From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752216AbcDEA1t (ORCPT ); Mon, 4 Apr 2016 20:27:49 -0400 Received: from mail-db5eur01on0067.outbound.protection.outlook.com ([104.47.2.67]:21316 "EHLO EUR01-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751039AbcDEA1s (ORCPT ); Mon, 4 Apr 2016 20:27:48 -0400 Authentication-Results: vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=none action=none header.from=mellanox.com; Subject: Re: [PATCH] nohz_full: Make sched_should_stop_tick() more conservative To: Rik van Riel , Frederic Weisbecker , Christoph Lameter , Ingo Molnar , Luiz Capitulino , Peter Zijlstra , Thomas Gleixner , Viresh Kumar , References: <1459539771-4251-1-git-send-email-cmetcalf@mellanox.com> <1459797143.6219.22.camel@redhat.com> <5702C126.1030904@mellanox.com> <1459798571.6219.23.camel@redhat.com> From: Chris Metcalf Message-ID: <57030672.8080405@mellanox.com> Date: Mon, 4 Apr 2016 20:27:30 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1 MIME-Version: 1.0 In-Reply-To: <1459798571.6219.23.camel@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [173.76.23.146] X-ClientProxiedBy: BLUPR07CA0045.namprd07.prod.outlook.com (10.255.223.158) To AM4PR05MB1683.eurprd05.prod.outlook.com (10.165.245.154) X-MS-Office365-Filtering-Correlation-Id: 8d8963e5-1d23-42f4-a301-08d35ce91b9c X-Microsoft-Exchange-Diagnostics: 1;AM4PR05MB1683;2:c9aCIOQG3VrLdMgP3TWEp0thZxkyqYqOC6ObJLBdP5kKouoNN8mEvDJvhNYCQyVYJ4mCIxhtNnO9y6fKpz/3U46UoHHpirttfXFEAXxLfWck2VLIXUD4uB4Fs7vz6JBQTk8+gUHV46d+a721CsNavY6bmbf6ZjR1hmuxR2R5xRKQIotUEhoAKOIaLYkMVkiL;3:iSLweaubRF1ae19zUAXn1FGVGJDDZDk2KeLGJywxgzTcZTftsAglw1mM5LKbVc3a6Yqm96yi6/qI/ejbQ/8Ny0uGh8vLf4jVR8aZoHuDsnBK7wC5CfH6Xh+rqSo0VQbz;25:oBLNCNp5Xccz3ogdfOsXbD2WkCcGLRFyN5axjZp8LJSgE58V2eXCIWTosAhjSy98NdwuVrrNBasN5kBtprOZYzKM4VuESowDSwcK/4UIEWwfxesIhRhY76+vuPzXvqXhhccBaGgCSH/3JBtVmxE3K5mNSgup9YqR84jBCkMXfy7TeOtU4TNOEZWQlI9sToQ6N705D959mozbW6e/RSq/+ZZarYzROj5yKkJOyH+7X9acXHXsGpexVbXNN8XeIR6cUuXYF1EBUQIUYuy3rlJKUlzOjEE8vO1G6kB2Z04UnKlR49+nyYCxFy6I75s572n507XRpjILK5pYCabUhsaWpS67QU7eHUQi42zASP8z6fo= X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:AM4PR05MB1683; X-Microsoft-Exchange-Diagnostics: 1;AM4PR05MB1683;20: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;4:2+dOqM8egCXzCie1DT61HHPoGKj70I7Ik5NmhhJtai1x+VRbg/vsfDK+N+XKjTDVcHka6urAwyAX0yuOFmCL+qKZSC7jDkmT7etSS91GRqm4Mj+8QSWFqyQ/US5wRUGGt0IU0przhLhdjXqXURsPvferFCKGi04922YNePBZP5Tz5A/bywruq3qdO/ILs7NZy7C/V9XnI7eNBlnjT3vqgF4Gcc5TI1d+ajiZeANKghKg/BmdCKz+MmKob12E5YLtOUw3NqccRfEm+ePfEXY+xwXRDtO+xvm42Jcq9sQN3GN9VUkiBwHlcLamXCzpVmF6thZOpM8Tm/SOHDoNgKTxZaklqbWxymxAJSaWEkMGFX85BCgrP6sMacyaVK9GeQPT X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(5005006)(8121501046)(3002001)(10201501046);SRVR:AM4PR05MB1683;BCL:0;PCL:0;RULEID:;SRVR:AM4PR05MB1683; X-Forefront-PRVS: 0903DD1D85 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(4630300001)(6049001)(6009001)(24454002)(377454003)(377424004)(122286003)(36756003)(81166005)(117636001)(2906002)(1096002)(117156001)(59896002)(586003)(3846002)(19580405001)(19580395003)(93886004)(230700001)(50986999)(65816999)(83506001)(5008740100001)(54356999)(76176999)(87266999)(47776003)(6116002)(77096005)(2950100001)(23676002)(15975445007)(66066001)(42186005)(189998001)(5004730100002)(107886002)(99136001)(86362001)(4001350100001)(5001770100001)(64126003)(92566002)(50466002)(62816006)(18886065003);DIR:OUT;SFP:1101;SCL:1;SRVR:AM4PR05MB1683;H:[192.168.1.158];FPR:;SPF:None;MLV:sfv;LANG:en; X-Microsoft-Exchange-Diagnostics: =?utf-8?B?MTtBTTRQUjA1TUIxNjgzOzIzOjR3YWl1RWpiMm1nMHdKVmRoczFYa2ZkOUZB?= =?utf-8?B?byt0Q0NqUnNTYUhSUkdlWDJTdEFLYXZVTU51UTczRGpJa1E2MnNuWGpuQUNM?= =?utf-8?B?ZUUrVEQyR1hLZW5nN2RmUjJxdFhCdjRKS3JYQlM1VElLYk9FWFhhbTdlYUU3?= =?utf-8?B?MEY1Nzk2VDczREVWRTFTSkl1cmU4TkFGdnNLeEdldTM2TGZRNjBXbHFpanRU?= =?utf-8?B?Y0hTZXZ6Q2VDaUxyVUFTUzE2ZFkzNjhLd0R1bmkrR2QyNzFHOS82TGJaOGxG?= =?utf-8?B?dTZCUjVBalg4RGthYzl4K242eUdQaml1Ty9qZGNhc1pMSjJ5T0dVcGt3Tnl3?= =?utf-8?B?TmFGQkgyV3V2a3AyT0hzSm4wZnVsaHppbWQ1a2xxOUp5N2hCSzFHMHUvdkdJ?= =?utf-8?B?cE53bkZTbzkzSVBSdEp1dEdtWU9EVlQvZVZvSjRha3ZNZDRPNGpxM0U2cTRl?= =?utf-8?B?cWlaNTJLd2pwTkVub1NlMW5UVkErK0krWFplK0Fwd09kalh3NVB4dEZnK05w?= =?utf-8?B?aEhiTzVTS2RNYzZtNWt3S1RTdFNRTERtem5YNWU4WVNCM25RNjg5SGtBWWs3?= =?utf-8?B?YzlWRklOMnRpNG9tWjhyb3RjS2VRT0FMbjhqMzFpUkpiSG5UQ0tqRFhUK1hN?= =?utf-8?B?L0RtZFVEb00vSUZxMVlzTlNrcjhDZnVNazEwdVNlK3J4WVNsbFA0TStJYW10?= =?utf-8?B?eEZQeGswc0E4NnNxbUh3ZVBZOHhhNkRaMlJmdEJNb2wrL0ZodS94R25EL3Zs?= =?utf-8?B?WHpiQlozbU91Y0kwMzRYNjQ3Qmk1MVlmOE9aL1dLNEwrL1FnUnpOa3pSS2Rh?= =?utf-8?B?UE5qd0tabnNMS0FzbVducXVRY0J0eDZMSTVlUVRuTncvc0FkajRvME9IT3ha?= =?utf-8?B?eFB5cUhkM3AwM3FCaDJHZ1l1NGxDUVJRVGVMM0laYXB0MEhZR1psSHpPa0E2?= =?utf-8?B?Z0FGem5BMlFUZmVqNVhVNDM0WWR2Z0tKa0xvWk1pZ3EzdkVEVVhGTnAxSGN1?= =?utf-8?B?U0lsQTZvRmNLUkhwUnhRVTUzeHp5MUx3Y2ZtMzh0dlV3SVhKTU5kZHFMZlNs?= =?utf-8?B?YmVzQnV4WVh2MkwrTEtJWWRMZzk0QkQwM1NmcCtCTks0UkpuWTVmdjg1d2ZV?= =?utf-8?B?M2ozT3dTNnJ2c01WRGRwN1JaWHpLeGViTnhOSjdldVBNenFFWkVRZlgxdXE0?= =?utf-8?B?a3BNVWkrV29NVDVYZVBmZ2pubGNnMDlhYWp2T2JsME5HemJXcktzVlc4Q2pV?= =?utf-8?B?WDI3M1FlRGt3SUVtczJZN0dhY3NQZzEvQXU5MjZxREo1VDM0aCtaVGZ5S0Fs?= =?utf-8?B?Y0xjYzd1L3dRYmF2dVN4SGhhSW5nbHJ5eTNWQk1MMnh0NElSUFJzT1lDZTEx?= =?utf-8?B?elB4M0FPWmRDTC9leTlMYXJkNWFQdU10TmVlRFozN2xxcU80QXJTaWJoK1Yy?= =?utf-8?B?L2xsSitKVHVxNHZFWVBnTWhyOFRhdUpwVVpXM2tEK3pUcGJOR2V1QzNqaFlY?= =?utf-8?B?K3N2bTluMXk3Q2FsZmpNUlliZ3I0cG1QQ1BITnRqWWpWeVNPYys5VDNyaDFv?= =?utf-8?B?TkozUHQzb1hQbjZLQXBjcFlsZTdtWXdaaEk4anp6dHp4blhrbmc5QmJGRmVw?= =?utf-8?B?Q1I2NmtyQUdYZVErYk81MEN3elMxKysxeGRRZm9NbWVkaERtbHFJenBBN3dr?= =?utf-8?Q?4WZ9Ng80zrYqNDLXAc=3D?= X-Microsoft-Exchange-Diagnostics: 1;AM4PR05MB1683;5:+jI7pptNKN9r4fygKRRW2varHlMDdjtgOj6a3DJct+E7jaE+dRzNIWBX2KnyQJyyBYyze2px++/XL5+xZ3c6NTTDapO8NYQHpx7ehD8YX/AHkXA7hLjNEHhMs1CAGwHr4XHmwP5G2+d2uqd7SPC57A==;24:GZ3881KEkSqWnHVTADCpfebksOrtHTGG7JKONVmuCSPhC5G3xbvvqt7ecmUW9uZ+6CqCxfSywZZvoHs7lOnSSrDMnMzS3UYrJW7CVPknA2A= SpamDiagnosticOutput: 1:23 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: Mellanox.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Apr 2016 00:27:43.0381 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM4PR05MB1683 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/4/2016 3:36 PM, Rik van Riel wrote: >>> On Fri, 2016-04-01 at 15:42 -0400, Chris Metcalf wrote: >>>> On arm64, when calling enqueue_task_fair() from >>>> migration_cpu_stop(), >>>> we find the nr_running value updated by add_nr_running(), but the >>>> cfs.nr_running value has not always yet been >>>> updated. Accordingly, >>>> the sched_can_stop_tick() false returns true when we are >>>> migrating a >>>> second task onto a core. >>>> Correct this by using rq->nr_running instead of rq- >>>>> cfs.nr_running. >>>> This should always be more conservative, and reverts the test to >>>> the >>>> form it had before commit 76d92ac305f2 ("sched: Migrate sched to >>>> use >>>> new tick dependency mask model"). >>>> >>>> > [...] > > Patch gets my: > > Acked-by: Rik van Riel Thanks! Whose tree should this go through: Frederic, PeterZ, Ingo? Do any of you have any concerns with it? -- Chris Metcalf, Mellanox Technologies http://www.mellanox.com