From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: [tbench regression fixes]: digging out smelly deadmen. Date: Sun, 26 Oct 2008 10:15:46 +0100 Message-ID: <1225012546.8566.33.camel@marge.simson.net> References: <20081024.221653.23695396.davem@davemloft.net> <1224914333.3822.18.camel@marge.simson.net> <1224917623.4929.15.camel@marge.simson.net> <20081025.002420.82739316.davem@davemloft.net> <1225010790.8566.22.camel@marge.simson.net> <1225011648.27415.4.camel@twins> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Jiri Kosina , David Miller , rjw@sisk.pl, Ingo Molnar , s0mbre@tservice.net.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Andrew Morton To: Peter Zijlstra Return-path: Received: from mail.gmx.net ([213.165.64.20]:45743 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751025AbYJZJPv (ORCPT ); Sun, 26 Oct 2008 05:15:51 -0400 In-Reply-To: <1225011648.27415.4.camel@twins> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, 2008-10-26 at 10:00 +0100, Peter Zijlstra wrote: > On Sun, 2008-10-26 at 09:46 +0100, Mike Galbraith wrote: > > I reproduced this on my Q6600 box. However, I also reproduced it with > > 2.6.22.19. What I think you're seeing is just dbench creating a > > massive train wreck. > > wasn't dbench one of those non-benchmarks that thrives on randomness and > unfairness? > > Andrew said recently: > "dbench is pretty chaotic and it could be that a good change causes > dbench to get worse. That's happened plenty of times in the past." > > So I'm not inclined to worry too much about dbench in any way shape or > form. Yeah, I was just curious. The switch rate of dbench isn't high enough for math to be an issue, so I wondered how the heck CFS could be such a huge problem for this load. Looks to me like all the math in the _world_ couldn't hurt.. or help. -Mike