From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964883Ab2KAPwd (ORCPT ); Thu, 1 Nov 2012 11:52:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:48605 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964826Ab2KAPwa (ORCPT ); Thu, 1 Nov 2012 11:52:30 -0400 Date: Thu, 1 Nov 2012 15:52:26 +0000 From: Mel Gorman To: Peter Zijlstra Cc: Rik van Riel , Andrea Arcangeli , Johannes Weiner , Thomas Gleixner , Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar Subject: Re: [PATCH 30/31] sched, numa, mm: Implement slow start for working set sampling Message-ID: <20121101155226.GE3888@suse.de> References: <20121025121617.617683848@chello.nl> <20121025124834.720647725@chello.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20121025124834.720647725@chello.nl> 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 Thu, Oct 25, 2012 at 02:16:47PM +0200, Peter Zijlstra wrote: > Add a 1 second delay before starting to scan the working set of > a task and starting to balance it amongst nodes. > > [ note that before the constant per task WSS sampling rate patch > the initial scan would happen much later still, in effect that > patch caused this regression. ] > > The theory is that short-run tasks benefit very little from NUMA > placement: they come and go, and they better stick to the node > they were started on. As tasks mature and rebalance to other CPUs > and nodes, so does their NUMA placement have to change and so > does it start to matter more and more. > Yeah, ok. It's done by wall time, right? Should it be CPU time in case it spent the first second asleep? -- Mel Gorman SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx174.postini.com [74.125.245.174]) by kanga.kvack.org (Postfix) with SMTP id A30D06B0062 for ; Thu, 1 Nov 2012 11:52:32 -0400 (EDT) Date: Thu, 1 Nov 2012 15:52:26 +0000 From: Mel Gorman Subject: Re: [PATCH 30/31] sched, numa, mm: Implement slow start for working set sampling Message-ID: <20121101155226.GE3888@suse.de> References: <20121025121617.617683848@chello.nl> <20121025124834.720647725@chello.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20121025124834.720647725@chello.nl> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Rik van Riel , Andrea Arcangeli , Johannes Weiner , Thomas Gleixner , Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar On Thu, Oct 25, 2012 at 02:16:47PM +0200, Peter Zijlstra wrote: > Add a 1 second delay before starting to scan the working set of > a task and starting to balance it amongst nodes. > > [ note that before the constant per task WSS sampling rate patch > the initial scan would happen much later still, in effect that > patch caused this regression. ] > > The theory is that short-run tasks benefit very little from NUMA > placement: they come and go, and they better stick to the node > they were started on. As tasks mature and rebalance to other CPUs > and nodes, so does their NUMA placement have to change and so > does it start to matter more and more. > Yeah, ok. It's done by wall time, right? Should it be CPU time in case it spent the first second asleep? -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org