From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: Fwd: Re: RFC: cgroups aware proc Date: Mon, 13 Jan 2014 18:12:38 +0100 Message-ID: <20140113171238.GS31570@twins.programming.kicks-ass.net> References: <52D35CD0.9070602@huawei.com> <52D41316.5080508@yuhu.biz> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <52D41316.5080508@yuhu.biz> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Marian Marinov Cc: lxc-devel@lists.linuxcontainers.org, cgroups@vger.kernel.org, "Daniel P. Berrange" , Serge Hallyn , Li Zefan , Ingo Molnar , linux-kernel@vger.kernel.org On Mon, Jan 13, 2014 at 06:23:50PM +0200, Marian Marinov wrote: > Hello Peter, > > I need help with the scheduler. > > I'm currently trying to patch the /proc/loadavg to show the load that is > only related to the processes from the current cgroup. > > I looked trough the code and I was hoping that tsk->sched_task_group->cfs_rq > struct will give me the needed information, but unfortunately for me, it did > not. > > Can you advise me, how to approach this problem? Yeah, don't :-) Really, loadavg is a stupid metric. > I'm totally new to the scheduler code. Luckily you won't actually have to touch much of it. Most of the actual loadavg code lives in the first ~400 lines of kernel/sched/proc.c, read and weep. Its one of the best documented bits around. Your proposition however is extremely expensive, you turn something that's already expensive O(nr_cpus) into something O(nr_cpus * nr_cgroups). I'm fairly sure people will not like that, esp. for something of such questionable use as the loadavg -- its really only a pretty number that doesn't mean all that much. > -------- Original Message -------- > From: Li Zefan > > Then you should add Peter, Ingo and LKML to your Cc list. :) You failed that, let me fix that.