Mesa currently uses swrast, LLVMpipe, and Softpipe drivers as software rasterisers that run OpenGL on the CPU rather than any dedicated GPU. But apparently Intel’s minions have been developing a new, high-performance software rasteriser.
The minions hope to upstream their new “OpenSWR” project into Mesa as offering fast, CPU-rendered graphics.
For those who came in late, OpenSWR is the newly-announced high performance software rasterizer that’s developed at Intel by a different team of minions.
That group was looking at software-defined visualisations and scientific visualisations. Chipzilla already had developed a high-performance software rasteriser internally and then later they decided to engage in this project and work on upstream Mesa3D support.
Writing in its blog, a spokesMinion said that for high geometry workloads the software was faster than llvmpipe.
“This is to be expected, as llvmpipe only threads the fragment processing and not the geometry frontend. The linked slide below shows some performance numbers from a benchmark dataset and application.”
On a 36 total core dual E5-2699v3 there is a performance 29 times to 51 times that of llvmpipe.
“While our current performance is quite good, we know there is more potential in this architecture. When we switched from a prototype OpenGL driver to Mesa we regressed performance severely, some due to interface issues that need tuning, some differences in shader code generation, and some due to conformance and feature additions to the core swr. We are looking to recovering most of this performance back,” the spokesMinion said. Whatever any of that means.
The new rasteriser is being put out under the Mesa MIT license. Intel is making it open-source to and making it easier to deploy. Unlike their Intel i965 Mesa driver, this rasterizer builds atop Gallium3D. Additionally, OpenSWR makes use of LLVM.
The rasteriser should work with AMD CPUs, if it has AVX/AVX2 support. Intel plans on adding AVX512 support as well.