Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753629AbXFWRws (ORCPT ); Sat, 23 Jun 2007 13:52:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755871AbXFWRwh (ORCPT ); Sat, 23 Jun 2007 13:52:37 -0400 Received: from ug-out-1314.google.com ([66.249.92.175]:28896 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191AbXFWRwf (ORCPT ); Sat, 23 Jun 2007 13:52:35 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:from:to:subject:date:user-agent:cc:references:in-reply-to:mime-version:content-disposition:message-id:content-type:content-transfer-encoding; b=Elr68wzNsxP/1DHilFEaHMkqNlY1qje6T8maYNdMz1MPIFuFeuRLXSd1lIyV7ktWgW4qlk6Sp2Txmc8aQaemyzUrIUJb+qsswtD/lGV+4WWyGUBSNar/F0lOCy88xNNfX/sw5KtQs9BSVBuRJoefXf6+KOHmcukWGRgPUBUnXjQ= From: Bartlomiej Zolnierkiewicz To: Carlo Wood Subject: Re: SATA RAID5 speed drop of 100 MB/s Date: Sat, 23 Jun 2007 19:30:57 +0200 User-Agent: KMail/1.9.6 Cc: Jeff Garzik , Tejun Heo , Manoj Kasichainula , linux-kernel@vger.kernel.org, IDE/ATA development list References: <20070620224847.GA5488@alinoe.com> <467CC5C5.6040201@garzik.org> <20070623125316.GB26672@alinoe.com> In-Reply-To: <20070623125316.GB26672@alinoe.com> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200706231930.57688.bzolnier@gmail.com> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1338 Lines: 30 Hi, On Saturday 23 June 2007, Carlo Wood wrote: > PS I'd like to do extensive testing with Bonnie++ to tune everything > there is to tune. But bonnie likes to write/read files TWICE the amount > of RAM I have. It therefore takes a LOT of time to run one test. Do you > happen to know how I can limit the amount of RAM that the linux kernel > sees to, say 500 MB? That should be enough to run in Single User mode > but allow me to run the tests MUCH faster. (I have dual channel, four > DIMM's of 1 GB each -- 2 GB per Core 2 die. Hopefully the fact that > I have dual channel isn't going to be a problem when limiting the ram > that the kernel sees.) "mem=" kernel parameter limits amount of memory seen by kernel (more info in Documentation/kernel-parameters.txt) You can also limit amount of RAM detected by bonnie++ by using -r parameter but please remember that this will make bonnie++ benchmark combined kernel I/O buffering + filesystem + hard disk performance instead of just filesystem + hard disk performance (as it can happen that some / all data won't ever hit the disk). Bart - 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/