From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: ** X-Spam-Status: No, score=2.4 required=3.0 tests=CHARSET_FARAWAY_HEADER, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F351C433DF for ; Thu, 21 May 2020 04:19:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF3F320748 for ; Thu, 21 May 2020 04:19:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=tencent.com header.i=@tencent.com header.b="T1r/i0Pz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726882AbgEUETG (ORCPT ); Thu, 21 May 2020 00:19:06 -0400 Received: from mail4.tencent.com ([183.57.53.109]:34018 "EHLO mail4.tencent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726282AbgEUETG (ORCPT ); Thu, 21 May 2020 00:19:06 -0400 X-Greylist: delayed 550 seconds by postgrey-1.27 at vger.kernel.org; Thu, 21 May 2020 00:19:03 EDT Received: from EX-SZ018.tencent.com (unknown [10.28.6.39]) by mail4.tencent.com (Postfix) with ESMTP id 62AC3722D9; Thu, 21 May 2020 12:09:51 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tencent.com; s=s202002; t=1590034191; bh=0J/Iyor6JI7kRj1E77ZmS5fAyQEZe9jJ3ekKIr2jbXE=; h=From:To:CC:Subject:Date:References:In-Reply-To; b=T1r/i0PzgUJ5D5/W/TEnUAd9CFz+RI7PKOjiIvW7trPFyeqjvCrianLh5Z2edQOM9 26iOF8GPEygYRhvMtQC1wYkZElc7rtI0oajiMu0uGpyUeuYEYyCuCyVNEXbkpiWMYc bdOFn6Bfiv4GKY//cF6GL3oCWSIrwUGUwUEmldzs= Received: from EX-SZ006.tencent.com (10.28.6.30) by EX-SZ018.tencent.com (10.28.6.39) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Thu, 21 May 2020 12:09:51 +0800 Received: from EX-SZ012.tencent.com (10.28.6.36) by EX-SZ006.tencent.com (10.28.6.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Thu, 21 May 2020 12:09:51 +0800 Received: from EX-SZ012.tencent.com ([fe80::704d:4b2e:562c:22c]) by EX-SZ012.tencent.com ([fe80::704d:4b2e:562c:22c%3]) with mapi id 15.01.1847.007; Thu, 21 May 2020 12:09:51 +0800 From: =?iso-2022-jp?B?YmVuYmppYW5nKBskQj5VSTcbKEIp?= To: "Joel Fernandes (Google)" CC: Nishanth Aravamudan , Julien Desfossez , Peter Zijlstra , "Tim Chen" , "mingo@kernel.org" , "tglx@linutronix.de" , "pjt@google.com" , "torvalds@linux-foundation.org" , vpillai , "linux-kernel@vger.kernel.org" , "fweisbec@gmail.com" , "keescook@chromium.org" , "kerrnel@google.com" , Phil Auld , Aaron Lu , Aubrey Li , "aubrey.li@linux.intel.com" , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini , Joel Fernandes Subject: Re: [PATCH RFC] sched: Add a per-thread core scheduling interface(Internet mail) Thread-Topic: [PATCH RFC] sched: Add a per-thread core scheduling interface(Internet mail) Thread-Index: AQHWLvXKFOwpUhEtgUmeB0cRYW4c1KixZ1AA Date: Thu, 21 May 2020 04:09:50 +0000 Message-ID: <71B72E96-CD6E-43C3-B22B-ADE0EC78C550@tencent.com> References: <20200520222642.70679-1-joel@joelfernandes.org> In-Reply-To: <20200520222642.70679-1-joel@joelfernandes.org> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.28.2.16] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On May 21, 2020, at 6:26 AM, Joel Fernandes (Google) wrote: >=20 > Add a per-thread core scheduling interface which allows a thread to tag > itself and enable core scheduling. Based on discussion at OSPM with > maintainers, we propose a prctl(2) interface accepting values of 0 or 1. > 1 - enable core scheduling for the task. > 0 - disable core scheduling for the task. >=20 > Special cases: > (1) > The core-scheduling patchset contains a CGroup interface as well. In > order for us to respect users of that interface, we avoid overriding the > tag if a task was CGroup-tagged because the task becomes inconsistent > with the CGroup tag. Instead return -EBUSY. >=20 > (2) > If a task is prctl-tagged, allow the CGroup interface to override > the task's tag. >=20 > ChromeOS will use core-scheduling to securely enable hyperthreading. > This cuts down the keypress latency in Google docs from 150ms to 50ms > while improving the camera streaming frame rate by ~3%. Hi, Are the performance improvements compared to the hyperthreading disabled sc= enario or not? Could you help to explain how the keypress latency improvement comes with c= ore-scheduling? Thanks a lot. Regards, Jiang