From: Davidlohr Bueso <dave@stgolabs.net>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
linux-kernel@vger.kernel.org,
"Thomas Gleixner" <tglx@linutronix.de>,
"Paul E . McKenney" <paulmck@kernel.org>,
"Boqun Feng" <boqun.feng@gmail.com>,
"H . Peter Anvin" <hpa@zytor.com>, "Paul Turner" <pjt@google.com>,
linux-api@vger.kernel.org,
"Christian Brauner" <brauner@kernel.org>,
"Florian Weimer" <fw@deneb.enyo.de>,
David.Laight@ACULAB.COM, carlos@redhat.com,
"Peter Oskolkov" <posk@posk.io>,
"Alexander Mikhalitsyn" <alexander@mihalicyn.com>,
"Chris Kennelly" <ckennelly@google.com>,
"Ingo Molnar" <mingo@redhat.com>,
"Darren Hart" <dvhart@infradead.org>,
"Andr� Almeida" <andrealmeid@igalia.com>,
libc-alpha@sourceware.org, "Steven Rostedt" <rostedt@goodmis.org>,
"Jonathan Corbet" <corbet@lwn.net>,
longman@redhat.com
Subject: Re: [RFC PATCH 0/4] Extend rseq with sched_state field
Date: Wed, 17 May 2023 09:07:56 -0700 [thread overview]
Message-ID: <a5x2hd6yx55fqtlfhoke4ofvsua5sddmqvi5fd5xuh4uuoo676@nffuciys4zcm> (raw)
In-Reply-To: <20230517152654.7193-1-mathieu.desnoyers@efficios.com>
+Cc Waiman.
On Wed, 17 May 2023, Mathieu Desnoyers wrote:
>This prototype extends struct rseq with a new sched_state field, which
>contains a "on-cpu" flag kept up-to-date by the scheduler.
>
>It is meant to be used by userspace adaptative mutexes to decide between
>busy-wait and futex wait system call (releasing the CPU) behaviors based
>on the current state of the mutex owner.
>
>The goal is to improve use-cases where the duration of the critical
>sections for a given lock follows a multi-modal distribution, preventing
>statistical guesses from doing a good job at choosing between busy-wait
>and futex wait behavior.
>
>This is in response to the LWN coverage of 2023 Open Source Summit North
>America (https://lwn.net/Articles/931789/) unscheduled slot "Adaptive
>spinning in user space" presented by André Almeida.
>
>Feedback is welcome!
>
>Mathieu
>
>Mathieu Desnoyers (4):
> rseq: Add sched_state field to struct rseq
> selftests/rseq: Add sched_state rseq field and getter
> selftests/rseq: Implement sched state test program
> selftests/rseq: Implement rseq_mutex test program
>
> include/linux/sched.h | 12 ++
> include/uapi/linux/rseq.h | 17 +++
> kernel/rseq.c | 14 ++
> tools/testing/selftests/rseq/.gitignore | 2 +
> tools/testing/selftests/rseq/Makefile | 3 +-
> tools/testing/selftests/rseq/rseq-abi.h | 17 +++
> tools/testing/selftests/rseq/rseq.h | 5 +
> tools/testing/selftests/rseq/rseq_mutex.c | 120 ++++++++++++++++++
> .../testing/selftests/rseq/sched_state_test.c | 71 +++++++++++
> 9 files changed, 260 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/rseq/rseq_mutex.c
> create mode 100644 tools/testing/selftests/rseq/sched_state_test.c
>
>--
>2.25.1
>
next prev parent reply other threads:[~2023-05-17 16:41 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 15:26 [RFC PATCH 0/4] Extend rseq with sched_state field Mathieu Desnoyers
2023-05-17 15:26 ` [RFC PATCH 1/4] rseq: Add sched_state field to struct rseq Mathieu Desnoyers
2023-05-17 16:03 ` Davidlohr Bueso
2023-05-18 21:49 ` Boqun Feng
2023-05-19 14:15 ` Mathieu Desnoyers
2023-05-19 17:18 ` Boqun Feng
2023-05-23 14:10 ` Mathieu Desnoyers
2023-05-19 20:51 ` Noah Goldstein
2023-05-23 12:49 ` Mathieu Desnoyers
2023-05-23 16:32 ` Noah Goldstein
2023-05-23 17:30 ` Mathieu Desnoyers
2023-05-23 20:10 ` Noah Goldstein
2023-05-17 15:26 ` [RFC PATCH 2/4] selftests/rseq: Add sched_state rseq field and getter Mathieu Desnoyers
2023-05-28 14:04 ` kernel test robot
2023-05-17 15:26 ` [RFC PATCH 3/4] selftests/rseq: Implement sched state test program Mathieu Desnoyers
2023-05-17 15:26 ` [RFC PATCH 4/4] selftests/rseq: Implement rseq_mutex " Mathieu Desnoyers
2023-05-17 16:07 ` Davidlohr Bueso [this message]
2023-05-17 18:36 ` [RFC PATCH 0/4] Extend rseq with sched_state field Steven Rostedt
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