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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 D70E1C47084 for ; Tue, 25 May 2021 07:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B672761284 for ; Tue, 25 May 2021 07:14:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231493AbhEYHQP (ORCPT ); Tue, 25 May 2021 03:16:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229503AbhEYHQO (ORCPT ); Tue, 25 May 2021 03:16:14 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C00AC061574; Tue, 25 May 2021 00:14:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=uehh4cPPcsHkI+ofqFVA/9YB9cJWcIz/8uLMkzzVSu8=; b=XzNIiRP+DH+CDt+hgDALUsVNng lHK9X1wzN+4A/ZOIjAsp2FGB+pmCBn3/LS6bhLf+LJ/GHAcV4yf0BW0gox+4yPYa8eHdlHosrBbxl MASrTUt/7ygG5O/iH1++y+9o1GEBq7HSvHX0XpTIa91x3pZjopHo594ge099Q2ILpJChZ+67byR8E pdH3PO7Bx4vvjzdKWQaGS3SIKYPbzKCo+qQanGNUKKFg6Jj6EU8pLuuRkT9bs6dGKmsYYHZYgSwaU ueNQv0b24QFK0oiZTISUCNUY6EjEnz8Dn5pavsn5a5QMCbzi4WMkkRnvA06cJq2SSbTyrdx11evrU KnmL+Q9w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1llRFN-003DpG-DE; Tue, 25 May 2021 07:13:04 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 96F153001E4; Tue, 25 May 2021 09:12:59 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 76B0131474564; Tue, 25 May 2021 09:12:59 +0200 (CEST) Date: Tue, 25 May 2021 09:12:59 +0200 From: Peter Zijlstra To: Suren Baghdasaryan Cc: tj@kernel.org, hannes@cmpxchg.org, lizefan.x@bytedance.com, mingo@redhat.com, shakeelb@google.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, minchan@kernel.org, corbet@lwn.net, bristot@redhat.com, paulmck@kernel.org, rdunlap@infradead.org, akpm@linux-foundation.org, tglx@linutronix.de, macro@orcam.me.uk, viresh.kumar@linaro.org, mike.kravetz@oracle.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v3 1/1] cgroup: make per-cgroup pressure stall tracking configurable Message-ID: References: <20210524195339.1233449-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210524195339.1233449-1-surenb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 24, 2021 at 12:53:39PM -0700, Suren Baghdasaryan wrote: > PSI accounts stalls for each cgroup separately and aggregates it at each > level of the hierarchy. This causes additional overhead with psi_avgs_work > being called for each cgroup in the hierarchy. psi_avgs_work has been > highly optimized, however on systems with large number of cgroups the > overhead becomes noticeable. > Systems which use PSI only at the system level could avoid this overhead > if PSI can be configured to skip per-cgroup stall accounting. > Add "cgroup_disable=pressure" kernel command-line option to allow > requesting system-wide only pressure stall accounting. When set, it > keeps system-wide accounting under /proc/pressure/ but skips accounting > for individual cgroups and does not expose PSI nodes in cgroup hierarchy. > > Signed-off-by: Suren Baghdasaryan > kernel/sched/psi.c | 30 +++++++----- Acked-by: Peter Zijlstra (Intel)