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From: Phillip Susi <psusi@cfl.rr.com>
To: "Magnus Naeslund(k)" <mag@kite.se>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.6 tmpfs/swap performance oddity
Date: Wed, 06 Dec 2006 15:51:34 -0500	[thread overview]
Message-ID: <45772D56.5020600@cfl.rr.com> (raw)
In-Reply-To: <457706CB.20802@kite.se>

Magnus Naeslund(k) wrote:
> But tmpfs seems to get really slow when it has to swap out stuff from
> tmp to a 80 gb swap partition, much slower than just writing a file
> to the ext3 fs. Maybe this is a known thing, and easily tuned, but
> I've not seen any solutions when googling around.

This is a SWAG ( Silly Wild Ass Guess ), but maybe tmpfs isn't mapping 
the files sequentially in ram, or is otherwise doing something to 
prevent proper swap clustering and read ahead?

> Somehow I think I'm missing something here, maybe we're not supposed
> to use tmpfs in this way at all? What more information can I supply
> to narrow down the problem? Is there any secret knobs that I can use
> to tune swap performance?

You aren't supposed to be using tmpfs in this way at all ;)

tmpfs is meant to hold small files that will only exist for a short 
time, or do not need to persist after a reboot.  Keep your big data 
files on a normal filesystem, and let the kernel worry about caching the 
most frequently accessed parts.


  reply	other threads:[~2006-12-06 20:51 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-06 18:07 2.6 tmpfs/swap performance oddity Magnus Naeslund(k)
2006-12-06 20:51 ` Phillip Susi [this message]
  -- strict thread matches above, loose matches on Subject: below --
2006-12-08  4:02 Chuck Ebbert

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