From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756754Ab0DARDQ (ORCPT ); Thu, 1 Apr 2010 13:03:16 -0400 Received: from sous-sol.org ([216.99.217.87]:44062 "EHLO sequoia.sous-sol.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755864Ab0DARDJ (ORCPT ); Thu, 1 Apr 2010 13:03:09 -0400 Date: Thu, 1 Apr 2010 10:02:30 -0700 From: Chris Wright To: Darren Hart Cc: Roland Dreier , "lkml, " , Steven Rostedt , Peter Zijlstra , Gregory Haskins , Sven-Thorsten Dietrich , Peter Morreale , Chris Wright , Thomas Gleixner , Ingo Molnar , Eric Dumazet Subject: Re: RFC: Ideal Adaptive Spinning Conditions Message-ID: <20100401170230.GW29241@sequoia.sous-sol.org> References: <4BB3D90C.3030108@us.ibm.com> <4BB3FF03.7060400@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BB3FF03.7060400@us.ibm.com> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Darren Hart (dvhltc@us.ibm.com) wrote: > Roland Dreier wrote: >> > I'm looking at some adaptive spinning with futexes as a way to help >> > reduce the dependence on sched_yield() to implement userspace >> > spinlocks. Chris, I included you in the CC after reading your comments >> > regarding sched_yield() at kernel summit and I thought you might be >> > interested. >> >> I think you may have the wrong Chris. Chris Wright wasn't at the most >> recent kernel summit and I do have a vague recollection of Chris Mason >> mentioning that Oracle developers found that sched_yield() performed >> better than futexes + kernel scheduling. > > Oh bother, Sorry Chris! I even talked to Chris Wright about this already > in person and he told me I probably was looking for Chris Mason, and I > still got the last names crossed up! No worries Darren, I happen to be interested in the topic too ;-) (from KVM point of view, which has a slightly different take)