Re: [PATCH 0/4] linux-2.6-block: deactivating pagecache for benchmarks

Dirk Henning Gerdes
2005-12-01T13:43:50Z

Probably I should have mentioned, how my benchmark should look like:

I have written a little c-program opening several files for reading and
writing.
The dentry-cache would only play a role the first time, the files are
opened. I'm not quite sure about the inode-cache.
I check if the page has buffer, and mark them as not uptodate, too. So
the buffer-cache is disabled, too.

I'm using ext2/ext3. I don't think, they use any additional caches.

But anyway: Could you explain your fake-umount idea a little more ?

Am Donnerstag, den 01.12.2005, 14:29 +0100 schrieb Arjan van de Ven:
> On Thu, 2005-12-01 at 14:17 +0100, Dirk Henning Gerdes wrote:
> > Hi Jens!
> >
> > For doing benchmarks on the I/O-Schedulers, I thought it would be very
> > useful to disable the pagecache.
>
>
> for benchmarks this is not enough though, you also need to clean the
> inode and dentry caches, as well as any filesystem specific caches
> (might be buffer cache).....
> at which point it's probably nicer to just fake a limited umount since
> that has to do all of that anyway
>
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Dirk Henning Gerdes
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