From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Ilvokhin <d@ilvokhin.com>
Cc: Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Boqun Feng <boqun@kernel.org>, Waiman Long <longman@redhat.com>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Juergen Gross <jgross@suse.com>,
Ajay Kaher <ajay.kaher@broadcom.com>,
Alexey Makhalov <alexey.makhalov@broadcom.com>,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@broadcom.com>,
Thomas Gleixner <tglx@kernel.org>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Arnd Bergmann <arnd@arndb.de>, Dennis Zhou <dennis@kernel.org>,
Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@gentwo.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
virtualization@lists.linux.dev, linux-arch@vger.kernel.org,
linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org,
kernel-team@meta.com
Subject: Re: [PATCH v6 0/7] locking: contended_release tracepoint instrumentation
Date: Wed, 13 May 2026 21:26:05 +0200 [thread overview]
Message-ID: <20260513192605.GA2545104@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <cover.1777999826.git.d@ilvokhin.com>
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.
prev parent reply other threads:[~2026-05-13 19:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-05 17:09 [PATCH v6 0/7] locking: contended_release tracepoint instrumentation Dmitry Ilvokhin
2026-05-05 17:09 ` [PATCH v6 1/7] tracing/lock: Remove unnecessary linux/sched.h include Dmitry Ilvokhin
2026-05-05 17:09 ` [PATCH v6 2/7] locking/percpu-rwsem: Extract __percpu_up_read() Dmitry Ilvokhin
2026-05-05 17:09 ` [PATCH v6 3/7] locking: Add contended_release tracepoint to sleepable locks Dmitry Ilvokhin
2026-05-05 17:09 ` [PATCH v6 4/7] locking: Factor out queued_spin_release() Dmitry Ilvokhin
2026-05-13 15:37 ` Steven Rostedt
2026-05-05 17:09 ` [PATCH v6 5/7] locking: Add contended_release tracepoint to qspinlock Dmitry Ilvokhin
2026-05-13 15:41 ` Steven Rostedt
2026-05-13 19:33 ` Peter Zijlstra
2026-05-05 17:09 ` [PATCH v6 6/7] locking: Factor out __queued_read_unlock()/__queued_write_unlock() Dmitry Ilvokhin
2026-05-13 15:41 ` Steven Rostedt
2026-05-05 17:09 ` [PATCH v6 7/7] locking: Add contended_release tracepoint to qrwlock Dmitry Ilvokhin
2026-05-13 15:43 ` Steven Rostedt
2026-05-13 19:26 ` Peter Zijlstra [this message]
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