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  • Committer: Martin Pool
  • Date: 2010-01-29 14:09:05 UTC
  • mto: This revision was merged to the branch mainline in revision 4992.
  • Revision ID: mbp@sourcefrog.net-20100129140905-2uiarb6p8di1ywsr
Correction to url

from review: https://code.edge.launchpad.net/~mbp/bzr/doc/+merge/18250

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bzrlib/lsprof.py
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import threading
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from _lsprof import Profiler, profiler_entry
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from bzrlib import errors
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__all__ = ['profile', 'Stats']
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    raised, pass in a closure that will catch the exceptions and transform them
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    appropriately for your driver function.
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    Important caveat: only one profile can execute at a time. See BzrProfiler
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    for details.
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    :return: The functions return value and a stats object.
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    """
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    profiler = BzrProfiler()
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    To use it, create a BzrProfiler and call start() on it. Some arbitrary
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    time later call stop() to stop profiling and retrieve the statistics
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    from the code executed in the interim.
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    Note that profiling involves a threading.Lock around the actual profiling.
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    This is needed because profiling involves global manipulation of the python
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    interpreter state. As such you cannot perform multiple profiles at once.
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    Trying to do so will lock out the second profiler unless the global 
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    bzrlib.lsprof.BzrProfiler.profiler_block is set to 0. Setting it to 0 will
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    cause profiling to fail rather than blocking.
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    """
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    profiler_block = 1
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    """Serialise rather than failing to profile concurrent profile requests."""
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    profiler_lock = threading.Lock()
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    """Global lock used to serialise profiles."""
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    def start(self):
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        """Start profiling.
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        """
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        self._g_threadmap = {}
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        self.p = Profiler()
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        permitted = self.__class__.profiler_lock.acquire(
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            self.__class__.profiler_block)
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        if not permitted:
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            raise errors.InternalBzrError(msg="Already profiling something")
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        try:
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            self.p.enable(subcalls=True)
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            threading.setprofile(self._thread_profile)
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        except:
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            self.__class__.profiler_lock.release()
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            raise
 
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        self.p.enable(subcalls=True)
 
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        threading.setprofile(self._thread_profile)
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    def stop(self):
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        """Stop profiling.
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        :return: A bzrlib.lsprof.Stats object.
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        """
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        try:
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            self.p.disable()
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            for pp in self._g_threadmap.values():
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                pp.disable()
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            threading.setprofile(None)
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            p = self.p
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            self.p = None
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            threads = {}
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            for tid, pp in self._g_threadmap.items():
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                threads[tid] = Stats(pp.getstats(), {})
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            self._g_threadmap = None
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            return Stats(p.getstats(), threads)
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        finally:
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            self.__class__.profiler_lock.release()
 
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        self.p.disable()
 
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        for pp in self._g_threadmap.values():
 
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            pp.disable()
 
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        threading.setprofile(None)
 
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        p = self.p
 
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        self.p = None
 
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        threads = {}
 
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        for tid, pp in self._g_threadmap.items():
 
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            threads[tid] = Stats(pp.getstats(), {})
 
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        self._g_threadmap = None
 
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        return Stats(p.getstats(), threads)
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    def _thread_profile(self, f, *args, **kwds):
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        # we lose the first profile point for a new thread in order to