Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755262Ab1BXPxi (ORCPT ); Thu, 24 Feb 2011 10:53:38 -0500 Received: from casper.infradead.org ([85.118.1.10]:33826 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752306Ab1BXPxh convert rfc822-to-8bit (ORCPT ); Thu, 24 Feb 2011 10:53:37 -0500 Subject: Re: [CFS Bandwidth Control v4 3/7] sched: throttle cfs_rq entities which exceed their local quota From: Peter Zijlstra To: bharata@linux.vnet.ibm.com Cc: Paul Turner , linux-kernel@vger.kernel.org, Dhaval Giani , Balbir Singh , Vaidyanathan Srinivasan , Srivatsa Vaddagiri , Kamalesh Babulal , Ingo Molnar , Pavel Emelyanov , Herbert Poetzl , Avi Kivity , Chris Friesen , Nikhil Rao In-Reply-To: <20110224154547.GA3000@in.ibm.com> References: <20110216031831.571628191@google.com> <20110216031841.068673650@google.com> <1298467933.2217.765.camel@twins> <20110224052101.GA2755@in.ibm.com> <1298545501.2428.18.camel@twins> <20110224154547.GA3000@in.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Thu, 24 Feb 2011 16:52:53 +0100 Message-ID: <1298562773.2428.230.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 979 Lines: 19 On Thu, 2011-02-24 at 21:15 +0530, Bharata B Rao wrote: > While I admit that our load balancing semantics wrt thorttled entities are > not consistent (we don't allow pulling of tasks directly from throttled > cfs_rqs, while allow pulling of tasks from a throttled hierarchy as in the > above case), I am beginning to think if it works out to be advantageous. > Is there a chance that the task gets to run on other CPU where the hierarchy > isn't throttled since runtime is still available ? Possible yes, but the load-balancer doesn't know about that, not should it (its complicated, and broken, enough, no need to add more cruft to it). I'm starting to think you all should just toss all this and start over, its just too smelly. -- 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/