From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965125AbWEYMEo (ORCPT ); Thu, 25 May 2006 08:04:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965126AbWEYMEo (ORCPT ); Thu, 25 May 2006 08:04:44 -0400 Received: from ns.mipt.ru ([193.125.143.173]:37848 "EHLO mail.telecom.mipt.ru") by vger.kernel.org with ESMTP id S965125AbWEYMEo (ORCPT ); Thu, 25 May 2006 08:04:44 -0400 Message-ID: <44758D79.3020302@sw.ru> Date: Thu, 25 May 2006 14:56:57 +0400 From: Vasily Tarasov Reply-To: vtaras@sw.ru Organization: SWSoft User-Agent: Mozilla Thunderbird 1.0.7 (X11/20051208) X-Accept-Language: en-us, en MIME-Version: 1.0 To: axboe@suse.de CC: linux-kernel@vger.kernel.org, Kirill Korotaev Subject: ioprio feature behaviour Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello. I produced a little test of ioprio feature. Results are basically good enough, but there is something strange on my mind. The test just runs 8 simple readers with priorities 0, 1, .., 7 in best effort class. Readers read from files and count how much Mbytes per second they can read. Results are here: Process # (prio) Measurement 1 (Mbps) Measurement 2 (Mbps) Measurement 3 (Mbps) 0 6,60 7,37 6,19 1 7,87 7,90 7,15 2 5,92 4,75 4,61 3 3,31 3,34 3,4 4 0,95 0,97 1,03 5 1,14 1,23 1,2 6 0,83 0,96 0,83 7 0,41 0,41 0,41 ( The whole results are at http://www.7ka.mipt.ru/~vass/cfq-tests/tests.pdf) The questions are: 1) Why process 0 with priority 0 has less bandwidth than process 1 with priority 1? 2) The same with processes (priorities) 4, 5? 3) Why there is no _uniform_ dependence between bandwidth and priority? 4) Why sums of bandwidths of processes when priorities are setted and when they are not setted (look in pdf) aren't equal? Thanks, Vasily.