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On Sun, 7 Aug 2022 10:27:03 -0400 Cristian Rodríguez wrote:
On Thu, Aug 4, 2022 at 12:40 PM Martin Jambor <mjambor@suse.cz> wrote:
Over the weekend, I have quickly gathered some SPEC CPU benchmarks results comparing the different x86_64 versions:
Huh, Martin ..thanks for taking the time to do this..it was disappointing to the extreme. So is this a case of
a) most code been written "unaware" of vectorization b) the compiler is not aggressive enough c) we do not get warnings of this kind of code
or all of them..
other interpretations are something like: the results with the "common" instructions are not so bad, or the added instructions also can not do miracles. It is likely that the CPU makers and the compiler makers are also using the SPEC CPU benchmarks to evaluate their work and all the three paths could be comparatively well optimized in this respect. I think this low performance gain in dedicated CPU benchmarks suggests to avoid switching to -v2 or -v3 which would drive away users of CPUs which do not support them or force them to get new hardware and bring only tiny benefit to the users with CPUs which support them. Kind regards, Dieter