Does cProfile include IO wait time?

Matthew Wilson matt at tplus1.com
Sun Jul 5 02:03:38 CEST 2009


I have a command-line script that loads about 100 yaml files.  It takes
2 or 3 seconds.  I profiled my code and I'm using pstats to find what is
the bottleneck.

Here's the top 10 functions, sorted by internal time:

    In [5]: _3.sort_stats('time').print_stats(10)
    Sat Jul  4 13:25:40 2009    pitz_prof

             756872 function calls (739759 primitive calls) in 8.621 CPU seconds

       Ordered by: internal time
       List reduced from 1700 to 10 due to restriction <10>

       ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        15153    0.446    0.000    0.503    0.000 build/bdist.linux-i686/egg/yaml/reader.py:134(forward)
        30530    0.424    0.000    0.842    0.000 build/bdist.linux-i686/egg/yaml/scanner.py:142(need_more_tokens)
        98037    0.423    0.000    0.423    0.000 build/bdist.linux-i686/egg/yaml/reader.py:122(peek)
         1955    0.415    0.000    1.265    0.001 build/bdist.linux-i686/egg/yaml/scanner.py:1275(scan_plain)
        69935    0.381    0.000    0.381    0.000 {isinstance}
        18901    0.329    0.000    3.908    0.000 build/bdist.linux-i686/egg/yaml/scanner.py:113(check_token)
         5414    0.277    0.000    0.794    0.000 /home/matt/projects/pitz/pitz/__init__.py:34(f)
        30935    0.258    0.000    0.364    0.000 build/bdist.linux-i686/egg/yaml/scanner.py:276(stale_possible_simple_keys)
        18945    0.192    0.000    0.314    0.000 /usr/local/lib/python2.6/uuid.py:180(__cmp__)
         2368    0.172    0.000    1.345    0.001 build/bdist.linux-i686/egg/yaml/parser.py:268(parse_node)

I expected to see a bunch of my IO file-reading code in there, but I don't.  So
this makes me think that the profiler uses CPU time, not
clock-on-the-wall time.

I'm not an expert on python profiling, and the docs seem sparse.  Can I
rule out IO as the bottleneck here?  How do I see the IO consequences?

TIA

Matt



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