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From: jon ross <jonross@gmail.com>
To: linux-kernel@vger.kernel.org
Subject: VM disk cache behavior.
Date: Tue, 8 Feb 2005 12:06:14 -0500	[thread overview]
Message-ID: <e130a7170502080906596561d7@mail.gmail.com> (raw)

I have an app with a small fixed memory footprint that does a lot of
random reads from a large file. I thought if I added more memory to
the machine the VM would do more caching of the disk, but added memory
does not seem to make any difference. I played with some of the params
in /proc/sys/vm and none of them seem to have any effect.

I tired both a 2.4.20 & 2.6.10 kernels with no difference.

The machine is a Dell 2560. I tired memory configs of 512M, 1G, 4G and
the average read-times do not change.

Do I need to set/compile anything to allow the VM to use the memory?
If is was a way to tell how much memory the VM is using for a drive
cache I could at least tell if my kernel is miss-configured or my app
sucks.

Thanks,

-Jon

             reply	other threads:[~2005-02-08 17:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-02-08 17:06 jon ross [this message]
2005-02-08 17:18 ` VM disk cache behavior Robert Love
2005-02-08 20:07 ` Chris Wedgwood
2005-02-09  0:37 ` Andy Isaacson
2005-02-09  5:03   ` Kevin Puetz

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