[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <a5x2hd6yx55fqtlfhoke4ofvsua5sddmqvi5fd5xuh4uuoo676@nffuciys4zcm>
Date: Wed, 17 May 2023 09:07:56 -0700
From: Davidlohr Bueso <dave@...olabs.net>
To: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Peter Zijlstra <peterz@...radead.org>,
linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
"Paul E . McKenney" <paulmck@...nel.org>,
Boqun Feng <boqun.feng@...il.com>,
"H . Peter Anvin" <hpa@...or.com>, Paul Turner <pjt@...gle.com>,
linux-api@...r.kernel.org, Christian Brauner <brauner@...nel.org>,
Florian Weimer <fw@...eb.enyo.de>, David.Laight@...LAB.COM,
carlos@...hat.com, Peter Oskolkov <posk@...k.io>,
Alexander Mikhalitsyn <alexander@...alicyn.com>,
Chris Kennelly <ckennelly@...gle.com>,
Ingo Molnar <mingo@...hat.com>,
Darren Hart <dvhart@...radead.org>,
Andr� Almeida <andrealmeid@...lia.com>,
libc-alpha@...rceware.org, Steven Rostedt <rostedt@...dmis.org>,
Jonathan Corbet <corbet@....net>, longman@...hat.com
Subject: Re: [RFC PATCH 0/4] Extend rseq with sched_state field
+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
>
Powered by blists - more mailing lists