[issue37587] JSON loads performance improvement for long strings

[Inada Naoki]

Inada Naoki <songofacandy at gmail.com> added the comment:

I tried without PGO and confirmed performance improved on GCC 7.2.0.
No change on other compiler versions.


$ ./python -m pyperf timeit  -s "import json; x = json.dumps({'k': '1' * 2 ** 20})" "json.loads(x)"

old: 9211e2
new: 8a758f

gcc (Ubuntu 8.3.0-6ubuntu1) 8.3.0

old: Mean +- std dev: 721 us +- 0 us
new: Mean +- std dev: 722 us +- 0 us


gcc-7 (Ubuntu 7.4.0-8ubuntu1) 7.4.0

old: Mean +- std dev: 1.03 ms +- 0.00 ms
new: Mean +- std dev: 726 us +- 0 us


clang version 7.0.1-8 (tags/RELEASE_701/final)

old: Mean +- std dev: 721 us +- 1 us
new: Mean +- std dev: 722 us +- 0 us


clang version 8.0.0-3 (tags/RELEASE_800/final)

old: Mean +- std dev: 721 us +- 0 us
new: Mean +- std dev: 721 us +- 1 us

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<https://bugs.python.org/issue37587>
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