← Back to branch summary

~bzr-pqm/bzr/bzr.dev

« back to all changes in this revision

Viewing changes to bzrlib/lsprof.py

  • Committer: Martin Pool
  • Date: 2010-04-01 04:41:18 UTC
  • mto: This revision was merged to the branch mainline in revision 5128.
  • Revision ID: mbp@sourcefrog.net-20100401044118-shyctqc02ob08ngz
ignore .testrepository

Show diffs side-by-side

added added

removed removed

Lines of Context:
bzrlib/lsprof.py
10
10
import threading
11
11
from _lsprof import Profiler, profiler_entry
12
12
 
13
 
from bzrlib import errors
14
13
 
15
14
__all__ = ['profile', 'Stats']
16
15
 
21
20
    raised, pass in a closure that will catch the exceptions and transform them
22
21
    appropriately for your driver function.
23
22
 
24
 
    Important caveat: only one profile can execute at a time. See BzrProfiler
25
 
    for details.
26
 
 
27
23
    :return: The functions return value and a stats object.
28
24
    """
29
25
    profiler = BzrProfiler()
45
41
    To use it, create a BzrProfiler and call start() on it. Some arbitrary
46
42
    time later call stop() to stop profiling and retrieve the statistics
47
43
    from the code executed in the interim.
48
 
 
49
 
    Note that profiling involves a threading.Lock around the actual profiling.
50
 
    This is needed because profiling involves global manipulation of the python
51
 
    interpreter state. As such you cannot perform multiple profiles at once.
52
 
    Trying to do so will lock out the second profiler unless the global 
53
 
    bzrlib.lsprof.BzrProfiler.profiler_block is set to 0. Setting it to 0 will
54
 
    cause profiling to fail rather than blocking.
55
44
    """
56
45
 
57
 
    profiler_block = 1
58
 
    """Serialise rather than failing to profile concurrent profile requests."""
59
 
 
60
 
    profiler_lock = threading.Lock()
61
 
    """Global lock used to serialise profiles."""
62
 
 
63
46
    def start(self):
64
47
        """Start profiling.
65
48
        
68
51
        """
69
52
        self._g_threadmap = {}
70
53
        self.p = Profiler()
71
 
        permitted = self.__class__.profiler_lock.acquire(
72
 
            self.__class__.profiler_block)
73
 
        if not permitted:
74
 
            raise errors.InternalBzrError(msg="Already profiling something")
75
 
        try:
76
 
            self.p.enable(subcalls=True)
77
 
            threading.setprofile(self._thread_profile)
78
 
        except:
79
 
            self.__class__.profiler_lock.release()
80
 
            raise
 
54
        self.p.enable(subcalls=True)
 
55
        threading.setprofile(self._thread_profile)
81
56
 
82
57
    def stop(self):
83
58
        """Stop profiling.
87
62
 
88
63
        :return: A bzrlib.lsprof.Stats object.
89
64
        """
90
 
        try:
91
 
            self.p.disable()
92
 
            for pp in self._g_threadmap.values():
93
 
                pp.disable()
94
 
            threading.setprofile(None)
95
 
            p = self.p
96
 
            self.p = None
97
 
            threads = {}
98
 
            for tid, pp in self._g_threadmap.items():
99
 
                threads[tid] = Stats(pp.getstats(), {})
100
 
            self._g_threadmap = None
101
 
            return Stats(p.getstats(), threads)
102
 
        finally:
103
 
            self.__class__.profiler_lock.release()
 
65
        self.p.disable()
 
66
        for pp in self._g_threadmap.values():
 
67
            pp.disable()
 
68
        threading.setprofile(None)
 
69
        p = self.p
 
70
        self.p = None
 
71
        threads = {}
 
72
        for tid, pp in self._g_threadmap.items():
 
73
            threads[tid] = Stats(pp.getstats(), {})
 
74
        self._g_threadmap = None
 
75
        return Stats(p.getstats(), threads)
104
76
 
105
77
    def _thread_profile(self, f, *args, **kwds):
106
78
        # we lose the first profile point for a new thread in order to