Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753913AbZALQrh (ORCPT ); Mon, 12 Jan 2009 11:47:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752642AbZALQrZ (ORCPT ); Mon, 12 Jan 2009 11:47:25 -0500 Received: from rcsinet12.oracle.com ([148.87.113.124]:48551 "EHLO rgminet12.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752619AbZALQrY (ORCPT ); Mon, 12 Jan 2009 11:47:24 -0500 Subject: Re: [PATCH -v8][RFC] mutex: implement adaptive spinning From: Chris Mason To: Linus Torvalds Cc: Peter Zijlstra , Ingo Molnar , "Paul E. McKenney" , Gregory Haskins , Matthew Wilcox , Andi Kleen , Andrew Morton , Linux Kernel Mailing List , linux-fsdevel , linux-btrfs , Thomas Gleixner , Nick Piggin , Peter Morreale , Sven Dietrich , Dmitry Adamushko In-Reply-To: References: <1231774622.4371.96.camel@laptop> Content-Type: text/plain Date: Mon, 12 Jan 2009 11:45:57 -0500 Message-Id: <1231778757.22806.24.camel@think.oraclecorp.com> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 Content-Transfer-Encoding: 7bit X-Source-IP: acsmt702.oracle.com [141.146.40.80] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090202.496B73D1.01F9:SCFSTAT928724,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1295 Lines: 36 On Mon, 2009-01-12 at 08:20 -0800, Linus Torvalds wrote: > > On Mon, 12 Jan 2009, Linus Torvalds wrote: > > > > You made it back into the locked version. > > Btw, even if you probably had some reason for this, one thing to note is > that I think Chris' performance testing showed that the version using a > lock was inferior to his local btrfs hack, while the unlocked version > actually beat his hack. > The spinning hack was faster than everything before v7 (we'll call it the Linus-fix), and the v7 code was much faster than my spin. This is somewhere in between, with slightly better fairness than v7. spin v7 v8 dbench 50 580MB/s 789MB/s 421MB/s file creates 152 file/s 162 file/s 195 file/s file stat 3.8s total 2.3s total 5.3s total (the file stat run is total run time, so lower is better. The other numbers are files or MB per second, so higher is better) For the file create run, v8 had much lower system time than v7, averaging 1s of sys time per proc instead of 1.6s. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/