Re: Improving prep_buildtree used in VPATH builds

Excerpts from Gurjeet Singh's message of dom sep 26 22:15:59 -0400 2010:

> Currently I am seeing a performance improvement of this script by only about
> 500 ms; say 11.8 seconds vs. 11.3 secs. But I remember distinctly that
> yesterday I was able to see an improvement of 11% on the same virtual
> machine, averaged on multiple runs; 42 sec vs 37 sec. It might be the case
> that the host OS or my Linux virtual machine were loaded at that time and
> the filesystem could not cache enough inodes.

Hmm.  On my otherwise idle desktop machine, I can't measure a difference.
But this machine has enough RAM for inode cache.

With patch:

real    0m3.092s
user    0m0.900s
sys     0m2.220s

real    0m3.116s
user    0m0.928s
sys     0m2.176s

real    0m3.128s
user    0m1.040s
sys     0m2.108s

Without patch:

real    0m3.109s
user    0m0.852s
sys     0m2.180s

real    0m3.101s
user    0m0.884s
sys     0m2.264s

real    0m3.121s
user    0m0.968s
sys     0m2.140s

> Seems like it would improve performance in general, but more so under load
> conditions when you actually need it. I am not sure if -depth option is
> supported by all incarnations of 'find'.

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Álvaro Herrera <alvherre@commandprompt.com>
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