Hi Kiko, On 5 May 2011 15:21, Christian Robottom Reis <k...@linaro.org> wrote: > Hey there, > > I was asked today in the board meeting about the use of NEON > routines in the kernel; I said we had looked into this but hadn't done > it because a) it wasn't conclusively better and b) if better, it would > need to be done conditionally per-platform. But I wanted to double-check > that's actually true (and I'm copying Vijay to keep me honest). I have > some references:
Not quite: a) Neon memcpy/memset is worse on A9 than non-neon versions (better on A8 typically) b) In general I don't believe fpu or Neon code can be used internally to the kernel. Dave > http://lists.linaro.org/pipermail/linaro-toolchain/2011-January/000722.html > > > http://groups.google.com/group/beagleboard/browse_thread/thread/12c7bd415fbc0993/c54dde7b9d55cf99?pli=1 > > http://www.spinics.net/lists/arm-kernel/msg106503.html > > http://dev.gentoo.org/~armin76/arm/memcpy-neon_result.txt > > > https://wiki.linaro.org/WorkingGroups/ToolChain/Benchmarks/InitialMemcpy?highlight=%28memcpy%29 > > https://wiki.linaro.org/WorkingGroups/ToolChain/StringRoutines?highlight=%28memcpy%29 There may be the potential still for non-neon optimised memcpy/memset for Cortex a9; however the kernel routines are pretty good. > Incidentally, this ties into the question sent earlier this week which > had to do with Nico's work item in: > > https://blueprints.launchpad.net/linux-linaro/+spec/other-kernel-thumb2 > > Which IIRC Nico says probably isn't worth it, right? I thought dmart had done a lot of that? Dave _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
