From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751149AbdBLHA6 (ORCPT ); Sun, 12 Feb 2017 02:00:58 -0500 Received: from mout.gmx.net ([212.227.15.19]:61543 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780AbdBLHA4 (ORCPT ); Sun, 12 Feb 2017 02:00:56 -0500 Message-ID: <1486882799.24462.25.camel@gmx.de> Subject: Re: [PATCHSET for-4.11] cgroup: implement cgroup v2 thread mode From: Mike Galbraith To: Tejun Heo , Peter Zijlstra Cc: lizefan@huawei.com, hannes@cmpxchg.org, mingo@redhat.com, pjt@google.com, luto@amacapital.net, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, lvenanci@redhat.com, Linus Torvalds , Andrew Morton Date: Sun, 12 Feb 2017 07:59:59 +0100 In-Reply-To: <20170212050544.GJ29323@mtj.duckdns.org> References: <20170202200632.13992-1-tj@kernel.org> <20170203202048.GD6515@twins.programming.kicks-ass.net> <20170203205955.GA9886@mtj.duckdns.org> <20170206124943.GJ6515@twins.programming.kicks-ass.net> <20170208230819.GD25826@htj.duckdns.org> <20170209102909.GC6515@twins.programming.kicks-ass.net> <20170210154508.GA16097@mtj.duckdns.org> <20170210175145.GJ6515@twins.programming.kicks-ass.net> <20170212050544.GJ29323@mtj.duckdns.org> Content-Type: text/plain; charset="us-ascii" X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:V7cfMGQbeQoemdV2fESTjiOAFC3sd1lTtrkzZwrEhlJ6sxO9qgD AyXawb/AIeYmumH/aVHJ5utqxERPA7o+2YZLPej96OwcLcYK3ih+9Vf1UjYCusIEOfYgaJL BqqfJQ1GMGUPdoxmX/bqcXsU+QfXBHmC1WjuvtKYsELiRK/UcwKUJE+QNSXTv3PLbwPrMjW arX48AqhRVjjGCN4ZpmVQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:ADtKQthAD5E=:gQpGS4F+Ki0viunLP6UhRG LX0fBDWR8//snhWVAine35uXg2B/KaAdpY0NQnN3lx61tICdJ5kP04sBmgt6zPXUCN6B0IGzp Sc+v2FETmTo4NfKTEh9tAJSpqLbnbJx9iHUDSGer60eRZ8RYxu4jduzpPOtYf16EVftNgTKCB 1XYYGT+hwHK5H+mlbxvAEYogoiexIz8RL8kDNtGWmWsgbuSrfo0qnBy32ynD1vuT8WoBxuVRv FsP6D6E9NEwwZWBvrH1QQ8BdGQ7zQxGu12hI/LeYveus9ConWz1LO9K0s+4c3lzQXiNtApJV/ jWyNFRC4dlptqVaCGFavbl7auqDJTAfcom20HS5W5Be5ZjkU4Suw6MsGm8jFxeHbMfzgTRNIi henAmLn8HnJNxar4RWAAL0yWhdXOrnEEkbJoSZlsh2gMuFoVr6cLjhXHSs80bNzsNy0G4qMD1 Zo4nOg/MqUpi4eITMWdZHkTxge2Qo4XI3hItnwVwrW/F3ZJDao2h6hUqmPm8Z/nlu981Zo3UH r0myJk47xZBA4PjmUtVgIjPfTOViz+LZVFWdzo4Ut/YvTN5S8LLrrDPL2FHX8BtegQjx+O22T P0P3887ARDFtWJyDHtj+2UWuk/Hor1Ggv5lYy1WbEecYLlPo6B3UfINtZAnhgSeht+pVTGepO KcC4xAKkgH5vBZ7YN497aevlWPPfwJteZidQfCkqBO6/bqiJWc4q8j75DCN7VReEtuzvAYnu1 BbkNbJzoGZ5WymFFzcrJkRhDA2YQfWDnYV2gOnUA9R7u9tySoCM8EogW2cg0ZmSenDOoXDkyp Ttc96FB Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2017-02-12 at 14:05 +0900, Tejun Heo wrote: > > I think cgroup tree depth is a more significant issue; because of > > hierarchy we often do tree walks (uo-to-root or down-to-task). > > > > So creating elaborate trees is something I try not to do. > > So, as long as the depth stays reasonable (single digit or lower), > what we try to do is keeping tree traversal operations aggregated or > located on slow paths. There still are places that this overhead > shows up (e.g. the block controllers aren't too optimized) but it > isn't particularly difficult to make a handful of layers not matter at > all. A handful of cpu bean counting layers stings considerably. homer:/abuild # pipe-test 1 2.010057 usecs/loop -- avg 2.010057 995.0 KHz 2.006630 usecs/loop -- avg 2.009714 995.2 KHz 2.127118 usecs/loop -- avg 2.021455 989.4 KHz 2.256244 usecs/loop -- avg 2.044934 978.0 KHz 1.993693 usecs/loop -- avg 2.039810 980.5 KHz ^C homer:/abuild # cgexec -g cpu:hurt pipe-test 1 2.771641 usecs/loop -- avg 2.771641 721.6 KHz 2.432333 usecs/loop -- avg 2.737710 730.5 KHz 2.750493 usecs/loop -- avg 2.738988 730.2 KHz 2.663203 usecs/loop -- avg 2.731410 732.2 KHz 2.762564 usecs/loop -- avg 2.734525 731.4 KHz ^C homer:/abuild # cgexec -g cpu:hurt/pain pipe-test 1 2.967201 usecs/loop -- avg 2.967201 674.0 KHz 3.049012 usecs/loop -- avg 2.975382 672.2 KHz 3.031226 usecs/loop -- avg 2.980966 670.9 KHz 2.954259 usecs/loop -- avg 2.978296 671.5 KHz 2.933432 usecs/loop -- avg 2.973809 672.5 KHz ^C ... homer:/abuild # cgexec -g cpu:hurt/pain/ouch/moan/groan pipe-test 1 4.417044 usecs/loop -- avg 4.417044 452.8 KHz 4.494913 usecs/loop -- avg 4.424831 452.0 KHz 4.253861 usecs/loop -- avg 4.407734 453.7 KHz 4.378059 usecs/loop -- avg 4.404766 454.1 KHz 4.179895 usecs/loop -- avg 4.382279 456.4 KHz