tree 6bd0b264185d6c1093bfab9fe589f11095a61101
parent 42c763b07533ae24033f1ebca616f04de4e359b2
author Tejun Heo <tj@kernel.org> 1681848675 -1000
committer Tejun Heo <tj@kernel.org> 1681848708 -1000

workqueue: Add pwq->stats[] and a monitoring script

Currently, the only way to peer into workqueue operations is through
tracing. While possible, it isn't easy or convenient to monitor
per-workqueue behaviors over time this way. Let's add pwq->stats[] that
track relevant events and a drgn monitoring script -
tools/workqueue/wq_monitor.py.

It's arguable whether this needs to be configurable. However, it currently
only has seven counters and the runtime overhead shouldn't be noticeable
given that they're on pwq's which are per-cpu on per-cpu workqueues and
per-numa-node on unbound ones. Let's keep it simple for the time being.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>