From: Peter Zijlstra <peterz@infradead.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
Tony Lindgren <tony@atomide.com>, Mike Galbraith <efault@gmx.de>
Subject: Re: [RFC PATCH 00/11] sched: CFS low-latency features
Date: Fri, 27 Aug 2010 19:27:52 +0200 [thread overview]
Message-ID: <1282930072.1975.2962.camel@laptop> (raw)
In-Reply-To: <20100827160946.GG14926@Krystal>
On Fri, 2010-08-27 at 12:09 -0400, Mathieu Desnoyers wrote:
> > The specification also doesn't cover the case where the handler takes
> > more time to execute than the timer interval.
>
> Why should it ? It seems valid for a workload to result in spawning many threads
> bound to more than a single core on a multi-core system. So concurrency
> management should be performed by the application.
The problem with allowing concurrency is that the moment you want to do
that you get the spawner context and error propagation problems.
Thus we're limited to spawning a single thread at timer_create() and
handling expirations in there. At that point you have to specify what
happens to an expiration while the handler is running, will it queue
handlers or will you have to carefully craft your handler using
timer_getoverrun().
But I really don't understand why POSIX would provide this composite
functionality instead of providing the separate bits to implement this,
which I think is only SIGEV_THREAD_ID which is missing.
next prev parent reply other threads:[~2010-08-27 17:28 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-26 18:09 [RFC PATCH 00/11] sched: CFS low-latency features Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 01/11] sched: fix string comparison in features Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 02/11] sched: debug spread check account for nr_running Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 03/11] sched: FAIR_SLEEPERS feature Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 04/11] sched: debug cleanup place entity Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 05/11] sched buddy enable buddy logic starting at 2 running threads Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 06/11] sched: dynamic min_vruntime Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 07/11] sched rename struct task in_iowait field to sched_in_iowait Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 08/11] sched input interactivity-driven next buddy Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 09/11] sched: timer-driven " Mathieu Desnoyers
2010-08-27 18:02 ` [RFC PATCH 09/11] sched: timer-driven next buddy (update) Mathieu Desnoyers
2010-08-27 18:14 ` Thomas Gleixner
2010-08-26 18:09 ` [RFC PATCH 10/11] sched: fork expedited Mathieu Desnoyers
2010-08-26 18:09 ` [RFC PATCH 11/11] sched: fair sleepers for timer and interactive Mathieu Desnoyers
2010-08-26 18:57 ` [RFC PATCH 00/11] sched: CFS low-latency features Peter Zijlstra
2010-08-26 21:25 ` Thomas Gleixner
2010-08-26 22:22 ` Thomas Gleixner
2010-08-26 23:09 ` Mathieu Desnoyers
2010-08-26 23:36 ` Mathieu Desnoyers
2010-08-27 7:38 ` Peter Zijlstra
2010-08-27 15:23 ` Mathieu Desnoyers
2010-08-27 8:43 ` Thomas Gleixner
2010-08-27 15:50 ` Mathieu Desnoyers
2010-08-27 7:37 ` Peter Zijlstra
2010-08-27 15:21 ` Mathieu Desnoyers
2010-08-27 15:41 ` Peter Zijlstra
2010-08-27 16:09 ` Mathieu Desnoyers
2010-08-27 17:27 ` Peter Zijlstra [this message]
2010-08-27 18:32 ` Mathieu Desnoyers
2010-08-27 19:23 ` Peter Zijlstra
2010-08-27 19:57 ` Mathieu Desnoyers
2010-08-31 15:02 ` Mathieu Desnoyers
2010-08-26 23:18 ` Paul E. McKenney
2010-08-26 23:28 ` Mathieu Desnoyers
2010-08-26 23:38 ` Paul E. McKenney
2010-08-26 23:53 ` Mathieu Desnoyers
2010-08-27 0:09 ` Paul E. McKenney
2010-08-27 15:18 ` Mathieu Desnoyers
2010-08-27 15:20 ` Thomas Gleixner
2010-08-27 15:30 ` Mathieu Desnoyers
2010-08-27 15:41 ` Peter Zijlstra
2010-08-26 23:49 ` Mathieu Desnoyers
2010-08-27 7:42 ` Peter Zijlstra
2010-08-27 8:19 ` Mike Galbraith
2010-08-27 15:43 ` Mathieu Desnoyers
2010-08-27 18:38 ` Mathieu Desnoyers
2010-08-28 7:33 ` Mike Galbraith
2010-08-27 10:47 ` Indan Zupancic
2010-08-27 10:58 ` Peter Zijlstra
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