[Patches] [ python-Patches-430948 ] Performance improvement for profiler

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Patches item #430948, was updated on 2001-06-06 22:29
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Category: library
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Fred L. Drake, Jr. (fdrake)
>Assigned to: Tim Peters (tim_one)
Summary: Performance improvement for profiler

Initial Comment:
This patch adds a bit of complexity to
Profile.__init__() in an effort to reduce the overhead
of the profiler.  The essential piece of the puzzle is
that the general Profile.get_time() method is replaced
with a function which does only as much as is needed
for the underlying timer.  For example, if time.clock()
is available, it can become a PyCFunction instead of a
bound method, requires only 1 dict lookup to execute
instead of the 11 it takes to execute get_time()
without this patch.

Also removes a couple of duplicate imports from the "if
__name__ == ..." section.


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>Comment By: Fred L. Drake, Jr. (fdrake)
Date: 2001-06-07 14:37

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I've attached a revised patch with the suggested changes,
plus a few more.  This is more agressive about avoiding
dictionary lookups, and the dispatch table no longer
contains bound methods -- using plain functions with self
passed as an explicit argument is faster as it avoids more
of Python's call machinery, and avoids circular references.

This patch also attempts not to add any breakage to the
OldProfile and HotProfile classes.

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Comment By: Tim Peters (tim_one)
Date: 2001-06-07 12:39

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Fine by me (and good idea!).  I'd rather see get_time_mac 
be a module-level function _get_time_mac, get_time_timer a 
module-level _get_time_timer (or, better, _get_time_list), 
and get_time_times a module-level function _get_time_times; 
and in the last case without the needless expense of reduce
():

.def _get_time_times(times=os.times):
.    t = times()
.    return t[0] + t[1]

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Comment By: Fred L. Drake, Jr. (fdrake)
Date: 2001-06-06 22:30

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I should note that this works with both 2.1.1 and 2.2,
though this is not a bugfix.

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