[all-commits] [llvm/llvm-project] e72ad3: tsan: use semaphores for thread creation synchroni...

[Dmitry Vyukov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e72ad3c19a15a5716617f8c1d273ca506dc68276
      https://github.com/llvm/llvm-project/commit/e72ad3c19a15a5716617f8c1d273ca506dc68276
  Author: Dmitry Vyukov <dvyukov at google.com>
  Date:   2021-08-03 (Tue, 03 Aug 2021)

  Changed paths:
    M compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp

  Log Message:
  -----------
  tsan: use semaphores for thread creation synchronization

We currently use ad-hoc spin waiting to synchronize thread creation
and thread start both ways. But spinning tend to degrade ungracefully
under high contention (lots of threads are created at the same time).
Use semaphores for synchronization instead.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D107337