From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Waiman Long <Waiman.Long@hp.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Darren Hart <dvhart@linux.intel.com>,
Davidlohr Bueso <davidlohr@hp.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
linux-doc@vger.kernel.org, Jason Low <jason.low2@hp.com>,
Scott J Norton <scott.norton@hp.com>
Subject: Re: [RFC PATCH 0/5] futex: introduce an optimistic spinning futex
Date: Wed, 23 Jul 2014 08:57:36 +0200 [thread overview]
Message-ID: <20140723065736.GM3935@laptop> (raw)
In-Reply-To: <1406091303.5076.33.camel@marge.simpson.net>
On Wed, Jul 23, 2014 at 06:55:03AM +0200, Mike Galbraith wrote:
> On Mon, 2014-07-21 at 09:42 -0700, Andi Kleen wrote:
>
> > FWIW the main problem is currently that switch-through-idle is so
> > slow. I think improving that would give a boost to far more
> > situations.
>
> Two high frequency idle enter/exit suckage spots:
>
> 1) nohz (tick) - it's expensive to start/stop tick on every micro-idle,
> throttle it or something.
Yeah, so the idea was to use the cpuidle idle guestimator to control
this, and now that we've moved it somewhat closer to the scheduler that
might become possible.
> 2) ondemand governor - tweak silly default settings to reflect the
> reality that we routinely schedule communicating threads cross core.
Yeah, so the plan is to shoot cpufreq in the head and base the
replacement on smp aware metrics ;-) Its on a todo list somewhere..
next prev parent reply other threads:[~2014-07-23 6:57 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-21 15:24 [RFC PATCH 0/5] futex: introduce an optimistic spinning futex Waiman Long
2014-07-21 15:24 ` [RFC PATCH 1/5] futex: add new exclusive lock & unlock command codes Waiman Long
2014-07-21 16:42 ` Thomas Gleixner
2014-07-22 18:22 ` Waiman Long
[not found] ` <53CEABD7.3030509-VXdhtT5mjnY@public.gmane.org>
2014-07-22 21:00 ` Thomas Gleixner
[not found] ` <1405956271-34339-1-git-send-email-Waiman.Long-VXdhtT5mjnY@public.gmane.org>
2014-07-21 15:24 ` [RFC PATCH 2/5] futex: add optimistic spinning to FUTEX_SPIN_LOCK Waiman Long
[not found] ` <1405956271-34339-3-git-send-email-Waiman.Long-VXdhtT5mjnY@public.gmane.org>
2014-07-21 17:15 ` Davidlohr Bueso
[not found] ` <1405962929.11927.19.camel-5JQ4ckphU/8SZAcGdq5asR6epYMZPwEe5NbjCUgZEJk@public.gmane.org>
2014-07-22 18:46 ` Waiman Long
2014-07-21 20:17 ` Jason Low
2014-07-22 19:34 ` Waiman Long
2014-07-21 15:24 ` [RFC PATCH 3/5] spinning futex: move a wakened task to spinning Waiman Long
2014-07-21 15:24 ` [RFC PATCH 4/5] spinning futex: put waiting tasks in a sorted rbtree Waiman Long
2014-07-21 15:24 ` [RFC PATCH 5/5] futex, doc: add a document on how to use the spinning futexes Waiman Long
2014-07-21 15:45 ` Randy Dunlap
2014-07-22 3:19 ` Waiman Long
2014-07-21 16:42 ` [RFC PATCH 0/5] futex: introduce an optimistic spinning futex Andi Kleen
2014-07-21 16:45 ` Andi Kleen
[not found] ` <871tte3bjw.fsf-KWJ+5VKanrL29G5dvP0v1laTQe2KTcn/@public.gmane.org>
2014-07-21 17:20 ` Darren Hart
[not found] ` <CFF29A00.9D44A%dvhart@linux.intel.com>
[not found] ` <CFF29A00.9D44A%dvhart-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2014-07-21 17:41 ` Darren Hart
[not found] ` <CFF29E4A.9D44E%dvhart-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2014-07-21 20:16 ` Thomas Gleixner
2014-07-21 21:27 ` Peter Zijlstra
2014-07-21 21:31 ` Andy Lutomirski
2014-07-21 21:47 ` Thomas Gleixner
2014-07-21 22:41 ` Darren Hart
2014-07-22 1:01 ` Thomas Gleixner
2014-07-22 1:34 ` Steven Rostedt
2014-07-22 2:31 ` Mike Galbraith
2014-07-22 3:06 ` Davidlohr Bueso
[not found] ` <20140721213457.46623e2f-f9ZlEuEWxVcJvu8Pb33WZ0EMvNT87kid@public.gmane.org>
2014-07-22 7:47 ` Peter Zijlstra
2014-07-22 8:39 ` Thomas Gleixner
2014-07-22 8:48 ` Peter Zijlstra
2014-07-22 9:59 ` Thomas Gleixner
2014-07-22 20:25 ` Waiman Long
2014-07-22 20:52 ` Thomas Gleixner
2014-07-22 20:21 ` Waiman Long
2014-07-22 21:03 ` Thomas Gleixner
2014-07-22 0:32 ` Davidlohr Bueso
2014-07-22 7:35 ` Peter Zijlstra
2014-07-21 21:43 ` Thomas Gleixner
2014-07-21 18:24 ` Thomas Gleixner
2014-07-22 18:35 ` Waiman Long
2014-07-22 18:28 ` Waiman Long
[not found] ` <8761iq3bp3.fsf-KWJ+5VKanrL29G5dvP0v1laTQe2KTcn/@public.gmane.org>
2014-07-23 4:55 ` Mike Galbraith
2014-07-23 6:57 ` Peter Zijlstra [this message]
2014-07-23 7:25 ` Mike Galbraith
2014-07-23 7:35 ` Peter Zijlstra
2014-07-23 7:39 ` Mike Galbraith
2014-07-23 7:52 ` Peter Zijlstra
2014-07-21 21:18 ` Ingo Molnar
2014-07-21 21:41 ` Thomas Gleixner
[not found] ` <20140721211801.GA12149-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-07-22 19:36 ` Waiman Long
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