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[Python-Dev] Speeding up CPython 5-10%

Cesare Di Mauro cesare.di.mauro at gmail.com
Wed May 18 12:35:30 EDT 2016 
2016-05-17 8:25 GMT+02:00 <zreed at fastmail.com>:

> In the project https://github.com/zachariahreed/byteasm I mentioned on
> the list earlier this month, I have a pass that to computes stack usage
> for a given sequence of bytecodes. It seems to be a fair bit more
> agressive than cpython. Maybe it's more generally useful. It's pure
> python rather than C though.
>

IMO it's too big, resource hungry, and slower, even if you convert it in C.

If you take a look at the current stackdepth_walk function which CPython
uses, it's much smaller (not even 50 lines in simple C code) and quite
efficient.

Currently the problem is that it doesn't return the maximum depth of the
tree, but it updates the intermediate/current maximum, and *then* it uses
it for the subsequent calculations. So, the depth artificially grows, like
in the reported cases.

It doesn't require a complete rewrite, but spending some time for
fine-tuning it.

Regards
Cesare
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