RFC: XRay FDR/Profiling Mode Moving to Post-Commit Review

Hi llvm-dev,

I've recently been working on improving the profiling mode for XRay in
compiler-rt [0] and am ramping up efforts to do the same for
flight-data recorder mode. The changes are generally in the direction
of reducing the overheads (measured through benchmarks in the
test-suite) and addressing some feature requests/bugs.

In the interest of addressing these changes in a timely manner, I'm
going to start doing post-commit reviews for the profiling mode
patches in compiler-rt. Keith Wyss has been the primary reviewer for
XRay patches and has agreed to do the reviews post-commit as well.

Note that profiling mode for XRay is currently an optional component
of XRay and is still under active development.

If you have any questions and/or concerns about this, please feel free
to contact me either directly or through the mailing list.

Also note that there's no official code owner for XRay yet (hence the
message to the community).

With that said, help in code reviews for XRay would be most appreciated.

At the time of this writing, there are a number of patches addressing
performance and/or feature requests which are low-risk and are part of
ongoing active development:

- ⚙ D49217 [XRay][compiler-rt] Simplify Allocator Implementation
- ⚙ D49359 [XRay][compiler-rt] FDR Mode: Allow multiple runs
- ⚙ D49363 [XRay][compiler-rt] Segmented Array: Simplify and Optimise

My intent is to land these in the next few hours and iterate on
post-commit review comments.

Cheers

[0] http://lists.llvm.org/pipermail/llvm-dev/2018-February/121237.html

Hi llvm-dev,

...

My intent is to land these in the next few hours and iterate on
post-commit review comments.

I sent this message in haste, this should instead say:

If it's alright with the community, I would like to land these in the
next few days and iterate on post-commit review.

Feedback would be most appreciated.

Cheers

As long as your changes are under https://llvm.org/docs/DeveloperPolicy.html#code-reviews I don’t see any problems. Incrementally adding your work and having it done in post shouldn’t be a problem. If there’s some large or major change then it’s probably good to send it out for others to look at - no different than any other part of llvm.

-eric