Re: Clearing the I/O caches? (for benchmark tests)

Stephen C. Tweedie (sct@redhat.com)
Thu, 15 Jul 1999 12:50:56 +0100 (BST)


Hi,

On Wed, 14 Jul 1999 22:06:22 +0200, Jamie Lokier
<lkd@tantalophile.demon.co.uk> said:

> I use the following script to flush I/O caches for benchmarks.
> Does it suffer from the same problem?

Yes, a remount doesn't flush the internal ext2 bitmap caches. A remount
doesn't flush _anything_ from the buffer cache: it only ever flushes the
unpinned part of the inode cache. The hdparm -f skips over any buffers
which are still in active use (ie. which have a non-zero bh->b_count).

--Stephen

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