From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: [PATCH 00/14] per memcg lru_lock Date: Thu, 22 Aug 2019 19:56:59 +0800 Message-ID: <348495d2-b558-fdfd-a411-89c75d4a9c78@linux.alibaba.com> References: <1566294517-86418-1-git-send-email-alex.shi@linux.alibaba.com> <6ba1ffb0-fce0-c590-c373-7cbc516dbebd@oracle.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <6ba1ffb0-fce0-c590-c373-7cbc516dbebd@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="utf-8" To: Daniel Jordan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Mel Gorman , Tejun Heo , Michal Hocko 在 2019/8/22 上午2:00, Daniel Jordan 写道: >> > > This is system-wide right, not per container?  Even per container, 89 usec isn't much contention over 20 seconds.  You may want to give this a try: yes, perf lock show the host info. > >   https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice> > It's also synthetic but it stresses lru_lock more than just anon alloc/free.  It hits the page activate path, which is where we see this lock in our database, and if enough memory is configured lru_lock also gets stressed during reclaim, similar to [1]. Thanks for the sharing, this patchset can not help the [1] case, since it's just relief the per container lock contention now. Yes, readtwice case could be more sensitive for this lru_lock changes in containers. I may try to use it in container with some tuning. But anyway, aim9 is also pretty good to show the problem and solutions. :) > > It'd be better though, as Michal suggests, to use the real workload that's causing problems.  Where are you seeing contention? We repeatly create or delete a lot of different containers according to servers load/usage, so normal workload could cause lots of pages alloc/remove. aim9 could reflect part of scenarios. I don't know the DB scenario yet. > >> With this patch series, lruvec->lru_lock show no contentions >>          &(&lruvec->lru_l...          8          0               0       0               0               0 >> >> and aim9 page_test/brk_test performance increased 5%~50%. > > Where does the 50% number come in?  The numbers below seem to only show ~4% boost. the Setddev/CoeffVar case has about 50% performance increase. one of container's mmtests result as following: Stddev page_test 245.15 ( 0.00%) 189.29 ( 22.79%) Stddev brk_test 1258.60 ( 0.00%) 629.16 ( 50.01%) CoeffVar page_test 0.71 ( 0.00%) 0.53 ( 26.05%) CoeffVar brk_test 1.32 ( 0.00%) 0.64 ( 51.14%)