[PATCH 2 of 2] util: add a timed function for use during development

Augie Fackler raf at durin42.com
Mon Feb 25 09:17:43 CST 2013


On Sat, Feb 23, 2013 at 11:05:04PM +0100, Benoit Boissinot wrote:
> On Thu, Feb 21, 2013 at 10:33 PM, Bryan O'Sullivan <bos at serpentine.com>wrote:
>
> > # HG changeset patch
> > # User Bryan O'Sullivan <bryano at fb.com>
> > # Date 1361482360 28800
> > # Node ID 95cb8d7754a7a28f52f82a332bf1163eb6dea202
> > # Parent  19d3300883ce1407d0b527549a82f25d3f182873
> > util: add a timed function for use during development
> >
> > I often want to measure the cost of a function call before/after
> > an optimization, where using top level "hg --time" timing introduces
> > enough other noise that I can't tell if my efforts are having an
> > effect.
> >
> > This decorator allows a developer to measure a function's cost with
> > finer granularity.
> >
> > diff --git a/mercurial/util.py b/mercurial/util.py
> > --- a/mercurial/util.py
> > +++ b/mercurial/util.py
> > @@ -1872,3 +1872,45 @@ def isatty(fd):
> >          return fd.isatty()
> >      except AttributeError:
> >          return False
> > +
> > +timecount = unitcount(
> > +    (1, 1e3, _('%.0f s')),
> > +    (100, 1, _('%.1f s')),
> > +    (10, 1, _('%.2f s')),
> > +    (1, 1, _('%.3f s')),
> > +    (100, 1e-3, _('%.1f ms')),
> > +    (10, 1e-3, _('%.2f ms')),
> > +    (1, 1e-3, _('%.3f ms')),
> > +    (100, 1e-6, _('%.1f us')),
> > +    (10, 1e-6, _('%.2f us')),
> > +    (1, 1e-6, _('%.3f us')),
> > +    (100, 1e-9, _('%.1f ns')),
> > +    (10, 1e-9, _('%.2f ns')),
> > +    (1, 1e-9, _('%.3f ns')),
> > +    )
> > +
> > +_timenesting = [0]
> > +
> > +def timed(func):
> > +    '''Report the execution time of a function call to stderr.
> > +
> > +    During development, use as a decorator when you need to measure
> > +    the cost of a function, e.g. as follows:
> > +
> > +    @util.timed
> > +    def foo(a, b, c):
> > +        pass
> > +    '''
> > +
> > +    def wrapper(*args, **kwargs):
> > +        start = time.time()
> > +        _timenesting[0] += 2
> >
>
> I'm a bit puzzled by the 2. Any hint?

That's the amount nested timed invocations will indent. It's clever,
but clear upon basic reading of the code IMO.

>
>
> > +        try:
> > +            return func(*args, **kwargs)
> > +        finally:
> > +            elapsed = time.time() - start
> > +            _timenesting[0] -= 2
> > +            sys.stderr.write('%s%s: %s\n' %
> > +                             (' ' * _timenesting[0], func.__name__,
> > +                              timecount(elapsed)))
> > +    return wrapper
> > _______________________________________________
> > Mercurial-devel mailing list
> > Mercurial-devel at selenic.com
> > http://selenic.com/mailman/listinfo/mercurial-devel
> >

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