Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 29 Aug 2002 16:51:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 29 Aug 2002 16:51:16 -0400 Received: from e21.nc.us.ibm.com ([32.97.136.227]:13471 "EHLO e21.nc.us.ibm.com") by vger.kernel.org with ESMTP id ; Thu, 29 Aug 2002 16:51:14 -0400 From: Badari Pulavarty Message-Id: <200208292055.g7TKte224951@eng2.beaverton.ibm.com> Subject: Re: 2.5.32 IO performance issues To: akpm@zip.com.au (Andrew Morton) Date: Thu, 29 Aug 2002 13:55:40 -0700 (PDT) Cc: pbadari@us.ibm.com (Badari Pulavarty), linux-kernel@vger.kernel.org, gerrit@us.ibm.com (Gerrit Huizenga), hjt@us.ibm.com (Hans-J Tannenberger), janetmor@us.ibm.com (Janet Morgan), andmike@us.ibm.com (Mike Anderson), mjbligh@us.ibm.com (Martin Bligh) In-Reply-To: <3D6E6B64.66203783@zip.com.au> from "Andrew Morton" at Aug 29, 2002 10:43:48 AM PST X-Mailer: ELM [version 2.5 PL3] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3095 Lines: 65 > > Badari Pulavarty wrote: > > > > Hi, > > > > I am having severe IO performance problems with 2.5.32 (2.5.31 works fine). > > I was wondering what caused this. > > > > As you can see, IO rate went from > > > > 384MB/sec with 6% CPU utilization on 2.5.31 > > to > > 120MB/sec with 19% CPU utilization on 2.5.32 > > > > ... > > 151712 default_idle 2370.5000 > > 21622 __scsi_end_request 122.8523 > > block-highmem is bust for scsi. (aic7xxx at least). Does > http://www.zip.com.au/~akpm/linux/patches/2.5/2.5.32/2.5.32-mm2/broken-out/scsi_hack.patch > fix it? Hmm !! This patch fixed it. I remember you gave me this patch for 2.5.31. But 2.5.31 was doing fine without it. But 2.5.32 seem to need it. procs memory swap io system cpu r b w swpd free buff cache si so bi bo in cs us sy id 1 38 0 0 3811160 0 23532 0 0 384461 0 3981 6346 0 5 95 0 39 0 0 3811152 0 23532 0 0 384499 0 3967 6354 0 5 95 0 39 0 0 3811148 0 23532 0 0 384154 0 3974 6341 0 5 95 0 39 0 0 3811144 0 23532 0 0 384013 0 3964 6344 0 5 95 0 39 0 0 3811204 0 23532 0 0 384154 0 3966 6357 0 5 95 0 39 0 0 3811176 0 23532 0 0 384256 0 3973 6341 0 5 95 0 39 0 0 3811168 0 23532 0 0 384320 0 3969 6329 0 5 95 0 39 0 0 3811152 0 23532 0 0 384294 0 3980 6335 0 5 95 Here is the profile output with this patch: # readprofile | sort -nr +2 221145 default_idle 3455.3906 3163 do_softirq 16.4740 1489 __scsi_end_request 8.4602 1696 scsi_dispatch_cmd 2.7895 371 dio_bio_complete 2.1080 509 blk_rq_map_sg 1.3255 198 dio_await_one 1.2375 57 dio_prep_bio 1.1875 56 bio_put 1.1667 71 __generic_copy_to_user 1.1094 630 do_direct_IO 0.9157 42 __wake_up 0.8750 297 __set_page_dirty_buffers 0.8438 622 schedule 0.6942 629 __make_request 0.5460 402 get_user_pages 0.5346 17 scsi_sense_valid 0.5312 42 bio_destructor 0.5250 198 bio_alloc 0.4760 32 dio_get_page 0.4000 - 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/