Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755321AbcCRVFn (ORCPT ); Fri, 18 Mar 2016 17:05:43 -0400 Received: from mail-bl2on0084.outbound.protection.outlook.com ([65.55.169.84]:10596 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751059AbcCRVFl (ORCPT ); Fri, 18 Mar 2016 17:05:41 -0400 From: "Chalamarla, Tirumalesh" To: Ganesh Mahendran , "catalin.marinas@arm.com" , "will.deacon@arm.com" CC: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] Revert "arm64: Increase the max granular size" Thread-Topic: [PATCH] Revert "arm64: Increase the max granular size" Thread-Index: AQHRf2q07H5kbo3Bx0+pHW/tbsCLGJ9fP6wA Date: Fri, 18 Mar 2016 21:05:37 +0000 Message-ID: References: <1458120743-12145-1-git-send-email-opensource.ganesh@gmail.com> In-Reply-To: <1458120743-12145-1-git-send-email-opensource.ganesh@gmail.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/0.0.0.160212 authentication-results: gmail.com; dkim=none (message not signed) header.d=none;gmail.com; dmarc=none action=none header.from=caviumnetworks.com; x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [64.2.3.194] x-ms-office365-filtering-correlation-id: 5679d34a-94a1-4b4d-dd60-08d34f710e41 x-microsoft-exchange-diagnostics: 1;BLUPR0701MB1777;5:L380Pao8BSRYiGzLV9CAQ85q2b/koKJkKi5K2o0JcsqAspo2EwXIJByaYhA47lMEF+V+7fJgtYGeyHil5xxVc5CdfC5qCDaEylXj+1m5HiWzWiy29wbZWIg9PTp5BOvmOJ9sTeSp0/wJz461NjjGiQ==;24:P0xWlAKHZDK4IHN4+nlFtez8durADw9fhVUgB00iaEm+psRasnpUeFX0MOnZfreuY4M1WqePKw8TOC4HSZ+Yi8E/VohTJKF+nt8qY/VU+As= x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:BLUPR0701MB1777; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:; x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(601004)(2401047)(8121501046)(5005006)(3002001)(10201501046);SRVR:BLUPR0701MB1777;BCL:0;PCL:0;RULEID:;SRVR:BLUPR0701MB1777; x-forefront-prvs: 088552DE73 x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(6009001)(377454003)(24454002)(164054003)(2900100001)(5004730100002)(87936001)(2950100001)(2201001)(3846002)(102836003)(6116002)(99286002)(83506001)(4001350100001)(15975445007)(82746002)(586003)(83716003)(19580405001)(19580395003)(106116001)(33656002)(10400500002)(50986999)(5001770100001)(77096005)(1096002)(1220700001)(5008740100001)(1720100001)(76176999)(2501003)(189998001)(54356999)(36756003)(11100500001)(5002640100001)(122556002)(81166005)(4326007)(3660700001)(66066001)(92566002)(2906002)(3280700002)(86362001);DIR:OUT;SFP:1101;SCL:1;SRVR:BLUPR0701MB1777;H:BLUPR0701MB1780.namprd07.prod.outlook.com;FPR:;SPF:None;MLV:sfv;LANG:en; spamdiagnosticoutput: 1:23 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: MIME-Version: 1.0 X-OriginatorOrg: caviumnetworks.com X-MS-Exchange-CrossTenant-originalarrivaltime: 18 Mar 2016 21:05:37.4874 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 711e4ccf-2e9b-4bcf-a551-4094005b6194 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLUPR0701MB1777 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id u2IL5m3X028263 Content-Length: 1960 Lines: 68 On 3/16/16, 2:32 AM, "linux-arm-kernel on behalf of Ganesh Mahendran" 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 -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 >--- > 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 > >-#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