[issue17628] str==str: compare the first and last character before calling memcmp()

[STINNER Victor]

STINNER Victor added the comment:

benchmark2: Results on a slower computer. Comparing equal strings is much faster with the patch. Example:

equal, 'A', 1000000          |  945 us (*) | 1.25 ms (+32%)

I don't understand why the patch makes the comparaison much slower, since most time is supposed to be spend in memcmp()?

Is it because I starts at the second character to compare strings, instead of the first character? Memory alignment issue?

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Added file: http://bugs.python.org/file29672/benchmark2

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