From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263022AbTDRLRu (ORCPT ); Fri, 18 Apr 2003 07:17:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263023AbTDRLRu (ORCPT ); Fri, 18 Apr 2003 07:17:50 -0400 Received: from siaag2ad.compuserve.com ([149.174.40.134]:43480 "EHLO siaag2ad.compuserve.com") by vger.kernel.org with ESMTP id S263022AbTDRLRt (ORCPT ); Fri, 18 Apr 2003 07:17:49 -0400 Date: Fri, 18 Apr 2003 07:25:46 -0400 From: Chuck Ebbert <76306.1226@compuserve.com> Subject: Re: DMA transfers in 2.5.67 To: Andrew Morton Cc: linux-kernel Message-ID: <200304180729_MC3-1-34EE-CBE8@compuserve.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > > Chuck Ebbert <76306.1226@compuserve.com> wrote: > > > > > > # mount /ext3_fs > > > # time dd if=/ext3_fs/100MiB_file of=/dev/null bs=32k > > > > > > 2.4.20aa1 : 3.3 sec (exactly what I expect to see) > > > 2.5.66 : 6.6 sec > > > > With this test 2.4 will leave a lot more unwritten dirty data in memory. > > > > You should include a `sync' in the timings. > > Well you should include the sync if you're writing to disk ;) :) All is not beer and skittles here with Andrea's kernel, though. Sometimes instead of 31MB/sec I get this with 1 sequential stream: 1 0 0 0 1232 1120 47988 0 0 14928 0 3834 7534 1 44 55 1 0 0 0 1372 1120 47848 0 0 14704 0 3778 7446 0 32 68 1 0 0 0 1464 1064 47816 0 0 14880 0 3822 7501 1 43 56 1 0 0 0 1336 1064 47944 0 0 14844 0 3813 7493 0 29 71 1 0 0 0 1432 1064 47848 0 0 14748 32 3800 7467 0 41 59 1 0 0 0 1532 1064 47748 0 0 13976 0 3596 7045 1 33 66 Pretty high context switch and interrupt rates for a PPro 200, huh? And I can't reliably reproduce it (so far...) ------ Chuck