From: Andrew Morton <akpm@digeo.com>
To: "Justin T. Gibbs" <gibbs@scsiguy.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>,
Jens Axboe <axboe@suse.de>, Matthew Jacob <mjacob@feral.com>,
"Pedro M. Rodrigues" <pmanuel@myrealbox.com>,
Mathieu Chouquet-Stringer <mathieu@newview.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Warning - running *really* short on DMA buffers while doingfile transfers
Date: Fri, 27 Sep 2002 12:07:55 -0700 [thread overview]
Message-ID: <3D94AC8B.4AB6EB09@digeo.com> (raw)
In-Reply-To: 2543856224.1033153019@aslan.btc.adaptec.com
"Justin T. Gibbs" wrote:
>
> ...
> > The evidence is here:
> >
> > http://marc.theaimsgroup.com/?l=linux-kernel&m=103302456113997&w=1
>
> Which unfortunately characterizes only a single symptom without breaking
> it down on a transaction by transaction basis. We need to understand
> how many writes were queued by the OS to the drive between each read to
> know if the drive is actually allowing writes to pass reads or not.
>
Given that I measured a two-second read latency with four tags,
that would be about 60 megabytes of write traffic after the
read was submitted. Say, 120 requests. That's with a tag
depth of four.
Not sure how old the disk is. It's a 36G Fujitsu SCA-2. Manufactured
in 2000, perhaps??
next prev parent reply other threads:[~2002-09-27 19:02 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-26 3:27 Warning - running *really* short on DMA buffers while doing file transfers Mathieu Chouquet-Stringer
2002-09-26 6:14 ` Jens Axboe
2002-09-26 7:04 ` Pedro M. Rodrigues
2002-09-26 15:31 ` Justin T. Gibbs
2002-09-27 6:13 ` Jens Axboe
2002-09-27 6:33 ` Matthew Jacob
2002-09-27 6:36 ` Jens Axboe
2002-09-27 6:50 ` Matthew Jacob
2002-09-27 6:56 ` Jens Axboe
2002-09-27 7:18 ` Matthew Jacob
2002-09-27 7:24 ` Jens Axboe
2002-09-27 7:29 ` Matthew Jacob
2002-09-27 7:34 ` Matthew Jacob
2002-09-27 7:45 ` Jens Axboe
2002-09-27 8:37 ` Matthew Jacob
2002-09-27 10:25 ` Jens Axboe
2002-09-27 12:18 ` Matthew Jacob
2002-09-27 12:54 ` Jens Axboe
2002-09-27 13:30 ` Justin T. Gibbs
2002-09-27 14:26 ` James Bottomley
2002-09-27 14:33 ` Jens Axboe
2002-09-27 16:26 ` Justin T. Gibbs
2002-09-27 17:21 ` James Bottomley
2002-09-27 18:56 ` Justin T. Gibbs
2002-09-27 19:07 ` Andrew Morton [this message]
2002-09-27 19:16 ` Warning - running *really* short on DMA buffers while doingfile transfers Justin T. Gibbs
2002-09-27 19:36 ` Warning - running *really* short on DMA buffers while doingfiletransfers Andrew Morton
2002-09-27 19:52 ` Justin T. Gibbs
2002-09-27 21:13 ` James Bottomley
2002-09-27 21:18 ` Matthew Jacob
2002-09-27 21:23 ` James Bottomley
2002-09-27 21:29 ` Justin T. Gibbs
2002-09-27 21:32 ` Matthew Jacob
2002-09-27 22:08 ` Mike Anderson
2002-09-30 23:49 ` Doug Ledford
2002-09-27 21:28 ` Justin T. Gibbs
2002-09-28 15:52 ` James Bottomley
2002-09-28 23:25 ` Luben Tuikov
2002-09-29 2:48 ` James Bottomley
2002-09-30 8:34 ` Jens Axboe
2002-09-29 4:00 ` Justin T. Gibbs
2002-09-29 15:45 ` James Bottomley
2002-09-29 16:49 ` [ getting OT ] " Matthew Jacob
2002-09-30 19:06 ` Luben Tuikov
2002-09-30 23:54 ` Doug Ledford
2002-09-27 19:58 ` Andrew Morton
2002-09-27 20:58 ` Warning - running *really* short on DMA buffers while doing file transfers Justin T. Gibbs
2002-09-27 21:38 ` Patrick Mansfield
2002-09-27 22:08 ` Justin T. Gibbs
2002-09-27 22:28 ` Patrick Mansfield
2002-09-27 22:48 ` Justin T. Gibbs
2002-09-27 18:59 ` Warning - running *really* short on DMA buffers while doingfile transfers Andrew Morton
2002-09-27 14:30 ` Warning - running *really* short on DMA buffers while doing file transfers Jens Axboe
2002-09-27 17:19 ` Justin T. Gibbs
2002-09-27 18:29 ` Rik van Riel
2002-09-27 14:56 ` Rik van Riel
2002-09-27 15:34 ` Matthew Jacob
2002-09-27 15:37 ` Jens Axboe
2002-09-27 17:20 ` Justin T. Gibbs
2002-09-27 12:28 ` Pedro M. Rodrigues
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=3D94AC8B.4AB6EB09@digeo.com \
--to=akpm@digeo.com \
--cc=James.Bottomley@steeleye.com \
--cc=axboe@suse.de \
--cc=gibbs@scsiguy.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=mathieu@newview.com \
--cc=mjacob@feral.com \
--cc=pmanuel@myrealbox.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).