On 3/16/16, 2:32 AM, "linux-arm-kernel on behalf of Ganesh Mahendran" <linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx on behalf of opensource.ganesh@xxxxxxxxx> wrote: >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. Is there any explanation why is this so? May be there is an alternative to this, apart from reverting the commit. Until now it seems L1_CACHE_SHIFT is the max of supported chips. But now we are making it 64byte, is there any reason why not 32. Thanks, Tirumalesh. > >Cc: stable@xxxxxxxxxxxxxxx >Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx> >--- > 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 > > >_______________________________________________ >linux-arm-kernel mailing list >linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ��.n��������+%������w��{.n�����������ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f