From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966694AbcAZQ0M (ORCPT ); Tue, 26 Jan 2016 11:26:12 -0500 Received: from resqmta-ch2-04v.sys.comcast.net ([69.252.207.36]:49365 "EHLO resqmta-ch2-04v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966230AbcAZQ0G (ORCPT ); Tue, 26 Jan 2016 11:26:06 -0500 Date: Tue, 26 Jan 2016 10:26:04 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@east.gentwo.org To: Mike Galbraith cc: Michal Hocko , Peter Zijlstra , LKML Subject: Re: fast path cycle muncher (vmstat: make vmstat_updater deferrable again and shut down on idle) In-Reply-To: <1453774465.3642.13.camel@gmail.com> Message-ID: References: <20160121082402.GA29520@dhcp22.suse.cz> <20160121165148.GF29520@dhcp22.suse.cz> <20160122140418.GB19465@dhcp22.suse.cz> <20160122161201.GC19465@dhcp22.suse.cz> <1453566115.3529.8.camel@gmail.com> <20160125174224.GH23934@dhcp22.suse.cz> <1453774465.3642.13.camel@gmail.com> Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Jan 2016, Mike Galbraith wrote: > > Why would the deferring cause this overhead? > > Because we schedule to idle cores aggressively, thus we may pop in and > out of idle at high frequency. Whats the point of going idle if you have things to do soon?