    """
    Stores some values related to performance. These are usually set by
    Launch.py or AppServer.py.

    To get profiling going, locate the "runProfile = 0" line towards the
    top of WebKit/Launch.py and change the "0" to a "1". When the app
    server shuts down it will write Webware/profile.pstats which can be
    quickly examined from the command line:

        $ cd Webware
        $ bin/printprof.py profile.pstats

    You might also wish to dump the profiling stats on demand (as in, by
    clicking or reloading a URL for that purpose). Read further for
    details.

    The variables in this module are:

    profiler
        An instance of Python's profile.Profiler, but only if Launch.py is
        modified to say "runProfile = 1". Otherwise, this is None. You
        could access this from a servlet in order to dump stats:

            from WebKit.Profiler import profiler
            profiler.dump_stats('profile.pstats')

        Or more conveniently:
            from WebKit.Profiler import dumpStats
            dumpStats()

        With some work, you could dump them directly to the page in a
        readable format.

    startTime
        The earliest recordable time() when the app server program was
        launched.

    readyTime
    readyDuration
        The time() and duration from startTime for when the app server
        was ready to start accepting requests. A smaller readyDuration
        makes application reloading faster which is useful when
        developing with AutoReload on.
    """

    profiler      = None
    startTime     = None
    readyTime     = None
    readyDuration = None

    # Convenience

    statsFilename = 'profile.pstats'

    def dumpStats():
        profiler.dump_stats(statsFilename)