From: Waiman Long <waiman.long@hpe.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Peter Zijlstra <peterz@infradead.org>,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Ingo Molnar <mingo@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
<linux-kernel@vger.kernel.org>, <linux-doc@vger.kernel.org>,
Jason Low <jason.low2@hpe.com>,
Scott J Norton <scott.norton@hpe.com>,
Douglas Hatch <doug.hatch@hpe.com>
Subject: Re: [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes
Date: Thu, 22 Sep 2016 17:59:20 -0400 [thread overview]
Message-ID: <57E45438.2010307@hpe.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1609222339180.5640@nanos>
On 09/22/2016 05:41 PM, Thomas Gleixner wrote:
> On Thu, 22 Sep 2016, Davidlohr Bueso wrote:
>> On Thu, 22 Sep 2016, Waiman Long wrote:
>>
>>> BTW, my initial attempt for the new futex was to use the same workflow as
>>> the PI futexes, but use mutex which has optimistic spinning instead of
>>> rt_mutex.
>> Btw, Thomas, do you still have any interest pursuing this for rtmutexes from
>> -rt into mainline? If so I can resend the patches from a while ago.
> Certainly yes. My faint memory tells me that there was some potential issue
> due to boosting the owner only if it gets scheduled out, but I might be
> wrong.
It is tricky to add optimistic spinning to rtmutexes because of the need
to observe process priorities. It is certainly possible to make the top
waiter spin, but then I am not sure how much performance gain with just
that.
Cheers,
Longman
next prev parent reply other threads:[~2016-09-22 22:00 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-20 13:42 [RFC PATCH v2 0/5] futex: Introducing throughput-optimized futexes Waiman Long
2016-09-20 13:42 ` [RFC PATCH v2 1/5] futex: Add futex_set_timer() helper function Waiman Long
2016-09-22 21:31 ` Thomas Gleixner
2016-09-23 0:45 ` Waiman Long
2016-09-20 13:42 ` [RFC PATCH v2 2/5] futex: Rename futex_pi_state to futex_state Waiman Long
2016-09-20 13:42 ` [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes Waiman Long
2016-09-21 6:59 ` Mike Galbraith
2016-09-21 23:37 ` Waiman Long
2016-09-22 7:49 ` Peter Zijlstra
2016-09-22 13:04 ` Waiman Long
2016-09-22 13:34 ` Thomas Gleixner
2016-09-22 14:41 ` Davidlohr Bueso
2016-09-22 14:46 ` Thomas Gleixner
2016-09-22 15:11 ` Davidlohr Bueso
2016-09-22 20:08 ` Waiman Long
2016-09-22 20:28 ` Waiman Long
2016-09-22 20:38 ` Thomas Gleixner
2016-09-22 21:48 ` Waiman Long
2016-09-23 13:02 ` Thomas Gleixner
2016-09-26 22:02 ` Waiman Long
2016-09-22 21:39 ` Davidlohr Bueso
2016-09-22 21:41 ` Thomas Gleixner
2016-09-22 21:59 ` Waiman Long [this message]
2016-09-27 19:02 ` [PATCH v2 -tip] locking/rtmutex: Reduce top-waiter blocking on a lock Davidlohr Bueso
2016-10-24 18:08 ` Davidlohr Bueso
2016-10-24 18:48 ` Thomas Gleixner
2016-09-24 1:28 ` [PATCH " Davidlohr Bueso
2016-09-26 21:40 ` Waiman Long
2016-09-22 19:56 ` [RFC PATCH v2 3/5] futex: Throughput-optimized (TO) futexes Waiman Long
2016-09-22 20:26 ` Thomas Gleixner
2016-09-22 21:13 ` Waiman Long
2016-09-22 13:23 ` Peter Zijlstra
2016-09-22 17:21 ` Waiman Long
2016-09-20 13:42 ` [RFC PATCH v2 4/5] futex: Add timeout support to TO futexes Waiman Long
2016-09-20 13:42 ` [RFC PATCH v2 5/5] futex, doc: TO futexes document Waiman Long
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