From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753482AbcGVBSG (ORCPT ); Thu, 21 Jul 2016 21:18:06 -0400 Received: from mail-wm0-f44.google.com ([74.125.82.44]:35456 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753248AbcGVBSE (ORCPT ); Thu, 21 Jul 2016 21:18:04 -0400 MIME-Version: 1.0 In-Reply-To: References: From: Gaurav Poothia Date: Thu, 21 Jul 2016 18:18:01 -0700 Message-ID: Subject: Re: Question about group scheduler cpu shares To: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +Ingo, Peter On Thu, Jul 21, 2016 at 12:03 PM, Gaurav Poothia wrote: > Hi, > The cgroup "cpu" subsystem's weight calculation using "cpu shares" is > fairly clear when all tasks are attached to the leaf cgroups in "cpu" > subsystem. > For example in this cgroup hierarchy with tasks A.B,C and D and > associated cpu shares: > > ROOT > | > + -Group1(3072) > | | > | +- A(2048) > | | > | +- B(1024) > | > +- Group2(2048) > | > +-C(1024) > | > +-D(1024) > > Group 1 and Group 2 split the CPU 60% to 40% respectively > A and B split Group1's 60% share 2/3rd to 1/3rd so absolute share of > CPU will be 40% and 20% respectively > C and D split Group2's 40% share evenly so absolute shares or 20% each > So far so good. But in this example all tasks are associated with leaf cgroups. > > Say I add a task E to Group1's task list (note that is an interior aka > non-leaf node) > How does the CPU split change between A, B and E. > AFAICT there is no cgroup cpu subsystem knob to weight tasks on an > interior node against the tasks in that node's children > > Thanks in advance! > Gaurav -- Kiva.org - Loans That Change Lives