From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx157.postini.com [74.125.245.157]) by kanga.kvack.org (Postfix) with SMTP id BDC346B0033 for ; Tue, 18 Jun 2013 14:27:04 -0400 (EDT) Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 18 Jun 2013 12:26:24 -0600 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 546C41FF001E for ; Tue, 18 Jun 2013 12:21:03 -0600 (MDT) Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5IIQHHA219542 for ; Tue, 18 Jun 2013 12:26:17 -0600 Received: from d03av06.boulder.ibm.com (loopback [127.0.0.1]) by d03av06.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5IISgoP013858 for ; Tue, 18 Jun 2013 12:28:42 -0600 Date: Tue, 18 Jun 2013 11:26:16 -0700 From: "Paul E. McKenney" Subject: Re: vmstat kthreads Message-ID: <20130618182616.GT5146@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130618152302.GA10702@linux.vnet.ibm.com> <0000013f58656ee7-8bb24ac4-72fa-4c0b-b888-7c056f261b6e-000000@email.amazonses.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000013f58656ee7-8bb24ac4-72fa-4c0b-b888-7c056f261b6e-000000@email.amazonses.com> Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: gilad@benyossef.com, linux-mm@kvack.org, ghaskins@londonstockexchange.com, niv@us.ibm.com, kravetz@us.ibm.com On Tue, Jun 18, 2013 at 05:46:50PM +0000, Christoph Lameter wrote: > On Tue, 18 Jun 2013, Paul E. McKenney wrote: > > > I have been digging around the vmstat kthreads a bit, and it appears to > > me that there is no reason to run a given CPU's vmstat kthread unless > > that CPU spends some time executing in the kernel. If correct, this > > observation indicates that one way to safely reduce OS jitter due to the > > vmstat kthreads is to prevent them from executing on a given CPU if that > > CPU has been executing in usermode since the last time that this CPU's > > vmstat kthread executed. > > Right and we have patches to that effect. Even better! > > Does this seem like a sensible course of action, or did I miss something > > when I went through the code? > > Nope you are right on. > > Gilad Ben-Yossef has been posting patches that address this issue in Feb > 2012. Ccing him. Can we see your latest work, Gilead? Is it this one? https://lkml.org/lkml/2012/5/3/269 Thanx, Paul -- 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