Examples of Benchmarking Programs

[mnatsuhara]

It was brought up during the MSVC STL Contributors Meetup (GH-921) that the maintainers often ask for benchmarking results in order to accept optimization changes. It would likely be easier for contributors to provide benchmarking results if we provided examples of the types of programs that we typically use, or options for how to approach the problem. We should provide examples/tips somewhere on the wiki.

[AlexGuteniev]

A good candidate issue is apparently #472
The fix itself is easy, all the challenge comes from the benchmark.

[AlexGuteniev]

There are some examples:

• add AVX-512 vector algorithms implementation #2104
• <charconv>: Report compiler optimization issues #1243
• make bitset use popcount with ISA detection out of loop #2201
• Optimize std::count even more for vector<👻> #2203
• <fstream>: Poor fstream performance on large files #1107
• Optimize random #256
• <xatomic.h>: Consider adding _mm_pause on x86/x64 #680 (comment)
  Maybe more, I didn't search very carefully

[StephanTLavavej]

@AlexGuteniev has pointed out that we've accumulated many examples of benchmarks in the repo itself, so we can go ahead and close this now.