Re: Drastic Slowdown of 'fseek()' Calls From 2.4 to 2.6 -- VMM Change?

From: Hans Reiser
Date: Tue Feb 28 2006 - 13:36:17 EST


Bill Davidsen wrote:

> Hans Reiser wrote:
>
>> Andrew Morton wrote:
>>
>>> runs like a dog on 2.6's reiserfs. libc is doing a (probably) 128k
>>> read
>>> on every fseek.
>>>
>>> - There may be a libc stdio function which allows you to tune this
>>> behaviour.
>>>
>>> - libc should probably be a bit more defensive about this anyway -
>>> plainly the filesystem is being silly.
>>>
>>>
>> I really thank you for isolating the problem, but I don't see how you
>> can do other than blame glibc for this. The recommended IO size is only
>> relevant to uncached data, and glibc is using it regardless of whether
>> or not it is cached or uncached. Do I misunderstand something
>> myself here?
>
>
> I think the issue is not "blame" but what effect this behavior would
> have on things like database loads, where seek-write would be common.
> Good to get this info to users and admins.
>
Well, ok, let me phrase it as "this should be fixed in glibc". Does
anyone know who the maintainer for it is?
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