mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@osdl.org>
To: mru@users.sourceforge.net (Måns Rullgård)
Cc: linux-kernel@vger.kernel.org
Subject: Re: Disk performance degradation
Date: Thu, 31 Jul 2003 14:15:17 -0700	[thread overview]
Message-ID: <20030731141517.0ceccc77.akpm@osdl.org> (raw)
In-Reply-To: <yw1xy8yf3xgz.fsf@users.sourceforge.net>

mru@users.sourceforge.net (Måns Rullgård) wrote:
>
> Mike Dresser <mdresser_l@windsormachine.com> writes:
> 
> > Probably for reasons like that.  For some reason, I can't set my ICH4
> > based controller(ASUS P4B533) and Quantum Fireball AS40.0 to more than
> > 255.  Kernel is 2.4.21
> 
> It appears that in 2.[56] kernels the unit for readahead is bytes,
> rather than sectors, as used in 2.4 kernels.

The ioctl which is used by

	blockdev --setra

is still in 512-byte units.

There are other backdoors such as IDE-private /proc files which can be used
to set readahead.  I'm not sure what units they use, and I don't know what
mechanism hdparm is using to diddle readahead.

Whatever it is, I suggest you ignore it and use /sbin/blockdev; it works
for all disk types.


  parent reply	other threads:[~2003-07-31 21:27 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-07-29 16:21 Voluspa
2003-07-29 16:50 ` Lou Langholtz
2003-07-30  4:17   ` Voicu Liviu
2003-07-30 21:02   ` Mike Dresser
2003-07-31  8:35     ` Måns Rullgård
2003-07-31 14:00       ` Mike Dresser
2003-07-31 21:15       ` Andrew Morton [this message]
2003-07-31 22:17         ` Bartlomiej Zolnierkiewicz
2003-07-30  8:50 ` Stefano Rivoir
2003-07-30 10:55   ` Andrew Morton
2003-07-30 16:06     ` Stefano Rivoir
2003-07-30 18:44       ` Andrew Morton
2003-07-31  0:21         ` Rahul Karnik
2003-07-31  6:59         ` Stefano Rivoir
2003-07-31  7:16           ` Andrew Morton
  -- strict thread matches above, loose matches on Subject: below --
2003-07-30 11:43 Frederick, Fabian
2003-07-29 12:00 Stefano Rivoir

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=20030731141517.0ceccc77.akpm@osdl.org \
    --to=akpm@osdl.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mru@users.sourceforge.net \
    /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
all inboxes | Powered by JetHome®