All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@digeo.com>
To: James Bottomley <James.Bottomley@steeleye.com>
Cc: linux-scsi@vger.kernel.org, Jens Axboe <axboe@suse.de>
Subject: Re: Possible explanation for SCSI benchmark problems in 2.5
Date: Sun, 29 Sep 2002 13:53:56 -0700	[thread overview]
Message-ID: <3D976864.65C82D7B@digeo.com> (raw)
In-Reply-To: 200209292048.g8TKmN424799@localhost.localdomain

James Bottomley wrote:
> 
> Hi All,
> 
> While looking at other code (OK, how to get the MCA drivers not to use bounce
> buffers...)  I discovered that the way scsi_scan.c calls
> scsi_initialize_merge_fn() guarantees (on an x86) that the
> blk_queue_bounce_limit is always called with BLK_BOUNCE_HIGH.  This will
> probably hurt benchmarks on machines with 1Gb or more of memory.
> 
> The problem is that scsi_initialize_merge_fn() checks sdev->type, but this is
> always -1 in scsi_alloc_sdev, and thus it never uses the pci dma mask for disk
> devices.
> 
> The attached patch moves the initialisation to after sdev->type has the
> correct value.
> 

argh, sorry.  I've had such a patch in my tree for ages, and
I do all testing with it in place.

But high-IO is bust for IDE as well at present, so at least
we're being fair ;)

  reply	other threads:[~2002-09-29 20:53 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-09-29 20:48 Possible explanation for SCSI benchmark problems in 2.5 James Bottomley
2002-09-29 20:53 ` Andrew Morton [this message]
2002-09-30  7:30   ` Jens Axboe
2002-09-30  7:46     ` Andrew Morton
2002-09-30  7:47       ` Jens Axboe
2002-09-29 21:32 ` Mike Anderson
2002-09-30  3:40   ` James Bottomley
2002-09-30  6:15     ` Kai Makisara
2002-09-30  7:32   ` Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=3D976864.65C82D7B@digeo.com \
    --to=akpm@digeo.com \
    --cc=James.Bottomley@steeleye.com \
    --cc=axboe@suse.de \
    --cc=linux-scsi@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.