From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750964Ab2C1FMw (ORCPT ); Wed, 28 Mar 2012 01:12:52 -0400 Received: from moutng.kundenserver.de ([212.227.17.8]:52313 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750746Ab2C1FMv (ORCPT ); Wed, 28 Mar 2012 01:12:51 -0400 Date: Wed, 28 Mar 2012 07:12:43 +0200 From: Heinz Diehl To: linux-kernel@vger.kernel.org Subject: Re: [ANNOUNCE] BFS CPU scheduler version 0.420 AKA "Smoking" for linux kernel 3.3.0 Message-ID: <20120328051243.GA2138@fancy-poultry.org> References: <201203240553.32526.gene.heskett@gmail.com> <57375.1332641134@turing-police.cc.vt.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57375.1332641134@turing-police.cc.vt.edu> Organization: private site X-OpenPGP-KeyID: 0x898F89DE X-OpenPGP-Fingerprint: 0815 20AD E896 A2B7 488F 4659 4C7B 8951 898F 89DE X-OpenPGP-URL: http://www.fritha.org/htd.asc User-Agent: Mutt/1.5.21+52 (c26dbc7021f4) (2011-07-01) X-Provags-ID: V02:K0:aGCP0TkB3MK1zTzYyjdTpAHGZcVsNlpnv9BKgbNdXLw As9aF8mjkgl/SGTap+vbC5cPBGKqmjBaOGCcG43Up7/1VyY+TL EKK7EVSoGMXHfv2FQ9tEugEiLdKwkydKybcH07oFAH1P+4igUm zg3j9P9cd9ZGqCT2XvgAYaK2nRl81xF/TArPmOaLjqZcu0PUOm wNw0SNFUNAKEKW5u+GEaXgoG7OAjEH9yqkkHcjXnLMBDl8OcAA x/TumLLW0jwpMlxQVMbmVEqgxdBz228vj719RsHXx14TnfcCSI vUHZQQhixICQiI8HbldbyG1R6xYKO0uEwWqTNcmn2WiUyH/abd fB3zWSi9BuhUO4RXcgCiF8FeSJMDKGa0T6kOy5pg1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25.03.2012, Valdis.Kletnieks@vt.edu wrote: > I'va always wondered what people are using to measure interactivity. Do we have > some hard numbers from scheduler traces, or is it a "feels faster"? I guess it's a "feels faster", because it's the only thing that counts. Given that there is strong evidence that scheduler A is "faster, more interactive", whatever... than scheduler B, but a controlled trial shows a significantly better "feels faster" experience using scheduler B, I'm quite shure that people would choose scheduler B over A, and that's quite ok. It does what they expect it to do, despite evidence which documents the opposite. > And if it's a subjective thing, how are people avoiding confirmation bias (where you > decide it feels faster because it's the new kernel and *should* feel faster)? Confirmation bias is one thing, and it does exist. Surely. So it's up to the user if it wants evidence, or if it's enough that it feels faster. I guess that evidence doesn't really matter for the most of the users as long as they have a positive experience. > Anybody doing blinded boots, where a random kernel old/new is booted and the > user grades the performance without knowing which one was actually running? Hey, we could construct a randomized controlled trial on this :-) > And yes, this can be a real issue - anybody who's been a aysadmin for > a while will have at least one story of scheduling an upgrade, scratching it > at the last minute, and then having users complain about how the upgrade > ruined performance and introduced bugs... Yep. They who have to do "real work" will rather base it on evidence than trust their own feelings.