When multiple threads all need to acquire the same runtime.mutex, make
sure that none of them has to wait for too long. Measure how long a
single thread can capture the mutex, and how long individual other
threads must go between having a turn with the mutex.
For #68578
Change-Id: I56ecc551232f9c2730c128a9f8eeb7bd45c2d3b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/622995
Auto-Submit: Rhys Hiltner <rhys.hiltner@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>