From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx163.postini.com [74.125.245.163]) by kanga.kvack.org (Postfix) with SMTP id 865DC6B0033 for ; Tue, 18 Jun 2013 11:23:39 -0400 (EDT) Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 18 Jun 2013 11:23:38 -0400 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id E1D9B38C8059 for ; Tue, 18 Jun 2013 11:23:34 -0400 (EDT) Received: from d03av06.boulder.ibm.com (d03av06.boulder.ibm.com [9.17.195.245]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5IFNZ4G244994 for ; Tue, 18 Jun 2013 11:23:35 -0400 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 r5IFPTP5003141 for ; Tue, 18 Jun 2013 09:25:29 -0600 Date: Tue, 18 Jun 2013 08:23:02 -0700 From: "Paul E. McKenney" Subject: vmstat kthreads Message-ID: <20130618152302.GA10702@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: ghaskins@londonstockexchange.com, niv@us.ibm.com, kravetz@us.ibm.com Hello! 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. Does this seem like a sensible course of action, or did I miss something when I went through the code? 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