[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#789021, @hfinkel wrote:

> In https://reviews.llvm.org/D32272#789012, @kristof.beyls wrote:
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> > In https://reviews.llvm.org/D32272#789006, @hfinkel wrote:
> >
> > > 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.
> > >
> > >
> > > Can you please summarize the state of this and the eventual goal? It looks like:
> > >
> > > 1. Eventually, we need a new LNT plugin (i.e. something like what we have in LNTBased/*) that understands how to interpret the output of the Google benchmark library.
> >
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> > I hope this could all be done within the test-suite, probably extending test-suite/litsupport. I hope/think that no changes to LNT will be needed, but I haven't investigated myself.
>
> Just to be clear, LNTBased/* is in the test suite; LNT supports plugins and those can be in the test suite. That having been said, if we can do this just within litsupport, that potentially seems better. The key feature seems to be being able to report multiple benchmark timings per actual executable.




- The lit data format currently does not allow multiple values for a metric.
- I'm not sure I see why that would be needed here.
- It is easy to do some form of aggregation (like taking the minimum) in the litsupport code to reduce the result to a single number. And doesn't googletest already reduce the result to a single number?
- It shouldn't be too hard to extend lit to support other data formats (it's just passing along those metrics so there is little need to restrict them).


https://reviews.llvm.org/D32272