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 1F8EEC3F6B0 for ; Thu, 25 Aug 2022 00:33:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229958AbiHYAdg (ORCPT ); Wed, 24 Aug 2022 20:33:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229490AbiHYAde (ORCPT ); Wed, 24 Aug 2022 20:33:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDE0E8C474; Wed, 24 Aug 2022 17:33:32 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 684ED61A78; Thu, 25 Aug 2022 00:33:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40059C433C1; Thu, 25 Aug 2022 00:33:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1661387611; bh=3yxsP6DawL5+lHuusAb977k18cNkRTLfgXocBtYSv1o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=oGJkgMPUbZFMjG8O/7KdMb+vxZpJH+5niJeB5INpD8x3qYjLkUAwWFAEXr5JNN1eo Zvf29lZuGkCpHP0RE/bBdynwQoc8oxWiELrbP6kyLDky2jSG7ggF/8yGnTB04Gjxo1 pMFYLznoGdT4pFmceHv0wgl291f+JjhUcTezFMoo= Date: Wed, 24 Aug 2022 17:33:30 -0700 From: Andrew Morton To: Shakeel Butt Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , =?ISO-8859-1?Q? "Michal_Koutn=FD" ?= , Eric Dumazet , Soheil Hassas Yeganeh , Feng Tang , Oliver Sang , lkp@lists.01.org, cgroups@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/3] mm: page_counter: rearrange struct page_counter fields Message-Id: <20220824173330.2a15bcda24d2c3c248bc43c7@linux-foundation.org> In-Reply-To: <20220825000506.239406-3-shakeelb@google.com> References: <20220825000506.239406-1-shakeelb@google.com> <20220825000506.239406-3-shakeelb@google.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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 Aug 2022 00:05:05 +0000 Shakeel Butt wrote: > With memcg v2 enabled, memcg->memory.usage is a very hot member for > the workloads doing memcg charging on multiple CPUs concurrently. > Particularly the network intensive workloads. In addition, there is a > false cache sharing between memory.usage and memory.high on the charge > path. This patch moves the usage into a separate cacheline and move all > the read most fields into separate cacheline. > > To evaluate the impact of this optimization, on a 72 CPUs machine, we > ran the following workload in a three level of cgroup hierarchy. > > $ netserver -6 > # 36 instances of netperf with following params > $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K > > Results (average throughput of netperf): > Without (6.0-rc1) 10482.7 Mbps > With patch 12413.7 Mbps (18.4% improvement) > > With the patch, the throughput improved by 18.4%. > > One side-effect of this patch is the increase in the size of struct > mem_cgroup. For example with this patch on 64 bit build, the size of > struct mem_cgroup increased from 4032 bytes to 4416 bytes. However for > the performance improvement, this additional size is worth it. In > addition there are opportunities to reduce the size of struct > mem_cgroup like deprecation of kmem and tcpmem page counters and > better packing. Did you evaluate the effects of using a per-cpu counter of some form?