From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755701Ab0EFHfL (ORCPT ); Thu, 6 May 2010 03:35:11 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:55069 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755448Ab0EFHfI (ORCPT ); Thu, 6 May 2010 03:35:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=I/PYQUHKBjQjiaiqSSW8WyXtEYXDDuBW/zT+z6i8X9OlwMEnANBPbSwwLF9by79btH ZtUhTN/vip3sN+nYYTV0u7jBg9U5u2AUh1tyJHcIwh+BDwg7tAMMIw7D/ZyJoDrI8NWZ HEnFT9Zx/rg3wjV2y3ubG29U7jeIWrpj8sY/k= Message-ID: <4BE27123.6070501@gmail.com> Date: Thu, 06 May 2010 09:34:59 +0200 From: Xose Vazquez Perez User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Stefan Weinhuber CC: Heiko Carstens , Stefan Weinhuber , Horst Hummel , Stefan Haberland , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: deadline ALWAYS default for dasd devices(s390) ? References: <4BD58848.8090205@gmail.com> <20100505061620.GA2381@osiris.boeblingen.de.ibm.com> <4BE123B1.1050500@linux.vnet.ibm.com> In-Reply-To: <4BE123B1.1050500@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/05/2010 09:52 AM, Stefan Weinhuber wrote: hi, > At the time this change was made we had the problem that the > default scheduler chosen by the distributions resulted in > bad performance for DASD devices. Have you done recently new cfq vs. deadline tests, in z/VM and LPAR ? > I agree that hard coding this choice into the driver is not pretty, > but it is pragmatic. It's awful. Easier and simpler from user space: /sys/block/dasdX/queue/scheduler > Some generic mechanism for setting driver specific > defaults would be nicer, but I doubt that many other drivers would > actually benefit from such an interface. see s390-tools-1.8.4/etc/udev/rules.d/60-readahead.rules That's the way to do it. -thanks- -- «Allá muevan feroz guerra, ciegos reyes por un palmo más de tierra; que yo aquí tengo por mío cuanto abarca el mar bravío, a quien nadie impuso leyes. Y no hay playa, sea cualquiera, ni bandera de esplendor, que no sienta mi derecho y dé pecho a mi valor.»