larrabee New Instructions (LRBni) in Action

Using XBMC on Mac Mini using both OSX and Linux

The Xbox Media Center (XBMC) is a nifty open-source application for watching videos. It was originally designed for use on modified Xbox video game consoles, but has more recently become popular for Intel-based Home Theater Personal Computers. It has been ported to Windows, Mac, and Linux. It has no PVR features, instead it concentrates on displaying streaming and downloaded videos. Its big advantage over using the Xbox 360’s similar application is that it handles a much wider variety of streaming video sources and downloaded video codecs.

I’ve been running Plex, an OSX- specific version of the Xbox Media Center, on my Mac Mini for several months now. Overall it’s a good product, but I had some issues for my application. I wanted Plex to serve as a consumer electronic device that my mother-in-law (who doesn’t use computers and can’t read English) could use by herself to watch videos. The system I put together didn’t work very well for her. The problems we ran in to were:

1) The integration with the 6-button Apple Remote Control into the Plex/XBMC UI leaves a lot to be desired. The XBMC UI was designed to be used with a full-featured remote, and the Apple Remote mapping is just too hard to use. My mother-in-law would end up in the weeds of some obscure corner of the Plex UI, without knowing how she had gotten there or how to get back. The Plex software contributed to this problem by having a very sluggish interface to the Apple Remote, that frequently missed clicks. When you couple this with the overloading of “short” and “long” presses to try and give the Apple Remote more logical buttons, it became quite difficult (even for me) to reliably drive the UI. Even a task as simple as backing out of a playing video was difficult to do reliably.

2) OSX (and Plex) have trouble running in consumer-electronics mode, without a keyboard or mouse. OSX and Plex both liked to bring up modal dialogs to report errors or software updates. I was always having to drag out a keyboard and mouse to dismiss these dialogs.

Now, a sensible person would work around these issues by buying a Bluetooth keyboard and mouse, and software like “Remote Buddy” that enables the use of a full-featured remote. A somewhat more ambitious person might have rescripted the Plex UI to work better with the Apple Remote, or even dug into the sources to try and fix the sluggish event problem. But I’m restless, and wanted an excuse to try out Linux on the Mac Mini anyway. So this week I decided to see if the Linux version of XBMC worked any better.

Installing Linux XBMC

Installing Linux is alot like the old pre-Windows 95 days of DOS. I spent a lot of time trying different things and fiddling with hardware issues. Here’s what finally worked for me:

So far (one day) this has worked well. The full-functioned remote control make a big difference in usability.

Some issues I ran into

Ubuntu 9.04 beta problems with OpenGL accelleration for the Mac Mini

The Ubuntu 9.04 beta Intel 945 OpenGL driver does not hardware accelerate as many features of OpenGL as in older versions of Ubuntu. XBMC’s user interface runs very slowly. This is not XBMC-specific. Try using apt-get to install the “amoeba” OpenGL demo. It runs smoothly on Ubuntu 8.10, but is a 2-frame-per-second slide-show on Ubuntu 9.04 beta. I hope this regression gets fixed in future versions of Ubuntu 9.04, as it otherwise looks like a good system.

The prebuilt “PPA” XBMC binaries will crash on Ubuntu 8.10 when pausing video

I had to build XBMC from the subversion sources in order to fix a bug where pausing a video would immediately cause XBMC to crash. (I used a build from Thursday March 26th. I’m sorry but this is the first time I’ve used subversion, so I don’t know how to figure out which revision number I’m synced to.) This is a bug that’s been reported several times in the XBMC forums. It seems to be solved by compiling from source, without making any other changes. I’m suspicious that this may be due to some subtle difference between the libraries that you install to compile and the libraries that are installed when you install the prebuilt binary. (But that’s just a guess. The real reason may be something completely different.)

Well, after all this the system seems to work pretty well for my application. Too bad my mother-in-law’s finished her visit with us and gone back home. At least now I’ve got plenty of time to work out the bugs before her next visit.

[Revision notes]

3/27/09 - Updated for Ubuntu 9.04 beta.

Intel describes Larrabee instruction set

Perhaps in preparation for Friday’s GDC talks by Michael Abrash and Tom Forsyth, Intel has described the Larrabee instruction set:

Prototype Primitives Guide

Intel includes a C source file that implements their new instruction set, so people can play around with the instructions before Larrabee ships.

The instruction set looks alot like a typical GPU shader instruction set. Lots of “log” and “rsqrt” type instructions. But there are also some interesting variations on MADD, such as MADD233_{PI,PS}, which I assume help shave cycles off of inner loops. The compress and expand instructions also look very useful. I look forward to reading code examples from Abrash and Forsyth in the near future!

Listening to my home music at work with SqueezeCenter and Softsqueeze

For some time I’ve wanted to listen to my home music collection on my computer at work. I tried a bunch of different approaches, and finally came up with one that works pretty well:

The resulting system works pretty well. In case you’re wondering, the SqueezeCenter program’s main use is to serve music to the Squeezebox brand of internet radios. The ability to use it with a regular computer, without purchasing a Squeezebox internet radio, is a nice gesture on the part of the Logitec company that makes and sells Squeezebox internet radios.

Future for cryptic Larrabee news

Phil Taylor, a long-time Microsoft graphics and gaming evangelist is now working for Intel on graphics tools evangelism. He started a blog, called Future GPU, where he drops hints and links about Larrabee development. He also tells Microsoft war stories for people in the mood for inside-baseball information about Microsoft’s DirectX and game groups.

Back when I was working at WebTV and just learning about the 3D graphics world, Phil was nice enough to give me and a few of my WebTV co- workers tickets to the super-desirable GDC DirectX party. These parties were intended for external developers, so it was very hard for non-DirectX Microsofties to attend. Thanks Phil!!! :-)

From reading Phil’s blog it sounds like Intel’s developing a set of graphics debugging tools that they’re going to announce at GDC. Could it be PIX-for-Larrabee?

I found Phil’s site through a “Google Alert” that I set up for Larrabee news. It does a weekly search for Larrabee news. The web’s so big and sparsely connected that I’m finding that I’ve never heard of any of the web sites that the Alert is dredging up. Most of the sites mentioned in the Google Alert are not worth visiting, but a few (like Phil’s site) are very interesting indeed.

Pixar Quality Graphics is 720 Gflops

For at least 10 years GPU vendors have been talking about “Pixar Quality” graphics. But what does that mean? Well, according to this lecture on The Design of Renderman, the original goals for the REYES architecture were

  • 3000 x 1667 pixels (5 MP)
  • 80M Micropolygons (each 1/4th of a pixel in size, depth complexity of 4)
  • 16 samples per pixel
  • 150K geometric primitives
  • 300 shading flops per micropolygon
  • 6 textures per primitive
  • 100 1MB textures

That’s a shading rate of 80M * 300 * 30 Hz = 720 Gflops. (They were probably more concerned about 24 Hz, but for games 30Hz is better.)

In comparison I think the peak shader flops of high-end 2008-era video cards are in the 1 TFlop range. (Xbox 360 Xenos is 240 Gflops, PS3 is a bit less.). Now, GPU vendors typically quote multiply-accumulate flops, because that doubles the number of flops. So it’s more realistic to say that 2008-era video cards are in the 500 Gflop range. So we really are entering the era of “Pixar Quality” graphics.

Tech Talk on Wii security model (and breaking it)

A very thorough talk describing the Nintendo Wii game console security model and the bugs and weaknesses that allowed the Wii to be compromised: Console Hacking 2008: Wii Fail

In a nutshell, security is provided by an embedded ARM CPU that sits between the CPU and the IO devices, and handles all the IO. The two main flaws were (a) A bug in the code that compared security keys, such that it was possible to forge security keys, and (b) secret break-once-run-everywere information was stored un-encrypted in RAM, where it could be extracted using hardware modifications.

There’s a nice table at the end of the presentation showing a number of recent consumer devices, what their security model was, and how long it took to break them.

The PS3 is the only console that’s currently unbroken. The PS3’s security model seems similar to the Xbox 360, but somewhat weaker. But it remains unbroken. This seems to due to the existence of an official PS3 Linux port, which means most Linux kernel hackers are not motivated to hack the PS3 security. (Only the ones who want full access to the GPU from Linux are motivated, and only to the extent that they can access the GPU.)