invalidate/drop filesystem caches & io buffers

invalidate/drop filesystem caches & io buffers

[Yakov Lerner]

I'd like to invalidate/free the filesystem caches and io buffer cache
How can I do this when I can't unmount the filesystem (and w/o reboot) ?

(I run filesystem I/O test that needs to  start from fresh  cache &
buffer state -- as emty as possible, like right after mount/boot).

I tried  'mount -o remount' but it didn't make any difference
on the timing. Apparently 'mount -o remount' did not invalidate
cases/buffers ? ( The difference between fresh run vs non-fresh
run timing is x5 times ).

Thanks
Yakov

Re: invalidate/drop filesystem caches & io buffers

[Arjan van de Ven]

On Wed, 2006-11-08 at 14:53 +0200, Yakov Lerner wrote:
> I'd like to invalidate/free the filesystem caches and io buffer cache
> How can I do this when I can't unmount the filesystem (and w/o reboot) ?


echo 1 > /proc/sys/vm/drop_caches

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Re: invalidate/drop filesystem caches & io buffers

[Hesse, Christian]

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On Wednesday 08 November 2006 13:53, Yakov Lerner wrote:
> I'd like to invalidate/free the filesystem caches and io buffer cache
> How can I do this when I can't unmount the filesystem (and w/o reboot) ?
>
> (I run filesystem I/O test that needs to  start from fresh  cache &
> buffer state -- as emty as possible, like right after mount/boot).
>
> I tried  'mount -o remount' but it didn't make any difference
> on the timing. Apparently 'mount -o remount' did not invalidate
> cases/buffers ? ( The difference between fresh run vs non-fresh
> run timing is x5 times ).

You can do

echo 3 > /proc/sys/vm/drop_caches

Take a look at filesystems/proc.txt for details.
-- 
Regards,
Christian

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