From: "Marinos J. Yannikos" <mjy@geizhals.at>
To: Andrew Morton <akpm@zip.com.au>
Cc: linux-kernel@vger.kernel.org
Subject: Re: gdth / SCSI read performance issues (2.2.19 and 2.4.10)
Date: Wed, 24 Oct 2001 22:51:02 +0200 [thread overview]
Message-ID: <3BD729B6.6030902@geizhals.at> (raw)
In-Reply-To: <3BD6B278.3070300@geizhals.at> <3BD6ECE6.8C9435C4@zip.com.au>
Andrew Morton wrote:
> Well that's pretty bad, isn't it?
We could have bought a much cheaper controller and slower disks ;-)
> - Disable CONFIG_HIGHMEM
That seems to have no effect on performance. Btw., the 64GB support in
2.4.10 seemed to be buggy ("0-order allocation failed", then the DB
crashed), so we were using the 4GB setting.
> - Try linux-2.4.13
This helped - now performance is up to par with 2.2.19 (~ 85MB/s) - thanks!
> - Profile the kernel. [...] With something like:
> ~/kern-prof.sh cp some_huge_file /dev/null
I tried this, but with
dd if=/dev/sda of=/dev/null bs=1024k count=3000
(the fs is too slow - so "cp" peaks out at 17MB/s!)
The result (last 4 lines):
c01388fc try_to_free_buffers 55 0.1511
c0128b10 file_read_actor 1179 14.0357
c01053b0 default_idle 6784 130.4615
00000000 total 8695 0.0065
Does this suggest that the kernel isn't the bottleneck?
Regards,
Marinos
--
Marinos Yannikos, CEO
Preisvergleich Internet Services AG
Franzensbrückenstraße 8/2/16, A-1020 Wien
Tel./Fax: (+431) 5811609-52/-55
next prev parent reply other threads:[~2001-10-24 20:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-10-24 12:22 gdth / SCSI read performance issues (2.2.19 and 2.4.10) Marinos Yannikos
2001-10-24 16:31 ` Andrew Morton
2001-10-24 20:51 ` Marinos J. Yannikos [this message]
2001-10-24 21:28 ` Andrew Morton
2001-10-24 22:55 ` Marinos J. Yannikos
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=3BD729B6.6030902@geizhals.at \
--to=mjy@geizhals.at \
--cc=akpm@zip.com.au \
--cc=linux-kernel@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 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).