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Improve performance of find_max_char #122901
Description
Feature or enhancement
Proposal:
find_max_char is called each time a string is created.
By reducing the amount of tests, the performance can be improved considerably.
python -m pyperf timeit -s "b=('a' *1000+ '\u019f'*2)" "b[:-1]"
+-----------+--------+----------------------+
| Benchmark | ref | patch |
+===========+========+======================+
| timeit | 442 ns | 388 ns: 1.14x faster |
+-----------+--------+----------------------+
Has this already been discussed elsewhere?
This is a minor feature, which does not need previous discussion elsewhere
Links to previous discussion of this feature:
No response
Activity
terryjreedy commentedon Aug 11, 2024
@vstinner Should you or someone else look at this? Should OP say more about idea of patch? Is the above the proper speed test?
picnixz commentedon Aug 13, 2024
I would also look at the arguments in #120212.
Personally, I would include in the benchmarks:
By the way, is your build a release or a PGO (maybe with LTO) build?
vstinner commentedon Aug 27, 2024
@ruema: Would you mind to run more benchmarks? See previous @picnixz comment about that.
rhpvorderman commentedon Sep 10, 2024
This is basically the same as #120212 but with larger chunks. Given that this approach unifies the find_max_char functions for all
char sizes, from a maintainability standpoint it is better than #120212.
I would add benchmarks for line by line reading.
for line in file_descriptoris a very common pattern.vstinner commentedon Sep 18, 2024
Would it be possible to have a few more benchmarks on this change to have an idea if it's worth it or not?