[Python-Dev] Timing results for scope.py (was Re: Object finalization for local (ie function) scopes)

[Oliver Schoenborn]

I created two functions: one empty and one that opens a file and writes a
line and closes it. I ran once without scope-guard, and once with for each.

Short unscoped (us):   17.485010669
Short and scoped (us): 72.8106022384
Long unscoped (ms):    19.7690964161
Long and scoped (ms):  20.380344323

Here is the code with the tests:

import sys

def ScopeGuarded(func):
    return lambda *args, **kwargs: ScopeGuardian(func, *args, **kwargs)

_funcStack = []

def ScopeGuardian(func, *args, **kwargs):
    try:
        scopedObjs = []
        _funcStack.append(scopedObjs)
        func(*args, **kwargs)

    finally:
        _funcStack.pop()
        if scopedObjs != []:
            scopedObjs.reverse() # destroy in reverse order from creation
            for obj in scopedObjs:
                obj.finalizeMaster()


def testTimingShort(scoped=False):
    def fastFun():
        pass

    if scoped:
        fastFun = ScopeGuarded(fastFun)
    fastFun()


def testTimingLong(scoped=False):
    def slowFun():
        ff = file('asdfaf','w')
        ff.write('asdfaf')
        ff.close()

    if scoped:
        slowFun = ScopeGuarded(slowFun)
    slowFun()


def testTiming():
    from timeit import Timer
    tts =  Timer('testTimingShort()',     'from __main__ import
testTimingShort')
    ttss = Timer('testTimingShort(True)', 'from __main__ import
testTimingShort')
    ttl =  Timer('testTimingLong()',      'from __main__ import
testTimingLong')
    ttls = Timer('testTimingLong(True)',  'from __main__ import
testTimingLong')

    tms  = tts.timeit(10000)*100
    print "Short unscoped (us):  ", tms
    tmss = ttss.timeit(10000)*100
    print "Short and scoped (us):", tmss
    tml  = ttl.timeit(100)*10
    print "Long unscoped (ms):   ", tml
    tmls = ttls.timeit(100)*10
    print "Long and scoped (ms): ", tmls

    print "For long, scoped takes %s%% longer than unscoped" %
((tmls/tml-1)*100)


if __name__ == '__main__':
    testTiming()