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Re: [Gnu-arch-users] ANNOUNCEMENT -- "timestamps" optimization
From: |
Tom Lord |
Subject: |
Re: [Gnu-arch-users] ANNOUNCEMENT -- "timestamps" optimization |
Date: |
Sat, 13 Sep 2003 17:35:18 -0700 (PDT) |
> From: Jason McCarty <address@hidden>
> I did a little speed testing on Linux 2.4 (ext3 fs), with patch-160 and
> patch-162. Times reported are total time (including IO/system time).
To be clear: you mean that you tested on a 2.4 platform using the tla
tree as your test case, right?
> User time was 2.7-2.8s on every run, so it looks like tree-traversal
> costs trump file-comparing costs, regardless of how many files are
> compared.
For a tla-sized tree, that's not too surprising. If you're testing
against a much larger tree, that'd be surprising.
> So the real effect of the inode-signature optimization is to
> reduce kernel cache usage, rather than reducing cpu time
> significantly.
That's right. And for large trees (that press up against or past the
cache size) that also means less disk i/o, which has been the apparent
bottleneck on kernel-sized trees.
Thanks for the results,
-t
Re: [Gnu-arch-users] ANNOUNCEMENT -- "timestamps" optimization, Florian Weimer, 2003/09/14