[pypy-dev] pypy + cProfile

[Armin Rigo]

Hi Stanislav,

On 14 May 2015 at 08:37, Stanislav Bohm <stanislav.bohm at vsb.cz> wrote:
> I have tried some standard benchmarks and my other python programs, and
> cProfile makes things slower.
> Hence, Aislinn is the only program where I can reproduce the weird behavior.

Then it looks likely to be a "randomness" issue: details in your
program are JIT-compiled differently when cProfile is enabled.  For
example, cProfile makes traces longer and this can change a few
heuristics.  It's likely that by tweaking your program a bit randomly
you can also get the same 20% variation.

Not all program exhibit this kind of detail-dependent behavior, but
one or two of our benchmark do: while most benchmarks have a
relatively stable performance, there are a couple of them whose
performance occasionally jumps between two known values.  (The
randomness in this case seem to be triggered by development inside
PyPy rather than changes to the benchmarks, but it's the same issue.)


A bientôt,

Armin.