Date: Mon, 26 Apr 2004 13:42:17 -0600
From: Bruce Guenter <lists-linux-xfs@bruce-guenter.dyndns.org>
To: linux-xfs@oss.sgi.com
Subject: Re: Speeding up XFS
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On Mon, Apr 26, 2004 at 01:52:47PM -0500, Steve Lord wrote:
> The very wierd part is the slowdown you see with an external journal
> in the last case. I can see no reason why an external vs an internal
> journal would be different except for the possibility that there
> is some form of interaction with queue unplugging in the elevators
> between devices. It might be worth trying Linus's latest bitkeeper
> tree (2.6.6-rc2) which has per device queue unplugging and see
> if that makes a difference.

I am currently re-running some of the tests with 2.6.6-rc2-mm2.  I'll
re-run with XFS too and post my results.

> Your website also comments on xfs read performance slowing down
> when there are a large number of files present. Can you define
> 'a large number of files'.

Large is perhaps an exaggeration.  On the order of 100,000 files
(averaging roughly one per directory).

> I attached a perl script. If you run this once a second and capture the
> output when things are going bad it might tell us a few things.

I'll do that.
--=20
Bruce Guenter <bruceg@em.ca> http://em.ca/~bruceg/ http://untroubled.org/
OpenPGP key: 699980E8 / D0B7 C8DD 365D A395 29DA  2E2A E96F B2DC 6999 80E8

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