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 E4406C54EE9 for ; Wed, 7 Sep 2022 16:02:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0F2916B0072; Wed, 7 Sep 2022 12:02:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A1366B0073; Wed, 7 Sep 2022 12:02:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EAAF08D0001; Wed, 7 Sep 2022 12:02:28 -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 D7DE76B0072 for ; Wed, 7 Sep 2022 12:02:28 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id AC072C19EF for ; Wed, 7 Sep 2022 16:02:28 +0000 (UTC) X-FDA: 79885756776.21.BEEAB61 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf07.hostedemail.com (Postfix) with ESMTP id 909EA40067 for ; Wed, 7 Sep 2022 16:02:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662566547; x=1694102547; h=message-id:subject:from:to:cc:date:in-reply-to: references:mime-version:content-transfer-encoding; bh=8qmgsTp0R++7umL+kTPdAI4AENu4bF7ohljPEUK86+0=; b=S3B0MGN0jiZYkJ5BMtQB/Jdy5lmqcO56RvBvJlmXmM8RJaqWVBlWaMXM Yg7HGOEyWVqvs/+perj2YY7VoXPE7OBJKLsXbniZ8s646O6xr4bIJEOjJ NBTSb25MAgH2vMJqvfWb3Qgtb91FnZjM8fCXS9+WOuQBi3Vz9PXHYLaJ2 zeK7frJZlrhxKtz42saQZErkihaefk5cqIV76b1tXGi0zF/02aqcCS3hA UqxNjWhOm6U9BkUVVlKXSu730ENoCFfNZfTfbrgH+s5V9jd+jZXLcG8FZ nDIPiCjT98tALD8maiXY8rckTkdfpVkUXDnXB5I/YUxGXRhV5iY12HYlR Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10463"; a="383211852" X-IronPort-AV: E=Sophos;i="5.93,297,1654585200"; d="scan'208";a="383211852" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2022 09:01:54 -0700 X-IronPort-AV: E=Sophos;i="5.93,297,1654585200"; d="scan'208";a="565570756" Received: from schen9-mobl.amr.corp.intel.com ([10.209.53.232]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2022 09:01:53 -0700 Message-ID: Subject: Re: [PATCH v4] ipc/msg: mitigate the lock contention with percpu counter From: Tim Chen To: Jiebin Sun , akpm@linux-foundation.org, 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 Cc: tim.c.chen@intel.com, feng.tang@intel.com, ying.huang@intel.com, tianyou.li@intel.com, wangyang.guo@intel.com Date: Wed, 07 Sep 2022 09:01:53 -0700 In-Reply-To: <20220907172516.1210842-1-jiebin.sun@intel.com> References: <20220907172516.1210842-1-jiebin.sun@intel.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 (3.34.4-1.fc31) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=S3B0MGN0; spf=none (imf07.hostedemail.com: domain of tim.c.chen@linux.intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=tim.c.chen@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662566548; a=rsa-sha256; cv=none; b=34MSNtC5RR2wWvsdRAvqahGGQ0mKwNqk3sO1KYa3qhG3rXQ3O/02ntSmdMG5esP6VrF+jJ jkTjBLpDSyPJk1TByd6H4X55uUU1Y/THOOEpjqECSHGFb1S3z2XqJuFEFc2QCru6x9znzA 3hkIF+GAuLMR1aGMBuyew5S8ygu/FSw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662566548; 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=35GR41yR8jWXOhFEzIXlyIjwMF0V+CGKRaL/y+v6PxY=; b=vUb0DGpCuJgc2LAQQbNvs1a+B3S2JFmjtx+9fsGVjLs/m4VZ12dklGvHO+Vlv6jOShSmhP ZuxgtZuOqRdcTGl39XrNKONlF9Q3NDP8ODBhWyUACtE+A0MC6D8luVu+aSXTA4IGiW/A9S Q8NviyMBSjsTkcezQz+RkFKIYyX4CJc= X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 909EA40067 Authentication-Results: imf07.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=S3B0MGN0; spf=none (imf07.hostedemail.com: domain of tim.c.chen@linux.intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=tim.c.chen@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Rspam-User: X-Stat-Signature: rxfcfswb1djgiyifq16o4fdweqc96jmx X-HE-Tag: 1662566547-60242 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 Thu, 2022-09-08 at 01:25 +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_counter > greatly improve the performance. Since there is one percpu > struct per 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: 3.17x > > ... > > +/* large batch size could reduce the times to sum up percpu counter */ > +#define MSG_PERCPU_COUNTER_BATCH 1024 > + Jiebin, 1024 is a small size (1/4 page). The local per cpu counter could overflow to the gloabal count quickly if it is limited to this size, since our count tracks msg size. I'll suggest something larger, say 8*1024*1024, about 8MB to accommodate about 2 large page worth of data. Maybe that will further improve throughput on stress-ng by reducing contention on adding to the global count. Tim