From: Mark Lord <lkml@rtr.ca>
To: Marr <marr@flex.com>
Cc: Linda Walsh <lkml@tlinx.org>, Bill Davidsen <davidsen@tmr.com>,
linux-kernel@vger.kernel.org, reiserfs-dev@namesys.com,
Andrew Morton <akpm@osdl.org>
Subject: Re: Readahead value 128K? (was Re: Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change?)
Date: Sun, 12 Mar 2006 17:15:06 -0500 [thread overview]
Message-ID: <44149D6A.7080005@rtr.ca> (raw)
In-Reply-To: <200603121653.30288.marr@flex.com>
Marr wrote:
>
> I tried turning 'readahead' off entirely ('hdparm -A0 /dev/hda') and, although
No, that should be "hdparm -a0 /dev/hda" (lowercase "-a").
And the same "-a" for all of your other test variants.
If you did it all with "-A", then the results are invalid,
and need to be redone.
The hdparm manpage explains this, but in a nutshell, "-A" is the
low-level drive firmware "look-ahead" mechanism, whereas "-a" is
the Linux kernel "read-ahead" scheme.
In general, most uppercase hdparm flags are drive *firmware* settings.
Cheers
next prev parent reply other threads:[~2006-03-12 22:15 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-24 20:22 Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change? Marr
2006-02-25 5:16 ` Andrew Morton
2006-02-26 13:07 ` Ingo Oeser
2006-02-26 13:50 ` Nick Piggin
2006-02-26 14:11 ` Arjan van de Ven
2006-02-27 20:52 ` Hans Reiser
2006-02-28 0:34 ` Nick Piggin
2006-02-28 18:42 ` Hans Reiser
2006-02-28 18:51 ` Hans Reiser
2006-02-27 20:24 ` Marr
2006-02-27 21:53 ` Hans Reiser
2006-02-28 0:03 ` Bill Davidsen
2006-02-28 18:38 ` Hans Reiser
2006-03-05 23:02 ` Readahead value 128K? (was Re: Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change?) Linda Walsh
2006-03-07 19:53 ` Marr
2006-03-07 21:15 ` Linda Walsh
2006-03-12 21:53 ` Marr
2006-03-12 22:15 ` Mark Lord [this message]
2006-03-13 4:36 ` Marr
2006-03-13 14:41 ` Mark Lord
2006-03-13 18:15 ` Hans Reiser
2006-03-13 20:00 ` Marr
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