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Date:   Thu, 14 Jun 2018 15:49:59 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     Florian Weimer <fweimer@redhat.com>, carlos <carlos@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        libc-alpha <libc-alpha@sourceware.org>
Subject: Re: Restartable Sequences system call merged into Linux
Message-ID: <20180614134959.GA4084@amd>
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Hi!

> >> - rseq_preempt(): on preemption, the scheduler sets the TIF_NOTIFY_RES=
UME thread
> >>   flag, so rseq_handle_notify_resume() can check whether it's in a rse=
q critical
> >>   section when returning to user-space,
> >> - rseq_signal_deliver(): on signal delivery, rseq_handle_notify_resume=
() checks
> >>   whether it's in a rseq critical section,
> >> - rseq_migrate: on migration, the scheduler sets TIF_NOTIFY_RESUME as =
well,
> >=20
> > Yes, this is not likely to be noticeable.
> >=20
> > But the proposal wanted to add a syscall to thread creation, right?
> > And I believe that may be noticeable.
>=20
> Fair point! Do we have a standard benchmark that would stress this ?

Web server performance benchmarks basically test clone() performance
in many cases.
									Pavel

--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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