From: Jens Axboe <axboe@suse.de>
To: "Paul A. Sumner" <paul@zanfx.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: High write latency, iowait, slow writes 2.6.9
Date: Thu, 13 Jan 2005 09:56:33 +0100 [thread overview]
Message-ID: <20050113085633.GE2815@suse.de> (raw)
In-Reply-To: <41E61C68.10801@zanfx.com>
On Wed, Jan 12 2005, Paul A. Sumner wrote:
> Thanks... I've tried the as, deadline and cfq schedulers. Deadline is
> giving me the best results. I've also tried tweaking the stuff in
> /sys/block/sda/queue/iosched/.
>
> For lack of a better way of describing it, it seems like something is
> thrashing.
I you have time, I would like you to try current BK with this patch:
http://www.kernel.org/pub/linux/kernel/people/axboe/patches/v2.6/2.6.11-rc1/cfq-time-slices-20.gz
You should enable CONFIG_IOPRIO_WRITE, it is in the io scheduler config
section, if you do a make oldconfig it should pop up for you. Boot with
elevator=cfq to select cfq.
A simple profile of the bad period would also be nice, along with
vmstat 1 info from that period. If you boot with profile=2, do:
# readprofile -r
# run bad workload
# readprofile | sort -nr +2 > result_file
And send that along with the logged vmstat 1 from that same period.
Oh, and lastly, remember to CC people on lkml when you respond, thanks.
--
Jens Axboe
next prev parent reply other threads:[~2005-01-13 8:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-12 5:54 High write latency, iowait, slow writes 2.6.9 Paul A. Sumner
2005-01-12 21:20 ` Miquel van Smoorenburg
2005-01-13 6:59 ` Paul A. Sumner
2005-01-13 8:56 ` Jens Axboe [this message]
2005-01-13 19:01 ` Paul A. Sumner
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=20050113085633.GE2815@suse.de \
--to=axboe@suse.de \
--cc=linux-kernel@vger.kernel.org \
--cc=paul@zanfx.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 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.