From: Stephen Lord <lord@sgi.com>
To: Jens Axboe <axboe@suse.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: SCSI I/O performance problems when CONFIG_HIGHIO is off
Date: 18 Nov 2002 08:05:13 -0600 [thread overview]
Message-ID: <1037628312.1680.5.camel@laptop.americas.sgi.com> (raw)
In-Reply-To: <20021118120531.GC839@suse.de>
On Mon, 2002-11-18 at 06:05, Jens Axboe wrote:
>
> Steve,
>
> Something isn't quite making sense. If we go over every single instance
> of checking ->highmem_io, they all look sane (ie checking on non-highmem
> setup must yield 0). So that part looks good.
>
> However, I think a typo snuck in there, in exactly the spot you pasted
> above. Could you try 2.4.20-rc2 with this patch applied?
>
> ===== drivers/scsi/scsi_merge.c 1.9 vs edited =====
> --- 1.9/drivers/scsi/scsi_merge.c Mon Sep 16 09:25:10 2002
> +++ edited/drivers/scsi/scsi_merge.c Mon Nov 18 13:04:41 2002
> @@ -835,7 +835,7 @@
> * case.
> */
> if (count == 1 && !SCpnt->host->highmem_io) {
> - this_count = req->current_nr_sectors;
> + this_count = req->nr_sectors;
> goto single_segment;
> }
That looks like it does it, performance is pretty much what I was
getting with HIGHIO on.
Thanks
Steve
--
Stephen Lord <lord@sgi.com>
next prev parent reply other threads:[~2002-11-18 14:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-15 20:31 Steve Lord
2002-11-16 8:18 ` Jens Axboe
2002-11-18 12:05 ` Jens Axboe
2002-11-18 14:05 ` Stephen Lord [this message]
2002-11-18 14:12 ` Jens Axboe
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