Eric Lee / smarc-fsl-linux-kernel

01 Sep, 2015

1 commit

  • 0e833e697   md/raid6: delta syndrome for ARM NEON ... Browse Code »

    This implements XOR syndrome calculation using NEON intrinsics.
    As before, the module can be built for ARM and arm64 from the
    same source.

    Relative performance on a Cortex-A57 based system:

    raid6: int64x1 gen() 905 MB/s
    raid6: int64x1 xor() 881 MB/s
    raid6: int64x2 gen() 1343 MB/s
    raid6: int64x2 xor() 1286 MB/s
    raid6: int64x4 gen() 1896 MB/s
    raid6: int64x4 xor() 1321 MB/s
    raid6: int64x8 gen() 1773 MB/s
    raid6: int64x8 xor() 1165 MB/s
    raid6: neonx1 gen() 1834 MB/s
    raid6: neonx1 xor() 1278 MB/s
    raid6: neonx2 gen() 2528 MB/s
    raid6: neonx2 xor() 1942 MB/s
    raid6: neonx4 gen() 2888 MB/s
    raid6: neonx4 xor() 2334 MB/s
    raid6: neonx8 gen() 2957 MB/s
    raid6: neonx8 xor() 2232 MB/s
    raid6: using algorithm neonx8 gen() 2957 MB/s
    raid6: .... xor() 2232 MB/s, rmw enabled

    Cc: Markus Stockhausen
    Cc: Neil Brown
    Signed-off-by: Ard Biesheuvel
    Signed-off-by: NeilBrown

    Ard Biesheuvel
     

22 Apr, 2015

1 commit

  • fe5cbc6e0   md/raid6 algorithms: delta syndrome functions ... Browse Code »

    v3: s-o-b comment, explanation of performance and descision for
    the start/stop implementation

    Implementing rmw functionality for RAID6 requires optimized syndrome
    calculation. Up to now we can only generate a complete syndrome. The
    target P/Q pages are always overwritten. With this patch we provide
    a framework for inplace P/Q modification. In the first place simply
    fill those functions with NULL values.

    xor_syndrome() has two additional parameters: start & stop. These
    will indicate the first and last page that are changing during a
    rmw run. That makes it possible to avoid several unneccessary loops
    and speed up calculation. The caller needs to implement the following
    logic to make the functions work.

    1) xor_syndrome(disks, start, stop, ...): "Remove" all data of source
    blocks inside P/Q between (and including) start and end.

    2) modify any block with start
    Signed-off-by: NeilBrown

    Markus Stockhausen
     

09 Jul, 2013

1 commit

  • 7d11965dd   lib/raid6: add ARM-NEON accelerated syndrome calculation ... Browse Code »

    Rebased/reworked a patch contributed by Rob Herring that uses
    NEON intrinsics to perform the RAID-6 syndrome calculations.
    It uses the existing unroll.awk code to generate several
    unrolled versions of which the best performing one is selected
    at boot time.

    Signed-off-by: Ard Biesheuvel
    Acked-by: Nicolas Pitre
    Cc: hpa@linux.intel.com

    Ard Biesheuvel