[all-commits] [llvm/llvm-project] 728b98: ThreadPool: grow the pool only as needed

[bjacob via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 728b982bb2aec5a5e9c887a7b0181ee360b27b54
      https://github.com/llvm/llvm-project/commit/728b982bb2aec5a5e9c887a7b0181ee360b27b54
  Author: Benoit Jacob <benoitjacob at google.com>
  Date:   2021-12-03 (Fri, 03 Dec 2021)

  Changed paths:
    M llvm/include/llvm/Support/ThreadPool.h
    M llvm/lib/Support/ThreadPool.cpp

  Log Message:
  -----------
  ThreadPool: grow the pool only as needed

On my 96-core cloudtop 'machine', it seems unnecessary to always start
96 threads upfront... particularly as the ThreadPool is created even
with -mlir-disable-threading. Things like the resuling spew in GDB and
the obfuscated output of `(gdb) info threads` are my motivation here,
but it probably also doesn't hurt for at least some efficiency metrics to
avoid creating many threads upfront.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D115019