1. 20 Mar, 2018 1 commit
    • Matt Brown's avatar
      lib/raid6/altivec: Add vpermxor implementation for raid6 Q syndrome · 751ba79c
      Matt Brown authored
      This patch uses the vpermxor instruction to optimise the raid6 Q
      syndrome. This instruction was made available with POWER8, ISA version
      2.07. It allows for both vperm and vxor instructions to be done in a
      single instruction. This has been tested for correctness on a ppc64le
      vm with a basic RAID6 setup containing 5 drives.
      
      The performance benchmarks are from the raid6test in the
      /lib/raid6/test directory. These results are from an IBM Firestone
      machine with ppc64le architecture. The benchmark results show a 35%
      speed increase over the best existing algorithm for powerpc (altivec).
      The raid6test has also been run on a big-endian ppc64 vm to ensure it
      also works for big-endian architectures.
      
      Performance benchmarks:
        raid6: altivecx4 gen() 18773 MB/s
        raid6: altivecx8 gen() 19438 MB/s
      
        raid6: vpermxor4 gen() 25112 MB/s
        raid6: vpermxor8 gen() 26279 MB/s
      Signed-off-by: default avatarMatt Brown <matthew.brown.dev@gmail.com>
      Reviewed-by: default avatarDaniel Axtens <dja@axtens.net>
      [mpe: Add VPERMXOR macro so we can build with old binutils]
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      751ba79c
  2. 14 Mar, 2018 6 commits
  3. 13 Mar, 2018 33 commits