[PATCH] D32272: [XRay] Add Google Benchmark library + initial XRay benchmarks

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

In https://reviews.llvm.org/D32272#788932, @dberris wrote:

> LGTM for the most part, thanks for making the changes, it's much simpler now.
>
> Thoughts @MatzeB? I think we can work on running/reporting the microbenchmarks data later, in changes to LNT.


My comment from last time still stands:

- Short of having a lit plugin that extracts the numbers reported by googletest we are currently measuring the time that the executable runs.
- My impression was that this time varies because googletest will do variable numbers of iterations. My understanding is that `--benchmark_repetitions` does not fix that.
- Without stable numbers coming out of this, LNT will report regressions that are not real and cannot be fixed.


https://reviews.llvm.org/D32272