Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760478AbXKMHaZ (ORCPT ); Tue, 13 Nov 2007 02:30:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751786AbXKMHaM (ORCPT ); Tue, 13 Nov 2007 02:30:12 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:34372 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752102AbXKMHaK (ORCPT ); Tue, 13 Nov 2007 02:30:10 -0500 Message-ID: <47395277.1060006@linux.vnet.ibm.com> Date: Tue, 13 Nov 2007 12:59:59 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 1.5.0.13 (X11/20070824) MIME-Version: 1.0 To: Paul Menage CC: containers@lists.linux-foundation.org, vatsa@linux.vnet.ibm.com, LKML , Ingo Molnar , Linus Torvalds , Andrew Morton Subject: Re: Revert for cgroups CPU accounting subsystem patch References: <6599ad830711122125u576e85a6w428466a0ab46dbc6@mail.gmail.com> <20071113060038.GC3359@linux.vnet.ibm.com> <6599ad830711122205g88aae4fua8dd76cf6e8ab84d@mail.gmail.com> <47394B84.8030008@linux.vnet.ibm.com> <6599ad830711122310nf7530cfs5ef1fea061b1252c@mail.gmail.com> In-Reply-To: <6599ad830711122310nf7530cfs5ef1fea061b1252c@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1408 Lines: 38 Paul Menage wrote: > On Nov 12, 2007 11:00 PM, Balbir Singh wrote: >> Right now, one of the limitations of the CPU controller is that >> the moment you create another control group, the bandwidth gets >> divided by the default number of shares. We can't create groups >> just for monitoring. > > Could we get around this with, say, a flag that always treats a CFS > schedulable entity as having a weight equal to the number of runnable > tasks in it? So CPU bandwidth would be shared between groups in > proportion to the number of runnable tasks, which would distribute the > cycles approximately equivalently to them all being separate > schedulable entities. > I think it's a good hack, but not sure about the complexity to implement the code. I worry that if the number of tasks increase (say run into thousands for one or more groups and a few groups have just a few tasks), we'll lose out on accuracy. >> cpu_acct fills this gap. > > Agreed, but not in the right way IMO. > I think we already have the code, we need to make it more useful and reusable. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/