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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5B42ECAAD5 for ; Fri, 2 Sep 2022 16:07:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5F7EF8D0029; Fri, 2 Sep 2022 12:07:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5A7458D0014; Fri, 2 Sep 2022 12:07:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 496538D0029; Fri, 2 Sep 2022 12:07:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3BB168D0014 for ; Fri, 2 Sep 2022 12:07:04 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 08C021C6830 for ; Fri, 2 Sep 2022 16:07:04 +0000 (UTC) X-FDA: 79867624368.12.0721E5D Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf31.hostedemail.com (Postfix) with ESMTP id A69E42006E for ; Fri, 2 Sep 2022 16:07:03 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 097FCB82C7D; Fri, 2 Sep 2022 16:07:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32BD1C433D7; Fri, 2 Sep 2022 16:07:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1662134820; bh=NrdRZZGQpIkJd2dPFQ5BPqaAgpxFgSkcxmdBBCfc9fQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=N0Uiy4R2LFCrLawuMjtPukyIXv+tBTvCJvdfG+wYzM0hZxvrHdUmBfI4yOrfMDgi9 5ssO9knq2+oAImjDMH7M4iMr4S1sqtHoZNeCA29JbDOrtLjNVw3A+719ZNIlSW60bp E8PSCrR/rUXdeufPP6hjY0nmEE6wAK7g6nn816LA= Date: Fri, 2 Sep 2022 09:06:59 -0700 From: Andrew Morton To: Jiebin Sun Cc: vasily.averin@linux.dev, shakeelb@google.com, dennis@kernel.org, tj@kernel.org, cl@linux.com, ebiederm@xmission.com, legion@kernel.org, manfred@colorfullife.com, alexander.mikhalitsyn@virtuozzo.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, tim.c.chen@intel.com, feng.tang@intel.com, ying.huang@intel.com, tianyou.li@intel.com, wangyang.guo@intel.com Subject: Re: [PATCH] ipc/msg.c: mitigate the lock contention with percpu counter Message-Id: <20220902090659.28829853543cac3f3f725df5@linux-foundation.org> In-Reply-To: <20220902152243.479592-1-jiebin.sun@intel.com> References: <20220902152243.479592-1-jiebin.sun@intel.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662134823; a=rsa-sha256; cv=none; b=iyTOYBLruUkLoP3REzWFvJbvDUvJdmaNNg6kaQX+7Q5BzRwmW6/JQaU3Y7iPJIXrihg78H m1Ekbf0rA+mVh9q+02aAAovmB1I103G7ePM5AeO8uzEeW0QPcc+5KJkxAKtZI+1JePvytq 3DvLzfl/2obOHtzawz26SV8GWgleQaA= ARC-Authentication-Results: i=1; imf31.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=N0Uiy4R2; spf=pass (imf31.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662134823; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8S32CO6LTROSOwgbcipFVYR66fqOongDUpmU8ssTStA=; b=oZdNjfOwf8fYCA+xsV8Dw7ZsCsybJJe/lsEoQ57doVy4DeCaUoSlwoiOyzxwhs1Mg5RRBq 8ZgDAWmOXTWuiRQES8MGxCnxDa/sNhqNZneA3w0b2ZGgYsMRb4GrWpGdcbpZ1AcisMpAha ZOv6Gin54ejgmf1aYuxlr/t3ZXf8UPY= Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=N0Uiy4R2; spf=pass (imf31.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Stat-Signature: zqmbe6k6h9sx3i959z7k1hbgjb5jstyn X-Rspamd-Queue-Id: A69E42006E X-Rspamd-Server: rspam04 X-Rspam-User: X-HE-Tag: 1662134823-681923 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 2 Sep 2022 23:22:43 +0800 Jiebin Sun wrote: > The msg_bytes and msg_hdrs atomic counters are frequently > updated when IPC msg queue is in heavy use, causing heavy > cache bounce and overhead. Change them to percpu_counters > greatly improve the performance. Since there is one unique > ipc namespace, additional memory cost is minimal. Reading > of the count done in msgctl call, which is infrequent. So > the need to sum up the counts in each CPU is infrequent. > > Apply the patch and test the pts/stress-ng-1.4.0 > -- system v message passing (160 threads). > > Score gain: 3.38x So this test became 3x faster? > CPU: ICX 8380 x 2 sockets > Core number: 40 x 2 physical cores > Benchmark: pts/stress-ng-1.4.0 > -- system v message passing (160 threads) > > ... > > @@ -138,6 +139,14 @@ percpu_counter_add(struct percpu_counter *fbc, s64 amount) > preempt_enable(); > } > > +static inline void > +percpu_counter_add_local(struct percpu_counter *fbc, s64 amount) > +{ > + preempt_disable(); > + fbc->count += amount; > + preempt_enable(); > +} What's this and why is it added? It would be best to propose this as a separate preparatory patch. Fully changelogged and perhaps even with a code comment explaining why and when it should be used. Thanks.