Lib/profile.py

#! /usr/bin/env python
#
# Class for profiling python code. rev 1.0  6/2/94
#
# Based on prior profile module by Sjoerd Mullender...
#   which was hacked somewhat by: Guido van Rossum
#
# See profile.doc for more information

"""Class for profiling Python code."""

# Copyright 1994, by InfoSeek Corporation, all rights reserved.
# Written by James Roskind
#
# Permission to use, copy, modify, and distribute this Python software
# and its associated documentation for any purpose (subject to the
# restriction in the following sentence) without fee is hereby granted,
# provided that the above copyright notice appears in all copies, and
# that both that copyright notice and this permission notice appear in
# supporting documentation, and that the name of InfoSeek not be used in
# advertising or publicity pertaining to distribution of the software
# without specific, written prior permission.  This permission is
# explicitly restricted to the copying and modification of the software
# to remain in Python, compiled Python, or other languages (such as C)
# wherein the modified or derived code is exclusively imported into a
# Python module.
#
# INFOSEEK CORPORATION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
# SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
# FITNESS. IN NO EVENT SHALL INFOSEEK CORPORATION BE LIABLE FOR ANY
# SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.



import sys
import os
import time
import marshal

__all__ = ["run","help","Profile"]

# Sample timer for use with
#i_count = 0
#def integer_timer():
#       global i_count
#       i_count = i_count + 1
#       return i_count
#itimes = integer_timer # replace with C coded timer returning integers

#**************************************************************************
# The following are the static member functions for the profiler class
# Note that an instance of Profile() is *not* needed to call them.
#**************************************************************************

def run(statement, filename=None):
    """Run statement under profiler optionally saving results in filename

    This function takes a single argument that can be passed to the
    "exec" statement, and an optional file name.  In all cases this
    routine attempts to "exec" its first argument and gather profiling
    statistics from the execution. If no file name is present, then this
    function automatically prints a simple profiling report, sorted by the
    standard name string (file/line/function-name) that is presented in
    each line.
    """
    prof = Profile()
    try:
        prof = prof.run(statement)
    except SystemExit:
        pass
    if filename is not None:
        prof.dump_stats(filename)
    else:
        return prof.print_stats()

# print help
def help():
    for dirname in sys.path:
        fullname = os.path.join(dirname, 'profile.doc')
        if os.path.exists(fullname):
            sts = os.system('${PAGER-more} ' + fullname)
            if sts: print '*** Pager exit status:', sts
            break
    else:
        print 'Sorry, can\'t find the help file "profile.doc"',
        print 'along the Python search path.'


if os.name == "mac":
    import MacOS
    def _get_time_mac(timer=MacOS.GetTicks):
        return timer() / 60.0

if hasattr(os, "times"):
    def _get_time_times(timer=os.times):
        t = timer()
        return t[0] + t[1]


class Profile:
    """Profiler class.

    self.cur is always a tuple.  Each such tuple corresponds to a stack
    frame that is currently active (self.cur[-2]).  The following are the
    definitions of its members.  We use this external "parallel stack" to
    avoid contaminating the program that we are profiling. (old profiler
    used to write into the frames local dictionary!!) Derived classes
    can change the definition of some entries, as long as they leave
    [-2:] intact (frame and previous tuple).  In case an internal error is
    detected, the -3 element is used as the function name.

    [ 0] = Time that needs to be charged to the parent frame's function.
           It is used so that a function call will not have to access the
           timing data for the parent frame.
    [ 1] = Total time spent in this frame's function, excluding time in
           subfunctions (this latter is tallied in cur[2]).
    [ 2] = Total time spent in subfunctions, excluding time executing the
           frame's function (this latter is tallied in cur[1]).
    [-3] = Name of the function that corresponds to this frame.
    [-2] = Actual frame that we correspond to (used to sync exception handling).
    [-1] = Our parent 6-tuple (corresponds to frame.f_back).

    Timing data for each function is stored as a 5-tuple in the dictionary
    self.timings[].  The index is always the name stored in self.cur[-3].
    The following are the definitions of the members:

    [0] = The number of times this function was called, not counting direct
          or indirect recursion,
    [1] = Number of times this function appears on the stack, minus one
    [2] = Total time spent internal to this function
    [3] = Cumulative time that this function was present on the stack.  In
          non-recursive functions, this is the total execution time from start
          to finish of each invocation of a function, including time spent in
          all subfunctions.
    [4] = A dictionary indicating for each function name, the number of times
          it was called by us.
    """

    bias = 0  # calibration constant

    def __init__(self, timer=None, bias=None):
        self.timings = {}
        self.cur = None
        self.cmd = ""

        if bias is None:
            bias = self.bias
        self.bias = bias     # Materialize in local dict for lookup speed.

        if timer is None:
            if os.name == 'mac':
                self.timer = MacOS.GetTicks
                self.dispatcher = self.trace_dispatch_mac
                self.get_time = _get_time_mac
            elif hasattr(time, 'clock'):
                self.timer = self.get_time = time.clock
                self.dispatcher = self.trace_dispatch_i
            elif hasattr(os, 'times'):
                self.timer = os.times
                self.dispatcher = self.trace_dispatch
                self.get_time = _get_time_times
            else:
                self.timer = self.get_time = time.time
                self.dispatcher = self.trace_dispatch_i
        else:
            self.timer = timer
            t = self.timer() # test out timer function
            try:
                length = len(t)
            except TypeError:
                self.get_time = timer
                self.dispatcher = self.trace_dispatch_i
            else:
                if length == 2:
                    self.dispatcher = self.trace_dispatch
                else:
                    self.dispatcher = self.trace_dispatch_l
                # This get_time() implementation needs to be defined
                # here to capture the passed-in timer in the parameter
                # list (for performance).  Note that we can't assume
                # the timer() result contains two values in all
                # cases.
                import operator
                def get_time_timer(timer=timer,
                                   reduce=reduce, reducer=operator.add):
                    return reduce(reducer, timer(), 0)
                self.get_time = get_time_timer
        self.t = self.get_time()
        self.simulate_call('profiler')

    # Heavily optimized dispatch routine for os.times() timer

    def trace_dispatch(self, frame, event, arg):
        timer = self.timer
        t = timer()
        t = t[0] + t[1] - self.t - self.bias

        if self.dispatch[event](self, frame,t):
            t = timer()
            self.t = t[0] + t[1]
        else:
            r = timer()
            self.t = r[0] + r[1] - t # put back unrecorded delta

    # Dispatch routine for best timer program (return = scalar, fastest if
    # an integer but float works too -- and time.clock() relies on that).

    def trace_dispatch_i(self, frame, event, arg):
        timer = self.timer
        t = timer() - self.t - self.bias
        if self.dispatch[event](self, frame,t):
            self.t = timer()
        else:
            self.t = timer() - t  # put back unrecorded delta

    # Dispatch routine for macintosh (timer returns time in ticks of
    # 1/60th second)

    def trace_dispatch_mac(self, frame, event, arg):
        timer = self.timer
        t = timer()/60.0 - self.t - self.bias
        if self.dispatch[event](self, frame, t):
            self.t = timer()/60.0
        else:
            self.t = timer()/60.0 - t  # put back unrecorded delta

    # SLOW generic dispatch routine for timer returning lists of numbers

    def trace_dispatch_l(self, frame, event, arg):
        get_time = self.get_time
        t = get_time() - self.t - self.bias

        if self.dispatch[event](self, frame, t):
            self.t = get_time()
        else:
            self.t = get_time() - t # put back unrecorded delta

    # In the event handlers, the first 3 elements of self.cur are unpacked
    # into vrbls w/ 3-letter names.  The last two characters are meant to be
    # mnemonic:
    #     _pt  self.cur[0] "parent time"   time to be charged to parent frame
    #     _it  self.cur[1] "internal time" time spent directly in the function
    #     _et  self.cur[2] "external time" time spent in subfunctions

    def trace_dispatch_exception(self, frame, t):
        rpt, rit, ret, rfn, rframe, rcur = self.cur
        if (rframe is not frame) and rcur:
            return self.trace_dispatch_return(rframe, t)
        self.cur = rpt, rit+t, ret, rfn, rframe, rcur
        return 1


    def trace_dispatch_call(self, frame, t):
        if self.cur and frame.f_back is not self.cur[-2]:
            rpt, rit, ret, rfn, rframe, rcur = self.cur
            if not isinstance(rframe, Profile.fake_frame):
                assert rframe.f_back is frame.f_back, ("Bad call", rfn,
                                                       rframe, rframe.f_back,
                                                       frame, frame.f_back)
                self.trace_dispatch_return(rframe, 0)
                assert (self.cur is None or \
                        frame.f_back is self.cur[-2]), ("Bad call",
                                                        self.cur[-3])
        fcode = frame.f_code
        fn = (fcode.co_filename, fcode.co_firstlineno, fcode.co_name)
        self.cur = (t, 0, 0, fn, frame, self.cur)
        timings = self.timings
        if fn in timings:
            cc, ns, tt, ct, callers = timings[fn]
            timings[fn] = cc, ns + 1, tt, ct, callers
        else:
            timings[fn] = 0, 0, 0, 0, {}
        return 1

    def trace_dispatch_return(self, frame, t):
        if frame is not self.cur[-2]:
            assert frame is self.cur[-2].f_back, ("Bad return", self.cur[-3])
            self.trace_dispatch_return(self.cur[-2], 0)

        # Prefix "r" means part of the Returning or exiting frame.
        # Prefix "p" means part of the Previous or Parent or older frame.

        rpt, rit, ret, rfn, frame, rcur = self.cur
        rit = rit + t
        frame_total = rit + ret

        ppt, pit, pet, pfn, pframe, pcur = rcur
        self.cur = ppt, pit + rpt, pet + frame_total, pfn, pframe, pcur

        timings = self.timings
        cc, ns, tt, ct, callers = timings[rfn]
        if not ns:
            # This is the only occurrence of the function on the stack.
            # Else this is a (directly or indirectly) recursive call, and
            # its cumulative time will get updated when the topmost call to
            # it returns.
            ct = ct + frame_total
            cc = cc + 1

        if pfn in callers:
            callers[pfn] = callers[pfn] + 1  # hack: gather more
            # stats such as the amount of time added to ct courtesy
            # of this specific call, and the contribution to cc
            # courtesy of this call.
        else:
            callers[pfn] = 1

        timings[rfn] = cc, ns - 1, tt + rit, ct, callers

        return 1


    dispatch = {
        "call": trace_dispatch_call,
        "exception": trace_dispatch_exception,
        "return": trace_dispatch_return,
        }


    # The next few functions play with self.cmd. By carefully preloading
    # our parallel stack, we can force the profiled result to include
    # an arbitrary string as the name of the calling function.
    # We use self.cmd as that string, and the resulting stats look
    # very nice :-).

    def set_cmd(self, cmd):
        if self.cur[-1]: return   # already set
        self.cmd = cmd
        self.simulate_call(cmd)

    class fake_code:
        def __init__(self, filename, line, name):
            self.co_filename = filename
            self.co_line = line
            self.co_name = name
            self.co_firstlineno = 0

        def __repr__(self):
            return repr((self.co_filename, self.co_line, self.co_name))

    class fake_frame:
        def __init__(self, code, prior):
            self.f_code = code
            self.f_back = prior

    def simulate_call(self, name):
        code = self.fake_code('profile', 0, name)
        if self.cur:
            pframe = self.cur[-2]
        else:
            pframe = None
        frame = self.fake_frame(code, pframe)
        self.dispatch['call'](self, frame, 0)

    # collect stats from pending stack, including getting final
    # timings for self.cmd frame.

    def simulate_cmd_complete(self):
        get_time = self.get_time
        t = get_time() - self.t
        while self.cur[-1]:
            # We *can* cause assertion errors here if
            # dispatch_trace_return checks for a frame match!
            self.dispatch['return'](self, self.cur[-2], t)
            t = 0
        self.t = get_time() - t


    def print_stats(self):
        import pstats
        pstats.Stats(self).strip_dirs().sort_stats(-1). \
                  print_stats()

    def dump_stats(self, file):
        f = open(file, 'wb')
        self.create_stats()
        marshal.dump(self.stats, f)
        f.close()

    def create_stats(self):
        self.simulate_cmd_complete()
        self.snapshot_stats()

    def snapshot_stats(self):
        self.stats = {}
        for func, (cc, ns, tt, ct, callers) in self.timings.iteritems():
            callers = callers.copy()
            nc = 0
            for callcnt in callers.itervalues():
                nc += callcnt
            self.stats[func] = cc, nc, tt, ct, callers


    # The following two methods can be called by clients to use
    # a profiler to profile a statement, given as a string.

    def run(self, cmd):
        import __main__
        dict = __main__.__dict__
        return self.runctx(cmd, dict, dict)

    def runctx(self, cmd, globals, locals):
        self.set_cmd(cmd)
        sys.setprofile(self.dispatcher)
        try:
            exec cmd in globals, locals
        finally:
            sys.setprofile(None)
        return self

    # This method is more useful to profile a single function call.
    def runcall(self, func, *args, **kw):
        self.set_cmd(`func`)
        sys.setprofile(self.dispatcher)
        try:
            return apply(func, args, kw)
        finally:
            sys.setprofile(None)


    #******************************************************************
    # The following calculates the overhead for using a profiler.  The
    # problem is that it takes a fair amount of time for the profiler
    # to stop the stopwatch (from the time it receives an event).
    # Similarly, there is a delay from the time that the profiler
    # re-starts the stopwatch before the user's code really gets to
    # continue.  The following code tries to measure the difference on
    # a per-event basis.
    #
    # Note that this difference is only significant if there are a lot of
    # events, and relatively little user code per event.  For example,
    # code with small functions will typically benefit from having the
    # profiler calibrated for the current platform.  This *could* be
    # done on the fly during init() time, but it is not worth the
    # effort.  Also note that if too large a value specified, then
    # execution time on some functions will actually appear as a
    # negative number.  It is *normal* for some functions (with very
    # low call counts) to have such negative stats, even if the
    # calibration figure is "correct."
    #
    # One alternative to profile-time calibration adjustments (i.e.,
    # adding in the magic little delta during each event) is to track
    # more carefully the number of events (and cumulatively, the number
    # of events during sub functions) that are seen.  If this were
    # done, then the arithmetic could be done after the fact (i.e., at
    # display time).  Currently, we track only call/return events.
    # These values can be deduced by examining the callees and callers
    # vectors for each functions.  Hence we *can* almost correct the
    # internal time figure at print time (note that we currently don't
    # track exception event processing counts).  Unfortunately, there
    # is currently no similar information for cumulative sub-function
    # time.  It would not be hard to "get all this info" at profiler
    # time.  Specifically, we would have to extend the tuples to keep
    # counts of this in each frame, and then extend the defs of timing
    # tuples to include the significant two figures. I'm a bit fearful
    # that this additional feature will slow the heavily optimized
    # event/time ratio (i.e., the profiler would run slower, fur a very
    # low "value added" feature.)
    #**************************************************************

    def calibrate(self, m, verbose=0):
        if self.__class__ is not Profile:
            raise TypeError("Subclasses must override .calibrate().")

        saved_bias = self.bias
        self.bias = 0
        try:
            return self._calibrate_inner(m, verbose)
        finally:
            self.bias = saved_bias

    def _calibrate_inner(self, m, verbose):
        get_time = self.get_time

        # Set up a test case to be run with and without profiling.  Include
        # lots of calls, because we're trying to quantify stopwatch overhead.
        # Do not raise any exceptions, though, because we want to know
        # exactly how many profile events are generated (one call event, +
        # one return event, per Python-level call).

        def f1(n):
            for i in range(n):
                x = 1

        def f(m, f1=f1):
            for i in range(m):
                f1(100)

        f(m)    # warm up the cache

        # elapsed_noprofile <- time f(m) takes without profiling.
        t0 = get_time()
        f(m)
        t1 = get_time()
        elapsed_noprofile = t1 - t0
        if verbose:
            print "elapsed time without profiling =", elapsed_noprofile

        # elapsed_profile <- time f(m) takes with profiling.  The difference
        # is profiling overhead, only some of which the profiler subtracts
        # out on its own.
        p = Profile()
        t0 = get_time()
        p.runctx('f(m)', globals(), locals())
        t1 = get_time()
        elapsed_profile = t1 - t0
        if verbose:
            print "elapsed time with profiling =", elapsed_profile

        # reported_time <- "CPU seconds" the profiler charged to f and f1.
        total_calls = 0.0
        reported_time = 0.0
        for (filename, line, funcname), (cc, ns, tt, ct, callers) in \
                p.timings.items():
            if funcname in ("f", "f1"):
                total_calls += cc
                reported_time += tt

        if verbose:
            print "'CPU seconds' profiler reported =", reported_time
            print "total # calls =", total_calls
        if total_calls != m + 1:
            raise ValueError("internal error: total calls = %d" % total_calls)

        # reported_time - elapsed_noprofile = overhead the profiler wasn't
        # able to measure.  Divide by twice the number of calls (since there
        # are two profiler events per call in this test) to get the hidden
        # overhead per event.
        mean = (reported_time - elapsed_noprofile) / 2.0 / total_calls
        if verbose:
            print "mean stopwatch overhead per profile event =", mean
        return mean

#****************************************************************************
def Stats(*args):
    print 'Report generating functions are in the "pstats" module\a'


# When invoked as main program, invoke the profiler on a script
if __name__ == '__main__':
    if not sys.argv[1:]:
        print "usage: profile.py scriptfile [arg] ..."
        sys.exit(2)

    filename = sys.argv[1]  # Get script filename

    del sys.argv[0]         # Hide "profile.py" from argument list

    # Insert script directory in front of module search path
    sys.path.insert(0, os.path.dirname(filename))

    run('execfile(' + `filename` + ')')