Last week I put out new numbers showing the LLVMpipe performance with the latest Gallium3D code found in Mesa 7.9-devel. This Gallium3D driver accelerates all operations on the CPU rather than a GPU as a better software rasterizer than what is currently available for Linux, but even with a hefty Intel Core i7 CPU the OpenGL acceleration was still quite slow. In this article using an Intel Core i3 mobile CPU we are looking at the LLVMpipe performance again, but this time comparing it to the Intel graphics performance and also looking at the impact that the clock frequency and Hyper Threading have on this Gallium3D driver that heavily utilizes the Low-Level Virtual Machine for its CPU optimizations.
For running the LLVMpipe driver this time around we have an ASRock Core 100HT NetTop that we are currently reviewing. This NetTop is not Atom-based but has an Intel Core i3 330M CPU (clocked at 2.13GHz by default, dual-core plus Hyper Threading), an ASRock HM55-HT motherboard, Intel Core IGP graphics, 4GB of system memory, and a 500GB Seagate ST9500325AS SATA HDD. Installed onto this Core i3 system was an Ubuntu 10.10 snapshot with the Linux 2.6.35-6-generic x86_64 kernel, GNOME 2.30.2, X.Org Server 1.8.2 RC2, LLVM 2.7, and an EXT4 file-system. For Gallium3D/LLVMpipe testing we pulled from the Mesa master repository on 2010-06-28 of the latest Mesa 7.9-devel code.
In looking again at LLVMpipe's performance we tested this Gallium3D CPU driver at its stock speed of 2.13GHz and Hyper Threading enabled (a total of four logical cores), then again when the Intel Core i3 was overclocked to 2.6GHz but with Hyper Threading enabled, and then lastly at 2.6GHz but with Hyper Threading re-enabled. We also benchmarked the Intel DRI driver on classic Mesa (since Intel is not backing a Gallium3D driver at this time) when the CPU was at its stock 2.13GHz + HT. The games we used for testing were OpenArena and Warsow.
LLVMpipe lost by a wide margin to the Gallium3D ATI R300 and Nouveau drivers with real graphics hardware in our previous testing and today's tests show that even LLVMpipe cannot beat out the classic Intel Mesa driver even with Intel's IGPs not being the best hardware. At 640 x 480 with this Intel Core i3 CPU the Intel graphics were about twice as fast as LLVMpipe. Our different LLVMpipe test scenarios do show that LLVMpipe is taking advantage of multiple cores and did have a slight boost attributed to enabling Intel Hyper Threading that doubled the core count, but the clock speed seemed to have a slightly greater impact on the overall performance.