| 1 | from __future__ import print_function
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| 2 | """
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| 3 | pytrace.py
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| 4 | """
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| 5 |
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| 6 | import cStringIO
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| 7 | import os
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| 8 | #import struct
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| 9 | import sys
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| 10 |
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| 11 | # TODO: Two kinds of tracing?
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| 12 | # - FullTracer -> Chrome trace?
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| 13 | # - ReservoirSamplingTracer() -- flame graph that is deterministic?
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| 14 |
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| 15 | # TODO: Check this in but just go ahead and fix wild.sh instead.
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| 16 |
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| 17 |
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| 18 | class Tracer(object):
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| 19 | # Limit to 10M events by default.
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| 20 | def __init__(self, max_events=10e6):
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| 21 | self.pid = os.getpid()
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| 22 | # append
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| 23 | self.event_strs = cStringIO.StringIO()
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| 24 |
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| 25 | # After max_events we stop recording
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| 26 | self.max_events = max_events
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| 27 | self.num_events = 0
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| 28 | self.depth = 0
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| 29 |
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| 30 | # Python VM callback
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| 31 | def OnEvent(self, frame, event_type, arg):
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| 32 | # Test overhead
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| 33 | # 7.5 seconds. Geez. That's crazy high.
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| 34 | # The baseline is 2.7 seconds, and _lsprof takes 3.8 seconds.
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| 35 |
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| 36 | # I guess that's why pytracing is a decorator and only works on one part of
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| 37 | # the program.
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| 38 | # pytracing isn't usable with large programs. It can't run abuild -h.
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| 39 |
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| 40 | # What I really want is the nicer visualization. I don't want the silly
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| 41 | # cProfile output.
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| 42 |
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| 43 | self.num_events += 1
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| 44 | name = frame.f_code.co_name
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| 45 | filename = frame.f_code.co_filename
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| 46 | if event_type in ('call', 'c_call'):
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| 47 | self.depth += 1
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| 48 |
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| 49 | record = '%s%s\t%s\t%s\t%s\t%s\n' % (
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| 50 | ' ' * self.depth, event_type, filename, frame.f_lineno, name, arg)
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| 51 | self.event_strs.write(record)
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| 52 |
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| 53 | if event_type in ('return', 'c_return'):
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| 54 | self.depth -= 1
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| 55 |
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| 56 | return
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| 57 |
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| 58 | # NOTE: Do we want a struct.pack version eventually?
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| 59 | #self.event_strs.write('')
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| 60 |
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| 61 | def Start(self):
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| 62 | sys.setprofile(self.OnEvent)
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| 63 |
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| 64 | def Stop(self, path):
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| 65 | sys.setprofile(None)
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| 66 | # Only one process should write out the file!
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| 67 | if os.getpid() != self.pid:
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| 68 | return
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| 69 |
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| 70 | # TODO:
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| 71 | # - report number of events?
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| 72 | # - report number of bytes?
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| 73 | print('num_events: %d' % self.num_events, file=sys.stderr)
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| 74 | print('Writing to %r' % path, file=sys.stderr)
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| 75 | with open(path, 'w') as f:
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| 76 | f.write(self.event_strs.getvalue())
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| 77 |
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| 78 |
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| 79 | def main(argv):
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| 80 | t = Tracer()
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| 81 | import urlparse
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| 82 | t.Start()
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| 83 | print(urlparse.urlparse('http://example.com/foo'))
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| 84 | t.Stop('demo.pytrace')
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| 85 |
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| 86 |
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| 87 | if __name__ == '__main__':
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| 88 | try:
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| 89 | main(sys.argv)
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| 90 | except RuntimeError as e:
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| 91 | print >> sys.stderr, 'FATAL: %s' % e
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| 92 | sys.exit(1)
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