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Wed, 23 Jun 2021 10:41:53 +0000 Date: Wed, 23 Jun 2021 18:41:42 +0800 From: Jisheng Zhang To: Thomas Gleixner Cc: John Stultz , Stephen Boyd , linux-kernel@vger.kernel.org Subject: Re: [PATCH] timer: Use static_branch_likely() for timers_nohz_active Message-ID: <20210623184142.255b2769@xhacker.debian> In-Reply-To: <87o8bydj0n.ffs@nanos.tec.linutronix.de> References: <20210513143354.096c6baf@xhacker.debian> <87o8bydj0n.ffs@nanos.tec.linutronix.de> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Originating-IP: [192.147.44.204] X-ClientProxiedBy: BYAPR01CA0071.prod.exchangelabs.com (2603:10b6:a03:94::48) To BN9PR03MB6058.namprd03.prod.outlook.com (2603:10b6:408:137::15) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from xhacker.debian (192.147.44.204) by BYAPR01CA0071.prod.exchangelabs.com (2603:10b6:a03:94::48) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4264.19 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?awr6dkpoavFIQXXmP+F6jeAk28h7h5wr3bZh8MFqQkV72cctpVxDC3MrU/ES?= =?us-ascii?Q?c1//0cfNNH+pLlsEj6nP1NxazS1F+a6GChjPHeLAfuL6943lsTH7bffs3R/s?= =?us-ascii?Q?h2FfUz64/mngc4+owMEh22vWtNwZfc2weuaNGy1Pw8U0mkG388jW/Hmj2qd5?= =?us-ascii?Q?GyCBNWigUsACcIbFShYZAsqyWol0FvL3/bWBhMb4YDOGY7kjiKAi9bLz8Hmg?= =?us-ascii?Q?v9Ci0cjHcmQLhiIX4xqnfmhVH4/ceIhRbz4yhpVl6Y1j/wFFPVraqYMGjo3A?= =?us-ascii?Q?JHEncG4duHhykcii89iZDPIdkSGEtljlC+ORxVAs6QIVHbUZ69QTQsLRxy+u?= =?us-ascii?Q?WKRLCy4UxJypxHWM2v994OM/fYULybyIzvU21RbSPEYHdlW00k6qWPGRptTn?= =?us-ascii?Q?N9scd8mc2+Zz7ybJJk/7Ch6NGT7TfPq5xW3TDGdfSF25b3LZVKxfFeNEiGFj?= =?us-ascii?Q?GeowUXa0SY/iuSKPDPO9KU1nXN3+oQBPXEPSd1AlNASTZLhC6PPqHn927pVF?= =?us-ascii?Q?wik4CmEhK0MxZFov3k+MqUX1yjJkoNjM0INl5DE6lONUwq9EsPqzrWdZfcrj?= =?us-ascii?Q?VlKdBwdYG9zeLJ5t4XgTzGacvsmzlb9WD2iE6KZVJsNH05DGl6ybaV74s5Ri?= =?us-ascii?Q?jwhIFsO39WDaJiXtAdGLhMuAzgXSviWVxT129R5WIXX6yFBwViNkAbQOyW8C?= =?us-ascii?Q?BPJDhEx0v16HLl7gBgjvZNuLHLcGFDam1RrObAfAUoXhTl28xAkz96xemgt8?= =?us-ascii?Q?AjDZXLk9cqI+fYImN3IiMpJedMq8H6bnljIUlfmH9ZXSJ1Z5u0c+45knMs+R?= =?us-ascii?Q?R7bXm5g+SiTU6HEFhU+Fq5bEeC35ybI7523d7DN3JIimUT4rMzlgnXzhKPfG?= =?us-ascii?Q?GB+5EXPMuzrbuR3xBYnsLcvUN/cj5zqKPEsOfwwKaWPJIgeJfmxIA0F4DWJZ?= =?us-ascii?Q?KuPS2SSwkmHsDIx/8bqRp+o1p8KOnR/3EK2iVsX8UvOAJFzNBHTbt8UjK4XG?= =?us-ascii?Q?iSURnmN8iz7Zs7v7lOEiSv5IX7xWnm02ZqwwpgHAyuYcaM1ppZ7Oto73uSR8?= =?us-ascii?Q?fQjVC8Wza7Az2CcSYxeQLFF+StAwH1RJ3s7N2HLRqrtEQg2JdAD9NSxnJMol?= =?us-ascii?Q?k3HXKLlpkahtSy84RURDEsb2NAO1p9JQTqNVAAlj7RgjPSbuDPH+C/MCV3su?= =?us-ascii?Q?nXpsz++bvJeQWpkPT8zFSVsVlAE82+5Vh3vRDSJh1KEq6XwKonOZwSRqmtZS?= =?us-ascii?Q?hV7eQXNo5W8dBac3fscAevVvCWThL1PAC3iVc3ysZ3bYunzSgCvPC7IonHJY?= =?us-ascii?Q?HA6k0wJiQW1Z56AFfhApf5r+?= X-OriginatorOrg: synaptics.com X-MS-Exchange-CrossTenant-Network-Message-Id: cd9156d2-bffd-48b8-2af0-08d9363383db X-MS-Exchange-CrossTenant-AuthSource: BN9PR03MB6058.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Jun 2021 10:41:53.5077 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335d1fbc-2124-4173-9863-17e7051a2a0e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: i1XGaxxX0DoK/bWUOUB5k+bkBSUS+gpTFON8Qy1d//BDGSAtmUHL9k/K0j3tt3Nk/TiQND5NNOLcJM0MsYdQBA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN6PR03MB2610 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 22 Jun 2021 17:19:20 +0200 Thomas Gleixner wrote: > > > On Thu, May 13 2021 at 14:33, Jisheng Zhang wrote: > > NOHZ is likely to be enabled, so use static_branch_likely() to > > Why is it likely to be enabled? Did you make a survey of the wider > distro universe or what? One more thought: maybe NOHZ is confusing, what I mean here is: timers_nohz_active is likely to be true. If I update the commit msg as the following, is it acceptable? "timers_nohz_active is likely to be true, so use static_branch_likely() to reflect this fact. This could improve the finally generated code a bit for the most likely scenario, I.E save two "jmp" instructions." Thanks > > > reflect this fact. This could improve the finally generated code > > could improve? Either it does or it does not. > > Thanks, > > tglx