LCA14 GWG Day 2

Posted: March 4, 2014 in Uncategorized

Tuesday was yet another day with no sessions hosted by the Graphics Working Group. Wednesday, Thursday Friday are our big days. So for us it was a day of our own meetings and attending working group sessions.

I went to the 64 bit toolchain status meeting. It was good to hear that LLVM’s MCJIT is at least able to pass it’s tests on AARCH64. This is important for future versions of OpenCL for instance on AARCH64. I do wish there was a bit more focus on llvm for AARCH64 tho. With significant projects like Chromium seriously considering a move to llvm it seems wise. 

The next session I went to was the one on SQLite optimization. SQLite is database at the heart of and in very common use across Android, iOS, Linux and so on. It’s an important foundation block so it’s optimization can be valuable. Using the cortex strings work and applying that to SQLite on Android yielded the Linaro Android team some significant results. (20-35%)  The Android use case is an interesting one in that the databases tend to be smaller so while speed is one factor to optimize for, space and battery usage are also important. This work came at it only from the speed angle. It’s still a work in progress so will keep in tune.

Related to that as part of our GPGPU efforts I’m in the midst of optimizing SQLite with OpenCL. I’m at the stage of writing the OpenCL kernels so it’s too early to start talking about microbenchmark results. I’m also aiming at a slightly different use case. I’m looking at more sizable databases and more common operations that would be found with use as part of a LAMP or LAMP-like stack. I’ll be talking about this effort as part of the GPGPU session on Thursday.

During the afternoon hacking time, I was in solid meetings all day. This is the life of a tech lead sometimes. While it would be great to be heads down in vi this week, doing so would look out in many wonderful opportunities to talk to many people.

On Tuesday about 1/2 of GWG and the LHG got together and were talking about a variety of topics. Mostly at an architectural level and some of the factors that go into making good technology choices when it comes to video playback and so on. As LHG gets off the ground they have a number of interesting (and fun!) challenges ahead of them.

The Media and Libs subteam got together and we held a project review. This is a perfect activity for connect. It is quite good to perform detailed reviews from time to time. The good news is that the libvpx (VP8 &VP9), libjpeg-turbo and pixman optimization efforts for AARCH64 are coming along quite well with patches flowing upstream. Today (Wednesday) we’ll be meeting to set the next list of libs that we will optimize for AARCH64.

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