From: Andrew Morton <akpm@zip.com.au>
To: Marinos Yannikos <mjy@geizhals.at>
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 09:31:34 -0700 [thread overview]
Message-ID: <3BD6ECE6.8C9435C4@zip.com.au> (raw)
In-Reply-To: <3BD6B278.3070300@geizhals.at>
Marinos Yannikos wrote:
>
> Hi,
>
> our brand-new ICP GDT8523RZ controller with 6 disks peaks out at
> 45MB/s under 2.4.10, while with 2.2.19 it reaches 85MB/s (seq.
> read performance). It should realistically be able to reach
> at least 150-200MB/s in this configuration
Well that's pretty bad, isn't it?
Some things which it would be interesting to try out:
- Disable CONFIG_HIGHMEM in your kernel config, see
what that does.
- Try linux-2.4.13 -- 2.4.10 was a bit of a dog (this may make
a difference if the driver uese the new PCI DMA API,
but it doesn't explain why 2.2.x does so much better).
- Profile the kernel. You may enable profiling by booting
the kernel with the LILO option `profile=1'.
Then, making sure that /boot/System.map reflects the
running kernel, run this little script
#!/bin/sh
TIMEFILE=/tmp/$(basename $1).time
sudo readprofile -r
time "$@"
readprofile -v -m /boot/System.map | sort -n +2 | tail -40 | tee $TIMEFILE
echo created $TIMEFILE
With something like:
~/kern-prof.sh cp some_huge_file /dev/null
next prev parent reply other threads:[~2001-10-24 16:35 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 [this message]
2001-10-24 20:51 ` Marinos J. Yannikos
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=3BD6ECE6.8C9435C4@zip.com.au \
--to=akpm@zip.com.au \
--cc=linux-kernel@vger.kernel.org \
--cc=mjy@geizhals.at \
/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).