Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758643Ab3HORkG (ORCPT ); Thu, 15 Aug 2013 13:40:06 -0400 Received: from merlin.infradead.org ([205.233.59.134]:59283 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752690Ab3HORkE (ORCPT ); Thu, 15 Aug 2013 13:40:04 -0400 Date: Thu, 15 Aug 2013 19:39:53 +0200 From: Peter Zijlstra To: Paul Turner Cc: Lei Wen , LKML , Ingo Molnar , Lei Wen Subject: Re: false nr_running check in load balance? Message-ID: <20130815173953.GU24092@twins.programming.kicks-ass.net> References: <20130812144309.GK27162@twins.programming.kicks-ass.net> <20130813073842.GP27162@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1070 Lines: 25 On Tue, Aug 13, 2013 at 01:08:17AM -0700, Paul Turner wrote: > On Tue, Aug 13, 2013 at 12:38 AM, Peter Zijlstra wrote: > > On Tue, Aug 13, 2013 at 12:45:12PM +0800, Lei Wen wrote: > >> > Not quite right; I think you need busiest->cfs.h_nr_running. > >> > cfs.nr_running is the number of entries running in this 'group'. If > >> > you've got nested groups like: > >> > > >> > 'root' > >> > \ > >> > 'A' > >> > / \ > >> > t1 t2 > >> > > >> > root.nr_running := 1 'A', even though you've got multiple running tasks. One thing though; doesn't h_nr_running over count the number of tasks? That is, doesn't it count the runnable entities so the above case would give root.h_nr_running := 3, where we would only have 2 runnable tasks. Double check this and be careful when doing the conversion. -- 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/