From: john cooper <john.cooper@timesys.com>
To: Esben Nielsen <simlo@phys.au.dk>
Cc: Mark_H_Johnson@raytheon.com,
Florian Schmidt <mista.tapas@gmx.net>,
Amit Shah <amit.shah@codito.com>,
Karsten Wiese <annabellesgarden@yahoo.de>,
Bill Huey <bhuey@lnxw.com>, Adam Heath <doogie@debian.org>,
emann@mrv.com, Gunther Persoons <gunther_persoons@spymac.com>,
"K.R. Foley" <kr@cybsft.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Fernando Pablo Lopez-Lezcano <nando@ccrma.Stanford.EDU>,
Lee Revell <rlrevell@joe-job.com>,
Rui Nuno Capela <rncbc@rncbc.org>,
Shane Shrybman <shrybman@aei.ca>,
Thomas Gleixner <tglx@linutronix.de>,
Michal Schmidt <xschmi00@stud.feec.vutbr.cz>,
john cooper <john.cooper@timesys.com>
Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6
Date: Thu, 09 Dec 2004 14:58:45 -0500 [thread overview]
Message-ID: <41B8AE75.2090905@timesys.com> (raw)
In-Reply-To: <Pine.OSF.4.05.10412091907430.4626-100000@da410.ifa.au.dk>
Esben Nielsen wrote:
> Muteces are also an overhead. There must be a lot of locks in the system
> which can safely be transfered back to raw spinlocks as the locking time
> is in the same order of the locking time internally in a mutex. There is
> no perpose of using a mutex instead of a raw spinlock if the region being
> locked is shorter or about the same as the job of handling the mutex
> internals and rescheduling (twice)!
That will certainly be the case in some scenarios. It seems
useful for the mutex user to have a means to advice of the
anticipated usage (hold time).
The other [perhaps additional] means of adaptation would be
Solaris-style where a failed mutex acquisition attempt would
spin rather than block the caller if the mutex owner is
currently running on some other cpu. The rationale being the
spin wait time is less overhead compared with two context
switches. Though I'd expect this ideal has been batted around
here before.
-john
--
john.cooper@timesys.com
next prev parent reply other threads:[~2004-12-09 20:01 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-09 16:56 [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6 Mark_H_Johnson
2004-12-09 17:28 ` Ingo Molnar
2004-12-09 17:41 ` Ingo Molnar
2004-12-09 18:26 ` Ingo Molnar
2004-12-09 19:04 ` Esben Nielsen
2004-12-09 19:58 ` john cooper [this message]
2004-12-09 20:16 ` Lee Revell
-- strict thread matches above, loose matches on Subject: below --
2004-12-13 14:10 Mark_H_Johnson
2004-12-09 21:58 Mark_H_Johnson
2004-12-09 22:55 ` Ingo Molnar
2004-12-09 20:49 Mark_H_Johnson
2004-12-09 21:56 ` Ingo Molnar
2004-12-09 20:38 Mark_H_Johnson
2004-12-09 19:54 Mark_H_Johnson
2004-12-09 19:23 Mark_H_Johnson
2004-12-09 20:04 ` Ingo Molnar
2004-12-10 5:01 ` Bill Huey
2004-12-10 5:14 ` Steven Rostedt
2004-12-10 5:58 ` Bill Huey
2004-12-09 18:15 Mark_H_Johnson
2004-12-09 20:11 ` Ingo Molnar
2004-12-09 18:10 Mark_H_Johnson
2004-12-09 19:40 ` Ingo Molnar
2004-12-09 19:58 ` Ingo Molnar
2004-12-10 23:42 ` Steven Rostedt
2004-12-11 16:59 ` john cooper
2004-12-12 4:36 ` Steven Rostedt
2004-12-13 23:45 ` john cooper
2004-12-14 13:01 ` Steven Rostedt
2004-12-14 14:28 ` john cooper
2004-12-14 16:53 ` Steven Rostedt
2004-12-11 17:59 ` Esben Nielsen
2004-12-11 18:59 ` Steven Rostedt
2004-12-11 19:50 ` Esben Nielsen
2004-12-11 22:34 ` Steven Rostedt
2004-12-13 21:55 ` Bill Huey
2004-12-13 22:15 ` Steven Rostedt
2004-12-13 22:20 ` Ingo Molnar
2004-12-13 22:31 ` Ingo Molnar
2004-12-09 17:22 Mark_H_Johnson
2004-12-09 17:31 ` Ingo Molnar
2004-12-09 20:34 ` K.R. Foley
2004-12-09 22:06 ` Ingo Molnar
2004-12-09 23:16 ` K.R. Foley
2004-12-10 4:26 ` K.R. Foley
2004-12-10 11:22 ` Ingo Molnar
2004-12-10 15:26 ` K.R. Foley
2004-12-09 15:16 Mark_H_Johnson
2004-12-09 16:17 ` Florian Schmidt
2004-12-09 17:13 ` Ingo Molnar
2004-12-09 14:46 Mark_H_Johnson
2004-12-09 14:14 Mark_H_Johnson
2004-12-07 21:41 Mark_H_Johnson
2004-11-16 13:09 [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm1-V0.7.27-1 Ingo Molnar
2004-11-16 13:40 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm1-V0.7.27-3 Ingo Molnar
2004-11-17 12:42 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm1-V0.7.28-0 Ingo Molnar
2004-11-18 12:35 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm1-V0.7.28-1 Ingo Molnar
2004-11-18 16:46 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.29-0 Ingo Molnar
2004-11-22 0:54 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.30-2 Ingo Molnar
2004-11-23 17:58 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.30-9 Ingo Molnar
2004-11-24 10:16 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.30-10 Ingo Molnar
2004-12-03 20:58 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.32-0 Ingo Molnar
2004-12-07 13:29 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-4 Ingo Molnar
2004-12-07 14:11 ` [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6 Ingo Molnar
2004-12-08 4:31 ` K.R. Foley
2004-12-08 8:34 ` Ingo Molnar
2004-12-08 16:07 ` K.R. Foley
2004-12-08 16:18 ` Lee Revell
2004-12-08 16:52 ` K.R. Foley
2004-12-08 16:58 ` Lee Revell
2004-12-09 9:02 ` Ingo Molnar
2004-12-09 2:45 ` K.R. Foley
2004-12-09 12:11 ` Ingo Molnar
2004-12-09 14:50 ` K.R. Foley
2004-12-08 17:13 ` Steven Rostedt
2004-12-08 18:14 ` Rui Nuno Capela
2004-12-08 19:03 ` Steven Rostedt
2004-12-08 21:39 ` Rui Nuno Capela
2004-12-08 22:11 ` Steven Rostedt
2004-12-09 9:32 ` Ingo Molnar
2004-12-09 13:36 ` Steven Rostedt
2004-12-09 9:06 ` Ingo Molnar
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