runtime/metrics: add /sync/mutex/wait/total:seconds metric

This change adds a metric to the runtime/metrics package which tracks
total mutex wait time for sync.Mutex and sync.RWMutex. The purpose of
this metric is to be able to quickly get an idea of the total mutex wait
time.

The implementation of this metric piggybacks off of the existing G
runnable tracking infrastructure, as well as the wait reason set on a G
when it goes into _Gwaiting.

Fixes #49881.

Change-Id: I4691abf64ac3574bec69b4d7d4428b1573130517
Reviewed-on: https://go-review.googlesource.com/c/go/+/427618
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Michael Anthony Knyszek 2022-08-31 21:34:23 +00:00 committed by Gopher Robot
parent 686b38b5b2
commit 63ceff95fa
7 changed files with 221 additions and 25 deletions

View file

@ -272,5 +272,12 @@ Below is the full list of supported metrics, ordered lexicographically.
/sched/latencies:seconds
Distribution of the time goroutines have spent in the scheduler
in a runnable state before actually running.
/sync/mutex/wait/total:seconds
Approximate cumulative time goroutines have spent blocked on a
sync.Mutex or sync.RWMutex. This metric is useful for identifying
global changes in lock contention. Collect a mutex or block
profile using the runtime/pprof package for more detailed
contention data.
*/
package metrics