Re: [PATCH v6 0/7] locking: contended_release tracepoint instrumentation

[Peter Zijlstra]

On Tue, May 05, 2026 at 05:09:29PM +0000, Dmitry Ilvokhin wrote:

> This series adds a contended_release tracepoint that fires on the
> holder side when a lock with waiters is released. This provides:
> 
> - Hold time estimation: when the holder's own acquisition was
>   contended, its contention_end (acquisition) and contended_release
>   can be correlated to measure how long the lock was held under
>   contention.
> 
> - The holder's stack at release time, which may differ from what perf lock
>   contention --lock-owner captures if the holder does significant work between
>   the waiter's arrival and the unlock.
> 
> Note: for reader/writer locks, the tracepoint fires for every reader
> releasing while a writer is waiting, not only for the last reader.

And for qspinlock.

I am really not sure this is worth the overhead for qspinlock / rwlock.