From: Ingo Molnar <mingo@elte.hu>
To: Mark_H_Johnson@raytheon.com
Cc: 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,
Florian Schmidt <mista.tapas@gmx.net>,
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>,
Esben Nielsen <simlo@phys.au.dk>,
Thomas Gleixner <tglx@linutronix.de>,
Michal Schmidt <xschmi00@stud.feec.vutbr.cz>
Subject: Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6
Date: Thu, 9 Dec 2004 21:11:10 +0100 [thread overview]
Message-ID: <20041209201110.GB14194@elte.hu> (raw)
In-Reply-To: <OF005FDB8A.72F792AC-ON86256F65.0063E013@raytheon.com>
* Mark_H_Johnson@raytheon.com <Mark_H_Johnson@raytheon.com> wrote:
> >| The max CPU latencies in RT are worse than PK as well. The values for
> >| RT range from 3.00 msec to 5.43 msec and on PK range from 1.45 msec to
> >| 2.24 msec.
> >
> >
> >these come from userspace timestamping? So where userspace detects a
> >delay the kernel tracer doesnt measure any?
>
> Yes. That is correct. Very puzzling to me too.
well, i think this measurement issue needs resolving before jumping to
any generic conclusions. Not a single trace is extremely suspect. The
userspace timestamps are rdtsc based, or gettimeofday() based? In
theory, as long as no trace is triggered, there should not be any huge
overhead from tracing itself (when a trace is reported and saved then,
if the trace is large, it can be quite expensive that the tracer wont
report as a latency - but this isnt the case here).
Ingo
next prev parent reply other threads:[~2004-12-09 20:11 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-09 18:15 [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-6 Mark_H_Johnson
2004-12-09 20:11 ` Ingo Molnar [this message]
-- 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 18:10 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 16:56 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
2004-12-09 20:16 ` Lee Revell
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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