bpo-43950: optimize column table assembling with pre-sizing the column table

[isidentical]

The new resizing system works like this;

$ cat t.py a + a + a + b + c + a + a + a + b + c + a + a + a + b + c + a + a + a + b + c [repeated 99 more times] $ ./python t.py RESIZE: prev len = 32, new len = 66 FINAL SIZE: 56 ----------------------------------------------------- RESIZE: prev len = 32, new len = 66 RESIZE: prev len = 66, new len = 134 RESIZE: prev len = 134, new len = 270 RESIZE: prev len = 270, new len = 542 RESIZE: prev len = 542, new len = 1086 RESIZE: prev len = 1086, new len = 2174 RESIZE: prev len = 2174, new len = 4350 RESIZE: prev len = 4350, new len = 8702 FINAL SIZE: 8004 

So now we do considerably lower number of _PyBytes_Resize calls.

https://bugs.python.org/issue43950

Automerge-Triggered-By: GH:isidentical

[pablogsal]

I can confirm that this speeds up the allocation quite a lot as expected 👍

❯ time ./python -m test test_compile -m test_stack_overflow -v == CPython 3.11.0a0 (heads/optimize-co-positions:760daf9858, Jul 2 2021, 19:08:05) [GCC 11.1.0] == Linux-5.12.13-arch1-2-x86_64-with-glibc2.33 little-endian == cwd: /home/pablogsal/github/python/main/build/test_python_15988æ == CPU count: 36 == encodings: locale=UTF-8, FS=utf-8 0:00:00 load avg: 2.15 Run tests sequentially 0:00:00 load avg: 2.15 [1/1] test_compile test_stack_overflow (test.test_compile.TestSpecifics) ... ok ---------------------------------------------------------------------- Ran 1 test in 3.945s OK == Tests result: SUCCESS == 1 test OK. Total duration: 4.0 sec Tests result: SUCCESS ./python -m test test_compile -m test_stack_overflow -v 3.77s user 0.47s system 99% cpu 4.241 total 

[miss-islington]

@isidentical: Status check is done, and it's a success ❌ .

[isidentical]

concurrent_futures error, irrelevant, restarting the CI

[miss-islington]

@isidentical: Status check is done, and it's a success ✅ .

[miss-islington]

Sorry, I can't merge this PR. Reason: 3 of 5 required status checks have not succeeded: 2 expected..

[miss-islington]

@isidentical: Status check is done, and it's a success ✅ .