Intel Develops Linux 'Software GPU' That's ~29-51x Faster (phoronix.com)

An anonymous reader writes: Intel is open-sourcing their work on creating a high-performance graphics software rasterizer that originally was developed for scientific visualizations. Intel is planning to integrate this new OpenSWR project with Mesa to deploy it on the Linux desktop as a faster software rasterizer than what's currently available (LLVMpipe). OpenSWR should be ideal for cases where there isn't a discrete GPU available or the drivers fail to function. This software rasterizer implements OpenGL 3.2 on Intel/AMD CPUs supporting AVX(2) (Sandy Bridge / Bulldozer and newer) while being 29~51x faster than LLVMpipe and the code is MIT licensed. The code prior to being integrated in Mesa is offered on GitHub.

Comments

Re:How does it compare to a low-end graphics card?

[edxwelch]

Even more interesting question, how does something like Half-Life run on it? Is it a slide show, or is it playable?

Re:How does it compare to a low-end graphics card?

[TheRaven64]

I've not tried it, but to give a few data points:

I have a slow AMD E-350 (1.6GHz, dual core, low power chip) in the machine I use as a media centre. With the original MESA software fallback, I got about 3 frames per second in the UI. It was totally unusable. After FreeBSD gained support for the GPU, I tried it again and got about 20-30fps. This seemed a bit low, and I discovered that I'd misconfigured it and it was still using the software fallback, only now it was using LLVMPipe. I don't know how much faster the GPU actually is, because at 60fps it hits vsync and doesn't try to go faster, though CPU usage drops from 100% to around 10% (of one core). Of course, this CPU doesn't have AVX, so won't benefit from this code.

The release announcement has a couple more details. This new back end is optimised for workloads with large vertex counts but simple shaders and for machines with a lot of cores. There are a lot of ways that you can make OpenGL shaders faster if you're optimising for the simple case. Half Life 1 works on a fixed-function pipeline, so should be fast on this. Half Life 2 uses a bit more by way of shaders, but possibly not enough to cause it to struggle. Stuff that runs well on a GPU is likely to also run well on multiple cores, if you get the synchronisation right, but the existing LLVM pipe uses a single thread.

My main interest in this is whether you can turn off the GPU entirely for normal compositing desktop workloads and whether it will make a big difference to the power consumption if you do. Compositing desktops generally do a lot of simple compositing, but have very simple shaders and quite simple geometry. I'd be very interested to see whether doing this on the AVX pipelines is cheaper than having an entire separate core doing the work, especially given that the GPU core is generally optimised for more complex graphical workloads.