From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941607AbcIZVYr (ORCPT ); Mon, 26 Sep 2016 17:24:47 -0400 Received: from mail-bn3nam01on0116.outbound.protection.outlook.com ([104.47.33.116]:22429 "EHLO NAM01-BN3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933263AbcIZVYp (ORCPT ); Mon, 26 Sep 2016 17:24:45 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=waiman.long@hpe.com; Message-ID: <57E99214.3040104@hpe.com> Date: Mon, 26 Sep 2016 17:24:36 -0400 From: Waiman Long User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: Stas Sergeev CC: Andrew Morton , Ingo Molnar , Oleg Nesterov , Thomas Gleixner , , Scott J Norton , Douglas Hatch Subject: Re: [PATCH v2] signals: Avoid unnecessary taking of sighand->siglock References: <1474649774-48834-1-git-send-email-Waiman.Long@hpe.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [71.168.64.185] X-ClientProxiedBy: BY2PR1001CA0014.namprd10.prod.outlook.com (10.164.163.152) To CS1PR84MB0312.NAMPRD84.PROD.OUTLOOK.COM (10.162.190.30) X-MS-Office365-Filtering-Correlation-Id: 1f97b640-8c6d-46ae-fbe3-08d3e6538856 X-Microsoft-Exchange-Diagnostics: 1;CS1PR84MB0312;2:IVIIc5iXZrhqIEA/IMrCAHKrjDbDHUHQ/hOYbc3gxKZLT1fKmplXgTVdtNSJj7OnmicFxvo+Bvf3xovVFvKoSrFyxIQXTGxMePY974vTkNreyY5pbtIBsjO5CPqriNEour3JFGu2L+uCc+gTjgDey1ZPwNoTzqURXhlcXYKqdlgFfMQMnjBdbw/kLcDFpVm9;3:ufYlSvc4VQqPtSru50WHKgdFUlkkEW47nK4mCyPLU6AOFVXJmuz8eIrsQFLIvwVujgtJ10RMrR0IDKltq3UVJBT2QK9o+TtaigyuPrRQGt9zglktsn4CqS8qSuvXcpng X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0312; X-Microsoft-Exchange-Diagnostics: 1;CS1PR84MB0312;25: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 X-Microsoft-Exchange-Diagnostics: 1;CS1PR84MB0312;31:oe9avgJeYNIGcgdwmbwzfXjirpXujKc9HHdAtNIt612utk/8pg6ffLquxj6/feBT7wMFKzVIDvonQbDrG7IStdxyofzelwNrd05jbwiRdH1ibkBFP3aLIfutVM5EmAPRBfvTlwMF02jMPMsPOqBQspi4ZgKD6ZGmT4ufz+J3tPzY3Ju3ezyMbwqSm0I0W5Cw2UPjfG4/NVpIt2r3Iw+Az1KpC4fl+UnBVxRKbLvV/KU=;20: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 X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(6040176)(601004)(2401047)(8121501046)(5005006)(3002001)(10201501046)(6055026);SRVR:CS1PR84MB0312;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0312; X-Microsoft-Exchange-Diagnostics: 1;CS1PR84MB0312;4:jGg2U+Zqw5EfZwX9kTsTrkaCp1VRh+AzVdirFagUSlBqHWYxKu7R0ZmYmML5Yd4Yu56dpHUl81qNc4Zctg2T/EdnYH9jeOFE4g4ueJ7f9isfSR42RiO5hiDX8aJbdclZ9cjWyBvFllStIxrHVSgKGIdjFj8vc0gDsEdSAkeFzw1DMvDN4yh3aLGWzwV4eGDzequzDQRLLhffx2mr0c0zyEFxFndVxXUI23wuVLKhEV8rVmkGuWTV15S7L/pMrwGSYfsHSJR8qDPwP+SDCFHnbtlCTzb47PZlsvTz+OqjNA2R0hoUhUuVqLh2iAyMWKIbEQOSKiwtybVj0Z9TTY9KDlMTmpXVp10r7Y3LJHVaj5fwvNVGdfqOSr9LganX0MmkWKaTsOsyqPYTS/+3mlhi4w== X-Forefront-PRVS: 00770C4423 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10019020)(4630300001)(6049001)(6009001)(7916002)(189002)(377454003)(24454002)(199003)(110136003)(59896002)(105586002)(80316001)(8676002)(81166006)(81156014)(117156001)(64126003)(97736004)(4001350100001)(86362001)(2906002)(42186005)(4326007)(65816999)(101416001)(66066001)(2950100002)(65956001)(77096005)(65806001)(47776003)(6916009)(189998001)(7846002)(6116002)(50986999)(3846002)(7736002)(106356001)(5660300001)(586003)(87266999)(76176999)(54356999)(305945005)(50466002)(33656002)(83506001)(2870700001)(92566002)(36756003)(23676002)(68736007);DIR:OUT;SFP:1102;SCL:1;SRVR:CS1PR84MB0312;H:[192.168.142.133];FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; X-Microsoft-Exchange-Diagnostics: =?utf-8?B?MTtDUzFQUjg0TUIwMzEyOzIzOnI3a0lacGRkL1VJckl2eUJxVHQvQy9KU1Yz?= =?utf-8?B?VTJERGlJRjBBclpreXR0cy9IcUZTL2VkT1NjYjhYcFVXOVBYczRUd3NpaDUw?= =?utf-8?B?Rmw5TDdhMnA4QmdQMzRnc2R6UWNCSVgwSGc2b2pYRXNPQ1A4MzVkbmp0a0Vw?= =?utf-8?B?VVRxSmNYTmNlUUZJb2pDWnJ1QkNvemlmazVmbk5uT1ord0tOeWZKQjVWamVJ?= =?utf-8?B?eFgvUmkxQlhDODBoTFkyYVBhbDZiVmpTblZKZTFmM2xGWCtkTUlYanFkQThP?= =?utf-8?B?dTNUNkJkU0c0QkwzR2NTMkZNNEs3dnhFZ3V0R1NDWjR5WU9USlgzRUp3Y0Ry?= =?utf-8?B?SElIM0dVOGg4ZENaRFh5WEZnS3hpNnZmYm9KMGNZSzRTcFFIM0ZXMnhLSGFQ?= =?utf-8?B?SUlFWVBMaWJ6WFZFcjV3UTFTOFZzNzR4cWNKeHBoRXNtQlJoWndRZ3djR3k1?= =?utf-8?B?YjdhK21CdG1LNEVRQllmU2x5NXVSN0tJQUhsbHl1SnlVVnBnQk4wUnVacm0x?= =?utf-8?B?anBhYmNkcTEwR0dKeWFRRmVuVEwrcks3NVJqMlBCZFQ2bmRyQ28xMi9aNlpk?= =?utf-8?B?VkdNTHo3OE5LenpQUlRoR0JEelFYTVdkbWtkbmZid3BGaFNUNmw1dUZzelJk?= =?utf-8?B?N1NJM3F2SytqVjRrVDhCaFdsRVFOM3pZWTdoM2FPQ3EwWVFqSzVjS25kMDJ4?= =?utf-8?B?VWFxWFh1M1VkQnBTTm8rNkxUUTZLWnNEeXBseFNHd24wQktiUUlTSi9KdGxt?= =?utf-8?B?clRBMFBrZG9RZUJhbllEWWhYTFpsdjFrUktIQmlkUGpjRis3VXBQMExOM3RJ?= =?utf-8?B?WVhRNEVFZ3l4TUhHZW9wRjlxMlZTaVVTZGNGM1F1Nit2cm1iOHZTR3pDRnp3?= =?utf-8?B?QnRoUVJnMU83MkkvMVhpZXdUK0pNaCtFbFJvZUd4WnNXTG1BMm96OXFidVBh?= =?utf-8?B?b05rM3h0UjIrS2ZweEExUlY2aERqU3hNOGJ5eDc0WlZtM0s2VUhsU1hjUnlM?= =?utf-8?B?Z0xHQkJ2Q3g5VWRmeXIrM1YvQjBya3hVaVptcFM5T0k2RGNCdDU5WU80ZWZZ?= =?utf-8?B?ZGdMREV2RVJXMU9lRGtOT3JrRFNibCtuK1ljNG55emdvOXZYK083Ykd1UEVB?= =?utf-8?B?Q0IrVDdwZHJWdGlzblk5em5ZazNRMm1sSG5jV0JRWmFmOVZrUUZjQnY0YjVZ?= =?utf-8?B?eXN5dXArYzZNaUsxZFU3TklQMHllaVd4SXZSeHI4NlpxcWJYakRBajZ2bHJH?= =?utf-8?B?TFFFMGR3STd4Mk1OVy9JcWs0TXJWQzV6ZmFGODVoaFdNc3lWTjNUYmV4ZmVk?= =?utf-8?B?cXlJYnhmNU5KeUg1N3BtNDAxME9iRHB6L3dSQ05Md3pFTHBPN0RzOWtpVzlM?= =?utf-8?B?U1QvOXdBZkZxZjJEVW43eGxuNm9LdEg3ZUxwT3E1eUlJMVlWYjBuUU0rSllk?= =?utf-8?B?dHdxeGpCdTVjTFl4aGVEcEhxZnFZdUpGMHgwVElqSmh6V1NyR1dQMSswOFl1?= =?utf-8?B?SzZ5aDRSQlRTdmdVVnVDbjF6UGYwWW44OWVyWU5XMVpMU0RvWDg4cGNwVndi?= =?utf-8?B?MnlIM0VjZmExUkFFQjhsQVZpbkp3dW5ycWh0bSs0T3NXdVNCUm9FejFFOWFu?= =?utf-8?B?VWJpM0ZJODB3YjF1dXhRMEZKenFtSnlhSmJuS0tudk8zS2pSc3AyeC9EQkhG?= =?utf-8?B?ajc5UnFhejFZODJoSVRJRnA0bjBoY3p0L09xRFlrRURRRDN3YmViTmRjbGly?= =?utf-8?Q?hoE1a6s6I6NcBIR4ioLhsCF154yVTELWQialk=3D?= X-Microsoft-Exchange-Diagnostics: 1;CS1PR84MB0312;6:Nf1WSz9sR3Pc0zH8jDCqyWdTP0a1Mt4yKaOKWCLcAYoNjvPxtBT5Jalcw/qbn5i71DnG5HzOiYTT3EQkj5v5vEgWrtFMxlmUXmtkTg+J/8dkIObojcfVP+Ts+/3ljIjZEEoXmNjqBhSGTPy/JHjoWXHsc7EBbvICsOwYAduUhishGMWECSrbmn41NIoZpWhESgsyeWJGj+pZEZkv52hs1MAG2uGXJnnIs8cw3Z6VL1XHgNOg3AngXhvkml0mVvxGnFYcaPiRnSIvfEyiJg1wE9kwDi//2XUH/cCp50+FXsLfVzGRIo90VdzPKPidaOlHzTfPwRF+kt4BKuJoYho86w==;5:hrUqqV2GfqdMK2busDdDU2RqvgBkK2jNniPttmaYNH3M3w/OL/JleNs1RFbQFsRWPXrDyaZmyKtGWQ4+Sl3o/DpPzWtg7esjbVYaGSyAXeuYBHx1Ney0vJhAd6I0utbmQABw2XpDMyCOYIVrplfvow==;24:Sc9TJZRzc2oNU9LszZ/ZJ+Hf1ryZfKxeeUjBm9UOUbmjtKwiH/SoGNftd1P8AxSkoD5XwdKr1z839ttm6oB7j9o4u9Q9LxqONRifq44F0O0=;7:gpexdLQgjYcF8bUcsTQ7HWtdN+AJ57YtC/vqH+ch3/ORpyYceJNCY55Cfs+o6yV42uAeiRtSUs4eBpAXMfpVy2pf8Rbu9OEkD9swKsZaoaiCLGVwklKYapcQYHKturv8pXf03ObK/pCS67iDo6AsQjaypdqbbJopGt7cvfMpfq79tps4svntoRg9Qbv9nsYk09WPiEntEyGYYEmDnsj6PF03z9aa3cR+rMVJaGPY98SZPZ97gnYqqzdW1FlTXGeDSCS7pM0kbJWQzSCFzKlcnJumug/YEkJ9Tv6bTJ5CrmssgE9lHj19nwQ0X9jwiXcE SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: hpe.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Sep 2016 21:24:41.9326 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: CS1PR84MB0312 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/23/2016 03:43 PM, Stas Sergeev wrote: > 23.09.2016 19:56, Waiman Long пишет: >> When running certain database workload on a high-end system with many >> CPUs, it was found that spinlock contention in the sigprocmask syscalls >> became a significant portion of the overall CPU cycles as shown below. > Hi, I was recently facing the same problem, and my solution > was to extract swapcontext() from libtask - it has better semantic > and does not do sigprocmask. How much you hack sigprocmask, > it is still faster to just not call it at all. > Alternatively, perhaps the speed-up can be achieved if the > current mask is exported to glibc via vdso. > Just my 2 cents. The problem was in a third-party software not under our control. I am just doing my part to try to alleviate the problem from the kernel's perspective. Cheers, Longman