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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37772C433EF for ; Thu, 24 Feb 2022 13:44:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234720AbiBXNpD (ORCPT ); Thu, 24 Feb 2022 08:45:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233007AbiBXNo6 (ORCPT ); Thu, 24 Feb 2022 08:44:58 -0500 Received: from p3plsmtpa06-08.prod.phx3.secureserver.net (p3plsmtpa06-08.prod.phx3.secureserver.net [173.201.192.109]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2229426F4E6 for ; Thu, 24 Feb 2022 05:44:29 -0800 (PST) Received: from localhost ([82.17.115.212]) by :SMTPAUTH: with ESMTPA id NEPynxQ5Itbo2NEQ0n87OC; Thu, 24 Feb 2022 06:44:28 -0700 X-CMAE-Analysis: v=2.4 cv=M8iIlw8s c=1 sm=1 tr=0 ts=62178bbc a=9gipVNR6X1CoIeAWHwLoWw==:117 a=9gipVNR6X1CoIeAWHwLoWw==:17 a=IkcTkHD0fZMA:10 a=dryZNVXSxjYntoBgU78A:9 a=QEXdDO2ut3YA:10 X-SECURESERVER-ACCT: atomlin@atomlin.com Date: Thu, 24 Feb 2022 13:44:26 +0000 From: Aaron Tomlin To: Marcelo Tosatti Cc: Aaron Tomlin , Frederic Weisbecker , Christoph Lameter , tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Phil Auld Subject: Re: [RFC PATCH] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too Message-ID: <20220224134426.ai7demvrupzy6lu5@ava.usersys.com> References: <20220217124729.GA743618@lothringen> <20220217142615.xqtiydixvnumyvei@ava.usersys.com> <20220217163205.GA748087@lothringen> <20220218125454.utlgmuhijklzr3if@ava.usersys.com> <20220219154616.pwsvh445x3vn7ltf@ava.usersys.com> <20220224130014.rmhtx3xlepybuxn2@ava.usersys.com> <20220224132816.qsfa66ao3xdjdxxx@ava.usersys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-CMAE-Envelope: MS4xfCEzHm3PJhNGG/t1WGRX1uIq4CTw1/ohvmRt+lOAbOWx+NaU1T9Xe8vUdDEkhfCci4DYz4STHFa4a2B5oVghjtutom7a5mLDK8h/zj7y+umS91dotgLF dWgst43fXC+M5LGpz7TSb30O2DWLp3SdPtJrgQuGQxBLU6QNZ0iIy+BYbkm3UlBfKE0Ha/TPw1nVs6793xclOU5/eMdudGsOLaFLnHsJIH/DUs/h9clvJusQ LJdITso7ZAFguPkXroY7Etr7XVmk6FjBicAoU6k4ekfVVuWYosFzpSfJdYSWY8CNHnqmUEZwuNsp6pIYIivlZxKqSb60kdYRnpOM3JvhIVt3Q5g4EbobKal9 iM9cqm2xnuvsyPQu62yLYuHv5cgHApSPqtfnUzS4qE+fg7WTLP06acJg9q6wqgYYL+OrTsQw Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 2022-02-24 10:40 -0300, Marcelo Tosatti wrote: > On Thu, Feb 24, 2022 at 01:28:16PM +0000, Aaron Tomlin wrote: > > On Thu 2022-02-24 10:14 -0300, Marcelo Tosatti wrote: > > > If the per-CPU vmstat_update is limited to happen once per second, that > > > shouldnt be a significant performance impact? > > > > Perhaps not. Albeit, is the interrupt worth it? > > Its a requirement for correctness right? Yes, this is true. > > Then again it could indeed > > be a long time before the idle task is selected and a return to idle code > > were we'd check for any remaining differentials with the aforementioned > > patch. > > Or a long time before userspace returns to kernel. Indeed. I'll put together a patch for comment. Kind regards, -- Aaron Tomlin