From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Colascione <dancol@google.com>
Cc: mathieu.desnoyers@efficios.com, paulmck@linux.vnet.ibm.com,
boqun.feng@gmail.com, luto@amacapital.net, davejwatson@fb.com,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
pjt@google.com, Andrew Morton <akpm@linux-foundation.org>,
linux@arm.linux.org.uk, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, Andrew Hunter <ahh@google.com>,
andi@firstfloor.org, cl@linux.com, bmaurer@fb.com,
rostedt@goodmis.org, josh@joshtriplett.org,
torvalds@linux-foundation.org, catalin.marinas@arm.com,
will.deacon@arm.com, mtk.manpages@gmail.com,
Joel Fernandes <joelaf@google.com>
Subject: Re: [RFC PATCH for 4.18 00/14] Restartable Sequences
Date: Wed, 2 May 2018 10:43:28 +0200 [thread overview]
Message-ID: <20180502084328.GE12180@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKOZuesa338sc_=w6-wvro25idrSN_zx_zrHFyo-bDiORs7FZw@mail.gmail.com>
On Wed, May 02, 2018 at 03:53:47AM +0000, Daniel Colascione wrote:
> The usual approach to "better" is an "adaptive mutex". Such a thing, when
> it attempts to acquire a lock another thread owns, spins for some number of
> iterations, then falls back to futex. I guess that's a little better than
> immediately jumping to futex, but it's not optimal. We can still spin when
> the lock owner isn't scheduled, and the spin count is usually some guess
> (either specified manually or estimated statistically) that's not
> guaranteed to produce decent results. Even if we do pick a good spin count,
> we run a very good chance of under- or over-spinning on any given
> lock-acquire. We always want to sleep when spinning would be pointless.
Look for the FUTEX_LOCK patches from Waiman.
next prev parent reply other threads:[~2018-05-02 8:44 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-30 22:44 Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 01/14] uapi headers: Provide types_32_64.h (v2) Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 02/14] rseq: Introduce restartable sequences system call (v13) Mathieu Desnoyers
2018-05-16 16:24 ` Peter Zijlstra
2018-05-16 20:18 ` Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 03/14] arm: Add restartable sequences support Mathieu Desnoyers
2018-05-16 16:18 ` Peter Zijlstra
2018-05-16 20:13 ` Mathieu Desnoyers
2018-05-17 13:32 ` Will Deacon
2018-05-17 15:30 ` Mathieu Desnoyers
2018-05-22 18:19 ` Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 04/14] arm: Wire up restartable sequences system call Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 05/14] x86: Add support for restartable sequences (v2) Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 06/14] x86: Wire up restartable sequence system call Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 07/14] powerpc: Add support for restartable sequences Mathieu Desnoyers
2018-05-16 16:18 ` Peter Zijlstra
2018-05-16 20:13 ` Mathieu Desnoyers
2018-05-17 1:19 ` Boqun Feng
2018-05-17 7:43 ` Peter Zijlstra
2018-05-17 15:28 ` Mathieu Desnoyers
2018-05-17 23:50 ` Boqun Feng
2018-05-18 18:17 ` Mathieu Desnoyers
2018-05-20 14:08 ` Boqun Feng
2018-05-23 20:14 ` Mathieu Desnoyers
2018-05-23 20:46 ` Paul E. McKenney
2018-05-23 21:29 ` Mathieu Desnoyers
2018-05-24 1:03 ` Michael Ellerman
2018-05-28 7:00 ` Mathieu Desnoyers
2018-05-18 12:38 ` Michael Ellerman
2018-04-30 22:44 ` [PATCH 08/14] powerpc: Wire up restartable sequences system call Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 09/14] selftests: lib.mk: Introduce OVERRIDE_TARGETS Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 10/14] rseq: selftests: Provide rseq library (v5) Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 11/14] rseq: selftests: Provide basic test Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 12/14] rseq: selftests: Provide basic percpu ops test (v2) Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 13/14] rseq: selftests: Provide parametrized tests (v2) Mathieu Desnoyers
2018-04-30 22:44 ` [PATCH 14/14] rseq: selftests: Provide Makefile, scripts, gitignore (v2) Mathieu Desnoyers
2018-05-02 3:53 ` [RFC PATCH for 4.18 00/14] Restartable Sequences Daniel Colascione
2018-05-02 8:43 ` Peter Zijlstra [this message]
2018-05-02 16:03 ` Mathieu Desnoyers
2018-05-02 16:07 ` Daniel Colascione
2018-05-02 16:42 ` Steven Rostedt
2018-05-02 16:55 ` Daniel Colascione
2018-05-03 16:12 ` Mathieu Desnoyers
2018-05-03 16:22 ` Daniel Colascione
2018-05-03 18:04 ` Mathieu Desnoyers
2018-05-03 16:48 ` Joel Fernandes
2018-05-03 17:18 ` Daniel Colascione
2018-05-03 17:46 ` Joel Fernandes
2018-05-04 22:17 ` Ben Maurer
2018-05-02 17:22 ` Peter Zijlstra
2018-05-02 18:27 ` Daniel Colascione
2018-05-02 20:22 ` Peter Zijlstra
2018-05-02 20:37 ` Daniel Colascione
2018-05-03 1:15 ` Steven Rostedt
2018-05-03 8:49 ` Peter Zijlstra
2018-05-06 10:03 ` Thomas Gleixner
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