* Re: [Xenomai-help] Time between ISR and RT Task
@ 2006-08-04 7:08 GSM909
2006-08-04 13:27 ` Gilles Chanteperdrix
0 siblings, 1 reply; 6+ messages in thread
From: GSM909 @ 2006-08-04 7:08 UTC (permalink / raw)
To: gilles.chanteperdrix; +Cc: xenomai
GSM909@domain.hid wrote:
> Hello
>
> I have run a few programs with Xenomai tasks and have no problems. But I notice that the time between ISR and RT task ( RT task is suspended and resumed by the ISR) is shorter when Linux have a lot of work ( average load around 10 ) as when Linux has nothing to do( al : 0.05 ).
Do you observe this for worst case, or for average case latencies? Do you observe this when you boot with the idle=poll parameter ?
When idle, Linux uses the 'hlt' instruction, that stops the CPU until an interrupt happen, maybe waking up from this state take a little bit more time than when an interrupt is received directly?
How can I set idel = poll ?
and what are other options for idel ?
Regards
Ted
--
Gilles Chanteperdrix.
--
Echte DSL-Flatrate dauerhaft für 0,- Euro*. Nur noch kurze Zeit!
"Feel free" mit GMX DSL: http://www.gmx.net/de/go/dsl
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xenomai-help] Time between ISR and RT Task
2006-08-04 7:08 [Xenomai-help] Time between ISR and RT Task GSM909
@ 2006-08-04 13:27 ` Gilles Chanteperdrix
2006-08-04 18:52 ` newsletter
0 siblings, 1 reply; 6+ messages in thread
From: Gilles Chanteperdrix @ 2006-08-04 13:27 UTC (permalink / raw)
To: GSM909; +Cc: xenomai
GSM909@domain.hid wrote:
> GSM909@domain.hid wrote:
> > Hello
> >
> > I have run a few programs with Xenomai tasks and have no problems. But I notice that the time between ISR and RT task ( RT task is suspended and resumed by the ISR) is shorter when Linux have a lot of work ( average load around 10 ) as when Linux has nothing to do( al : 0.05 ).
>
> Do you observe this for worst case, or for average case latencies? Do you observe this when you boot with the idle=poll parameter ?
>
> When idle, Linux uses the 'hlt' instruction, that stops the CPU until an interrupt happen, maybe waking up from this state take a little bit more time than when an interrupt is received directly?
>
> How can I set idel = poll ?
That's idle, not idel. The way to pass this option to the kernel depend
on the bootloader you are using. If using lilo on x86, add a line:
append="idle=poll"
to the /etc/lilo.conf section for the image you are booting (if there is
already an "append" line, then add "idle=poll" to this line)
If using grub on x86, add idle=poll to the /boot/grub/menu.lst line
beginning with "kernel" for the xenomai kernel.
Anyway, you should let the latency test run a few hours for a given
configuration before concluding anything, the worst case latency does
not show up so easily.
--
Gilles Chanteperdrix.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xenomai-help] Time between ISR and RT Task
2006-08-04 13:27 ` Gilles Chanteperdrix
@ 2006-08-04 18:52 ` newsletter
2006-08-12 19:35 ` Gilles Chanteperdrix
0 siblings, 1 reply; 6+ messages in thread
From: newsletter @ 2006-08-04 18:52 UTC (permalink / raw)
To: Gilles Chanteperdrix; +Cc: xenomai
Sorry
My System:
MPC8270 (PowerPC)
with uboot
Denx Linux und Xenomai Realtime Framework :)
thx for Helping
Gilles Chanteperdrix wrote:
> GSM909@domain.hid wrote:
> > GSM909@domain.hid wrote:
> > > Hello
> > >
> > > I have run a few programs with Xenomai tasks and have no problems. But I notice that the time between ISR and RT task ( RT task is suspended and resumed by the ISR) is shorter when Linux have a lot of work ( average load around 10 ) as when Linux has nothing to do( al : 0.05 ).
> >
> > Do you observe this for worst case, or for average case latencies? Do you observe this when you boot with the idle=poll parameter ?
> >
> > When idle, Linux uses the 'hlt' instruction, that stops the CPU until an interrupt happen, maybe waking up from this state take a little bit more time than when an interrupt is received directly?
> >
> > How can I set idel = poll ?
>
> That's idle, not idel. The way to pass this option to the kernel depend
> on the bootloader you are using. If using lilo on x86, add a line:
>
> append="idle=poll"
>
> to the /etc/lilo.conf section for the image you are booting (if there is
> already an "append" line, then add "idle=poll" to this line)
>
> If using grub on x86, add idle=poll to the /boot/grub/menu.lst line
> beginning with "kernel" for the xenomai kernel.
>
> Anyway, you should let the latency test run a few hours for a given
> configuration before concluding anything, the worst case latency does
> not show up so easily.
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Xenomai-help] Time between ISR and RT Task
@ 2006-08-03 13:35 GSM909
2006-08-03 17:36 ` Gilles Chanteperdrix
0 siblings, 1 reply; 6+ messages in thread
From: GSM909 @ 2006-08-03 13:35 UTC (permalink / raw)
To: xenomai
Hello
I have run a few programs with Xenomai tasks and have no problems. But I notice that the time between ISR and RT task ( RT task is suspended and resumed by the ISR) is shorter when Linux have a lot of work ( average load around 10 ) as when Linux has nothing to do( al : 0.05 ).
My simple Question is why ?? :)
thx
Ted
--
Echte DSL-Flatrate dauerhaft für 0,- Euro*. Nur noch kurze Zeit!
"Feel free" mit GMX DSL: http://www.gmx.net/de/go/dsl
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xenomai-help] Time between ISR and RT Task
2006-08-03 13:35 GSM909
@ 2006-08-03 17:36 ` Gilles Chanteperdrix
0 siblings, 0 replies; 6+ messages in thread
From: Gilles Chanteperdrix @ 2006-08-03 17:36 UTC (permalink / raw)
To: GSM909; +Cc: xenomai
GSM909@domain.hid wrote:
> Hello
>
> I have run a few programs with Xenomai tasks and have no problems. But I notice that the time between ISR and RT task ( RT task is suspended and resumed by the ISR) is shorter when Linux have a lot of work ( average load around 10 ) as when Linux has nothing to do( al : 0.05 ).
Do you observe this for worst case, or for average case latencies? Do
you observe this when you boot with the idle=poll parameter ?
When idle, Linux uses the 'hlt' instruction, that stops the CPU until an
interrupt happen, maybe waking up from this state take a little bit more
time than when an interrupt is received directly?
--
Gilles Chanteperdrix.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2006-08-12 19:35 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2006-08-04 7:08 [Xenomai-help] Time between ISR and RT Task GSM909
2006-08-04 13:27 ` Gilles Chanteperdrix
2006-08-04 18:52 ` newsletter
2006-08-12 19:35 ` Gilles Chanteperdrix
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2006-08-03 13:35 GSM909
2006-08-03 17:36 ` Gilles Chanteperdrix
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