From: "Chalamarla, Tirumalesh" <Tirumalesh.Chalamarla@caviumnetworks.com>
To: Ganesh Mahendran <opensource.ganesh@gmail.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"will.deacon@arm.com" <will.deacon@arm.com>
Cc: "stable@vger.kernel.org" <stable@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] Revert "arm64: Increase the max granular size"
Date: Fri, 18 Mar 2016 21:05:37 +0000 [thread overview]
Message-ID: <DA22064C-45A7-4F79-A433-84054AF182DF@caviumnetworks.com> (raw)
In-Reply-To: <1458120743-12145-1-git-send-email-opensource.ganesh@gmail.com>
On 3/16/16, 2:32 AM, "linux-arm-kernel on behalf of Ganesh Mahendran" <linux-arm-kernel-bounces@lists.infradead.org on behalf of opensource.ganesh@gmail.com> 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@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
>
>
>_______________________________________________
>linux-arm-kernel mailing list
>linux-arm-kernel@lists.infradead.org
>http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2016-03-18 21:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-16 9:32 [PATCH] Revert "arm64: Increase the max granular size" Ganesh Mahendran
2016-03-16 10:07 ` Will Deacon
2016-03-16 13:06 ` Timur Tabi
2016-03-16 14:03 ` Mark Rutland
2016-03-16 14:35 ` Will Deacon
2016-03-16 14:54 ` Mark Rutland
2016-03-16 14:18 ` Catalin Marinas
2016-03-16 15:26 ` Timur Tabi
2016-03-17 14:27 ` Catalin Marinas
2016-03-17 14:49 ` Timur Tabi
2016-03-17 15:37 ` Catalin Marinas
2016-03-17 16:03 ` Marc Zyngier
2016-03-17 18:07 ` Andrew Pinski
2016-03-17 18:34 ` Timur Tabi
2016-03-17 18:37 ` Catalin Marinas
2016-03-18 21:05 ` Chalamarla, Tirumalesh [this message]
2016-03-21 1:56 ` Ganesh Mahendran
2016-03-21 17:14 ` Catalin Marinas
2016-03-21 17:23 ` Will Deacon
2016-03-21 17:33 ` Catalin Marinas
2016-03-21 17:39 ` Chalamarla, Tirumalesh
[not found] ` <CAPub14-sFgx=oCHzJPb9h9b_V0rbn5UAMDNJ-yTkjhz38JPqMQ@mail.gmail.com>
[not found] ` <10fef112-37f1-0a1b-b5af-435acd032f01@codeaurora.org>
2017-04-06 7:22 ` Imran Khan
2017-04-06 15:58 ` Catalin Marinas
2017-04-07 2:06 ` Ganesh Mahendran
2017-04-07 8:59 ` Catalin Marinas
2017-04-12 5:13 ` Imran Khan
2017-04-12 14:00 ` Chalamarla, Tirumalesh
2017-04-17 7:35 ` Imran Khan
2017-04-17 10:38 ` Sunil Kovvuri
2017-04-18 14:48 ` Catalin Marinas
2017-04-18 17:05 ` Sunil Kovvuri
2017-04-19 12:01 ` Catalin Marinas
2017-04-19 13:11 ` Sunil Kovvuri
2017-04-25 6:42 ` Ding Tianhong
2017-04-18 18:21 ` Chalamarla, Tirumalesh
2017-04-11 4:40 ` Jon Masters
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