Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752142AbZJKIXr (ORCPT ); Sun, 11 Oct 2009 04:23:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751795AbZJKIXr (ORCPT ); Sun, 11 Oct 2009 04:23:47 -0400 Received: from mail-yx0-f188.google.com ([209.85.210.188]:54278 "EHLO mail-yx0-f188.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751787AbZJKIXp (ORCPT ); Sun, 11 Oct 2009 04:23:45 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=wJY9/pRGdDqvA/PTAeRnNAwuOsgqCvp+HG1lmGVo/7ZD/rk/cciMlOw9yXvD98QoD4 mhI+YsrgIvcPEwZxARwtRufgX4Q1z+B13mzcgc9FSS0lhnkTGuYBcbP0Hl8NJNDFmKs+ MVTph+74bOjZ6sZTQS+ra5WO1FEWqbi+1lGi0= MIME-Version: 1.0 In-Reply-To: <1255168333.25078.82.camel@ymzhang> References: <1255153724.25078.68.camel@ymzhang> <20091010080117.GN9228@kernel.dk> <1255168333.25078.82.camel@ymzhang> Date: Sun, 11 Oct 2009 10:23:09 +0200 Message-ID: <4e5e476b0910110123s54debc6as435c9cc0d5e8340c@mail.gmail.com> Subject: Re: fio rand read/write regression with 2.6.32-rc3 From: Corrado Zoccolo To: "Zhang, Yanmin" Cc: Jens Axboe , LKML , Linus Torvalds Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1678 Lines: 41 On Sat, Oct 10, 2009 at 11:52 AM, Zhang, Yanmin wrote: > On Sat, 2009-10-10 at 10:01 +0200, Jens Axboe wrote: >> On Sat, Oct 10 2009, Zhang, Yanmin wrote: >> > Comparing with 2.6.23-rc1's result, fio rand read write has regression >> > on my 2*4 core stoakley machine (8GB memory) with a JBOD of 12 disks. >> > >> > Every disk has 8 1-GB files. Start 8 sub-processes per disk and every >> > process random chooses a file on the disk to do 36 times of file read or >> > write on the file and then choose another file. >> > >> > >> > fio_mmap_rand_read_4k regresion is about 35%. >> >> Heh, I seem to recollect I told Linus that this would cost is 30-40% >> performance. So not totally crazy. >> >> So yes, this isn't hugely unexpected. If you send me your fio job files, >> I'll try and see what I can do about it. > See the attachment. > Hi Yanmin, the fio test you sent just performs random read, no write seems involved here. I suspect that you should be able to observe the same regression if you just run on a single disk. Can you confirm? Is your disk a SATA2 rotational disk with NCQ? Thanks, Corrado -- __________________________________________________________________________ dott. Corrado Zoccolo mailto:czoccolo@gmail.com PhD - Department of Computer Science - University of Pisa, Italy -------------------------------------------------------------------------- -- 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/