From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [tbench regression fixes]: digging out smelly deadmen. Date: Sun, 26 Oct 2008 12:27:22 +0300 Message-ID: <20081026092722.GA24799@ioremap.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> <20081026021153.47878580.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Peter Zijlstra , Mike Galbraith , Jiri Kosina , David Miller , rjw@sisk.pl, Ingo Molnar , s0mbre@tservice.net.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Andrew Morton Return-path: Received: from broadrack.ru ([195.178.208.66]:52701 "EHLO tservice.net.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751089AbYJZJ1Z (ORCPT ); Sun, 26 Oct 2008 05:27:25 -0400 Content-Disposition: inline In-Reply-To: <20081026021153.47878580.akpm@linux-foundation.org> Sender: netdev-owner@vger.kernel.org List-ID: Hi. On Sun, Oct 26, 2008 at 02:11:53AM -0700, Andrew Morton (akpm@linux-foundation.org) wrote: > > 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. > > Well. If there is a consistent change in dbench throughput, it is > important that we at least understand the reasons for it. But we > don't necessarily want to optimise for dbench throughput. Sorry, but such excuses do not deserve to be said. No matter how ugly, wrong, unusual or whatever else you might say about some test, but it shows the problem, which has to be fixed. There is no 'dbench tune', there is fair number of problems, and at least several of them dbench already helped to narrow down and precisely locate. The same regressions were also observed in other benchmarks, originally reported before I started this thread. -- Evgeniy Polyakov