Re: [Monotone-devel] Performance accounting and testing patch

[Matthew Gregan]

At 2005-08-09T18:38:10-0700, Eric Anderson wrote:
> Summary: The attached patch adds in memory usage, copys and malloc
> accounting to monotone, and a repeatable performance test for
> evaulating CPU usage, memory usage, copies, and mallocs. Sample output
> is shown at the bottom after the detailed discussion.

Thanks, it's useful to have people looking at monotone's current
performance in a constructive fashion.

I don't think that the specific performance accounting code in the patch
needs to be included in monotone proper.  I'm not sure if you're
proposing that it should be, or if you're just making the patch
available for others who want to look at this aspect of monotone's
performance.

To extract the same sort of statistics that you're recording right now
without requiring a patch on top of monotone, I'd look at putting your
stats collection code into a interposable shared library using the usual
RTLD_NEXT/LD_PRELOAD tricks.  The /proc/<pid>/statm part of the patch
could be move into a thin 'launcher' tool that would behave in much the
same way that /usr/bin/time works now.

If you want to look at monotone's heap usage in more depth, take a look
at Valgrind (specifically massif, the heap profiler).  It will allow you
to record and examine the call-stacks of the worst offenders.  For
general profiling, a recent version of oprofile with a recent 2.6 Linux
kernel is a good start.

(Minor nit pick: the two files you added should go in scripts/, not
tests/.  The latter is the domain of autotest scriptlets.)

Cheers,
-mjg
-- 
Matthew Gregan                     |/
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