[PATCH] D38119: [XRay][compiler-rt] Use a hand-written circular buffer in BufferQueue

[Dean Michael Berris via Phabricator via llvm-commits]

dberris added a comment.

In https://reviews.llvm.org/D38119#883667, @dblaikie wrote:

> Why all the logging & test changes in the latest update? Did they slip in accidentally?


Not accidental -- it turns out that sometimes, `f2()` doesn't last long enough to be logged, and despite the threshold for deltas being 0 it seems we are still able to get to that state.

That seems like a separate "bug" that I need to investigate.

Adding the fences in the test made it exhibit the problem less, so I kept it.

The atomic global is there to ensure that there's an observable dependency between the threads writing to the variable and the output of the main function.


https://reviews.llvm.org/D38119