From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756517Ab3AHOmv (ORCPT ); Tue, 8 Jan 2013 09:42:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:62847 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756428Ab3AHOmt (ORCPT ); Tue, 8 Jan 2013 09:42:49 -0500 Date: Tue, 8 Jan 2013 09:42:40 -0500 From: Vivek Goyal To: Tejun Heo Cc: lizefan@huawei.com, axboe@kernel.dk, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, ctalbott@google.com, rni@google.com Subject: Re: [PATCH UPDATED 15/24] cfq-iosched: enable full blkcg hierarchy support Message-ID: <20130108144240.GA29635@redhat.com> References: <1356726946-26037-1-git-send-email-tj@kernel.org> <1356726946-26037-16-git-send-email-tj@kernel.org> <20130107163405.GE3926@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130107163405.GE3926@htj.dyndns.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 07, 2013 at 08:34:05AM -0800, Tejun Heo wrote: [..] > + weight leaf_weight > + root : 125 125 > + A : 500 750 > + B : 250 500 > + AA : 500 500 > + AB : 1000 500 > + > +root never has a parent making its weight is meaningless. For backward > +compatibility, weight is always kept in sync with leaf_weight. B, AA > +and AB have no child and thus its tasks have no children cgroup to > +compete with. They always get 100% of what the cgroup won at the > +parent level. Considering only the weights which matter, the hierarchy > +looks like the following. > + > + root > + / | \ > + A B leaf > + 500 250 125 > + / | \ > + AA AB leaf > + 500 1000 750 > + > +If all cgroups have active IOs and competing with each other, disk > +time will be distributed like the following. > + > +Distribution below root. The total active weight at this level is > +A:500 + B:250 + C:125 = 875. > + > + root-leaf : 125 / 875 =~ 14% > + A : 500 / 875 =~ 57% > + B(-leaf) : 250 / 875 =~ 28% > + > +A has children and further distributes its 57% among the children and > +the implicit leaf node. The total active weight at this level is > +AA:500 + AB:1000 + A-leaf:750 = 2250. > + > + A-leaf : ( 750 / 2250) * A =~ 19% > + AA(-leaf) : ( 500 / 2250) * A =~ 12% > + AB(-leaf) : (1000 / 2250) * A =~ 25% Hi Tejun, What does (-leaf) is supposed to signify? I can understand that A-leaf tells the share of A's tasks which are effectively in A-leaf group. Will just plain AA and AB be more clear? Rest looks good to me. Thanks for updating the blkio-controoler.txt too. Thanks Vivek