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Title: Speedup inspect.Signature.bind
Type: performance Stage: resolved
Components: Library (Lib) Versions: Python 3.5
Status: closed Resolution: postponed
Dependencies: Superseder:
Assigned To: yselivanov Nosy List: asvetlov, brett.cannon, larry, ncoghlan, yselivanov
Priority: normal Keywords:

Created on 2015-04-08 17:37 by yselivanov, last changed 2022-04-11 14:58 by admin. This issue is now closed.

Messages (2)
msg240279 - (view) Author: Yury Selivanov (yselivanov) * (Python committer) Date: 2015-04-08 17:37
Right now the implementation of Signature.bind is very complex, which leads to a subpar performance. The only way to significantly speed it up is to employ code generation and cache (the other way it to rewrite it in C, but that's something I'd like to avoid). I'll upload an initial implementation soon.
msg243637 - (view) Author: Yury Selivanov (yselivanov) * (Python committer) Date: 2015-05-20 00:55
After some experiments, it looks like bind() is already pretty fast. The only way to increase its performance is to rewrite it in C.

I tried to approaches:

1. Refactor ._bind() to produce a high-level instruction set that can be cached, and is fast to iterate through and build BoundArguments.  Repo:


====================================  ===========  ==============  ===============
function / call                       bind (3.4)   bind cache hit  bind cache miss
====================================  ===========  ==============  ===============
() / ()                               0.716s       0.746s  (-4%)   0.799s  (-10%)
(a, b=1) / (10)                       1.140s       0.910s  (+20%)  1.294s  (-12%)
(a, b=1, *ar) / (10, 20, 30, 40)      1.352s       1.145s  (+15%)  1.520s  (-11%)
(a, b=1, **ar) / (10, 20, z=30, y=4)  1.364s       1.233s  (+10%)  1.660s  (-18%)
(a, b=1, *, z, **ar) / (1,2,z=3,y=4)  1.499s       1.363s  (+10%)  1.897s  (-26%)

2. Refactor ._bind() to compile a function that builds BoundArguments for te given args/kwargs shape.  This approach yields more-or-less same results as (1), but performance of cache-miss case is just terrible (-200%).  Compiling functions on the fly is expensive.  Repo to play with:

I'm closing this issue, until I (or someone else) can implement bind() in C (or come up with a faster pure-python implementation).
Date User Action Args
2022-04-11 14:58:15adminsetgithub: 68077
2015-05-20 00:55:29yselivanovsetstatus: open -> closed
resolution: postponed
messages: + msg243637

stage: needs patch -> resolved
2015-04-08 17:38:20yselivanovsettype: performance
stage: needs patch
2015-04-08 17:37:50yselivanovcreate