Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755629AbXERGex (ORCPT ); Fri, 18 May 2007 02:34:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753940AbXERGeq (ORCPT ); Fri, 18 May 2007 02:34:46 -0400 Received: from mailer.gwdg.de ([134.76.10.26]:44335 "EHLO mailer.gwdg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752893AbXERGeq (ORCPT ); Fri, 18 May 2007 02:34:46 -0400 Date: Fri, 18 May 2007 08:33:47 +0200 (MEST) From: Jan Engelhardt To: DervishD cc: Stefan Richter , linux-kernel@vger.kernel.org Subject: Re: usb-storage nice value In-Reply-To: <20070518061512.GA32730@DervishD> Message-ID: References: <20070517100308.GA14667@DervishD> <464CB2B3.50506@s5r6.in-berlin.de> <20070518061512.GA32730@DervishD> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Report: Content analysis: 0.0 points, 6.0 required _SUMMARY_ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1845 Lines: 55 On May 18 2007 08:15, DervishD wrote: >Date: Fri, 18 May 2007 08:15:12 +0200 >From: DervishD >To: Stefan Richter >Cc: linux-kernel@vger.kernel.org >Subject: Re: usb-storage nice value Try ionice. >> DervishD wrote: >> > I'm having problems when reading/writing to external USB harddisks: >> > my *internal* harddisk stalls from time to time, so watching a movie >> > while copying data is a PITA (well, if the movie is bad, the leaps help >> > a bit...). >> >> If the internal harddisk is source or target of these copy operations... > > Not... > >> ... >> > is there any way of modifying the pdflush behaviour so >> > large buffered writes are less "agressive" and doesn't block apps which >> > are just reading? >> >> ...then switching to another IO scheduler might perhaps help. >> >> # cat /sys/block/hda/queue/scheduler >> >> # echo deadline > /sys/block/hda/queue/scheduler > Or try echo 10 >/proc/sys/kernel/dirty_ratio > That's another thing I wanted to test, but I'm already using >"deadline" scheduler. How about changing "read_ahead_kb" to a much >higher value so there's plenty of data buffered? The problem seems to >be, according to Alan Cox, that my VIA mobo fills completely the PCI bus >when doing IO bursts, so I can take advantage of that "bug" and fill the >bus when reading. > > My only doubt is if it will affect performance negatively in other >usage patterns (e.g. while writing CD's, since the hard disk will take >the bus on each read operation, and will read more than the current 128 >kB). Jan -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/