From: Hans Reiser <reiser@namesys.com>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ingo Oeser <ioe-lkml@rameria.de>,
linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>,
Marr <marr@flex.com>,
reiserfs-dev@namesys.com
Subject: Re: Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change?
Date: Mon, 27 Feb 2006 12:52:00 -0800 [thread overview]
Message-ID: <44036670.7060204@namesys.com> (raw)
In-Reply-To: <4401B233.7050308@yahoo.com.au>
Sounds like the real problem is that glibc is doing filesystem
optimizations without making them conditional on the filesystem type.
Does anyone know the email address of the glibc guy so we can ask him
not to do that?
My entry for the ugliest thought of the day: I wonder if the kernel can
test the glibc version and.....
Hans
Nick Piggin wrote:
>
> Actually glibc tries to turn this pre-read off if the seek is to a page
> aligned offset, presumably to handle this case. However a big write
> would only have to RMW the first and last partial pages, so pre-reading
> 128KB in this case is wrong.
>
> And I would also say a 4K read is wrong as well, because a big read will
> be less efficient due to the extra syscall and small IO.
>
next prev parent reply other threads:[~2006-02-27 20:52 UTC|newest]
Thread overview: 23+ 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 [this message]
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
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
[not found] <5JRJO-6Al-7@gated-at.bofh.it>
2006-02-24 23:31 ` Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change? Robert Hancock
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