Re: [PATCH 1/2] ext4: Calculate and verify inode checksums

From: Joel Becker
Date: Fri Apr 08 2011 - 14:50:37 EST

On Thu, Apr 07, 2011 at 10:10:52AM -0700, Sunil Mushran wrote:
> On 04/07/2011 09:40 AM, Darrick J. Wong wrote:
> >That said, I haven't really quantified the performance impact of this naive
> >approach yet, so I wonder -- did you see a similar scenario with ocfs2, and
> >what kind of performance increase did you get by adapting the code to use the
> >jbd2 trigger? If there's potentially a large increase, it would be interesting
> >to apply the same conversion to the group descriptor checksumming code too.
> Joel Becker may remember the overhead. He wrote the patch. That said we have few
> differences. ocfs2 has larger (blocksized) inodes. Also, it computes ECC. The code
> is in fs/ocfs2/blockcheck.c.

ocfs2 does the journal access/journal dirty cycle a lot more
than extN. I think you'd want to generate your own numbers.



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as distinguished from the Liberal, who wishes to replace them
with others."
- Ambrose Bierce, The Devil's Dictionary
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