[Python-Dev] PyDict_SetItem hook

Thomas Wouters thomas at python.org
Thu Apr 2 20:41:07 CEST 2009

On Thu, Apr 2, 2009 at 04:16, John Ehresman <jpe at wingware.com> wrote:

> Collin Winter wrote:
>> Have you measured the impact on performance?
> I've tried to test using pystone, but am seeing more differences between
> runs than there is between python w/ the patch and w/o when there is no hook
> installed.  The highest pystone is actually from the binary w/ the patch,
> which I don't really believe unless it's some low level code generation
> affect.  The cost is one test of a global variable and then a switch to the
> branch that doesn't call the hooks.
> I'd be happy to try to come up with better numbers next week after I get
> home from pycon.

Pystone is pretty much a useless benchmark. If it measures anything, it's
the speed of the bytecode dispatcher (and it doesn't measure it particularly
well.) PyBench isn't any better, in my experience. Collin has collected a
set of reasonable benchmarks for Unladen Swallow, but they still leave a lot
to be desired. From the discussions at the VM and Language summits before
PyCon, I don't think anyone else has better benchmarks, though, so I would
suggest using Unladen Swallow's:

Thomas Wouters <thomas at python.org>

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