lkml.org 
[lkml]   [2016]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] Revert "arm64: Increase the max granular size"
    Date
    Reverts commit 97303480753e ("arm64: Increase the max granular size").

    The commit 97303480753e ("arm64: Increase the max granular size") will
    degrade system performente in some cpus.

    We test wifi network throughput with iperf on Qualcomm msm8996 CPU:
    ----------------
    run on host:
    # iperf -s
    run on device:
    # iperf -c <device-ip-addr> -t 100 -i 1
    ----------------

    Test result:
    ----------------
    with commit 97303480753e ("arm64: Increase the max granular size"):
    172MBits/sec

    without commit 97303480753e ("arm64: Increase the max granular size"):
    230MBits/sec
    ----------------

    Some module like slab/net will use the L1_CACHE_SHIFT, so if we do not
    set the parameter correctly, it may affect the system performance.

    So revert the commit.

    Cc: stable@vger.kernel.org
    Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
    ---
    arch/arm64/include/asm/cache.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
    index 5082b30..bde4499 100644
    --- a/arch/arm64/include/asm/cache.h
    +++ b/arch/arm64/include/asm/cache.h
    @@ -18,7 +18,7 @@

    #include <asm/cachetype.h>

    -#define L1_CACHE_SHIFT 7
    +#define L1_CACHE_SHIFT 6
    #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)

    /*
    --
    1.7.9.5
    \
     
     \ /
      Last update: 2016-03-16 11:41    [W:2.514 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site