From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933827AbYEGTZs (ORCPT ); Wed, 7 May 2008 15:25:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933392AbYEGTYs (ORCPT ); Wed, 7 May 2008 15:24:48 -0400 Received: from palinux.external.hp.com ([192.25.206.14]:56844 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765976AbYEGTYn (ORCPT ); Wed, 7 May 2008 15:24:43 -0400 Date: Wed, 7 May 2008 13:24:25 -0600 From: Matthew Wilcox To: Linus Torvalds Cc: Ingo Molnar , Andrew Morton , "J. Bruce Fields" , "Zhang, Yanmin" , LKML , Alexander Viro , linux-fsdevel@vger.kernel.org Subject: Re: AIM7 40% regression with 2.6.26-rc1 Message-ID: <20080507192425.GC19219@parisc-linux.org> References: <20080507172246.GA13262@elte.hu> <20080507174900.GB13591@elte.hu> <20080507181714.GA14980@elte.hu> <20080507184304.GA15554@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 07, 2008 at 12:01:28PM -0700, Linus Torvalds wrote: > The thing is, we definitely are interested to see whether it's the BKL or > some other semaphore that is the problem. But the best way to test that is > to just try my patch that *guarantees* that the BKL doesn't have any > semaphore behaviour AT ALL. > > Could it be something else entirely? Yes. We know it's semaphore- related. > We don't know for a fact that it's the BKL itself. There could be other > semaphores that are that hot. It sounds unlikely, but quite frankly, > regardless, I don't really see the point of your patches. > > If Yanmin tries my patch, it is *guaranteed* to show something. It either > shows that it's about the BKL (and that we absolutely have to do the BKL > as something _else_ than a generic semaphore), or it shows that it's not > about the BKL (and that _all_ the patches in this discussion are likely > pointless). One patch I'd still like Yanmin to test is my one from yesterday which removes the BKL from fs/locks.c. http://marc.info/?l=linux-fsdevel&m=121009123427437&w=2 Obviously, it won't help if the problem isn't the BKL. -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."