Problems with cyclictest and ps

Problems with cyclictest and ps

[Phil K.]

Hi,

I tried cyclictest under Debian Lenny with Kernel-2.6.23.8-hrt3 and
Kernel-2.6.22 as user root. As decribed on the cyclictest-wikipage all
cyclictest-tasks run with the scheduler class SCHED_FIFO. I controlled
the scheduler class with "ps -ce" and ps showed me SCHED_OTHER for the
cyclictest-task.

#> ./cyclictest -t 1 -p 80 -n -i 10000

#> ps -ce | grep cyclic
   PID CLS PRI TTY          TIME CMD
  9693 TS   19 pts/5    00:00:00 cyclictest

I am wondering why cyclictest runs as SCHED_OTHER I expected SCHED_FIFO
instead. Any explanations of this behavior are welcome.

Regards,

Phil

Re: Problems with cyclictest and ps

[K.R. Foley]

Phil K. wrote:
> Hi,
> 
> I tried cyclictest under Debian Lenny with Kernel-2.6.23.8-hrt3 and
> Kernel-2.6.22 as user root. As decribed on the cyclictest-wikipage all
> cyclictest-tasks run with the scheduler class SCHED_FIFO. I controlled
> the scheduler class with "ps -ce" and ps showed me SCHED_OTHER for the
> cyclictest-task.
> 
> #> ./cyclictest -t 1 -p 80 -n -i 10000
> 
> #> ps -ce | grep cyclic
>    PID CLS PRI TTY          TIME CMD
>   9693 TS   19 pts/5    00:00:00 cyclictest
> 
> I am wondering why cyclictest runs as SCHED_OTHER I expected SCHED_FIFO
> instead. Any explanations of this behavior are welcome.
> 
> Regards,
> 
> Phil
> -
> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

try "ps -eLc | grep cyclic"

Without the "L" you don't see threads/lightweight processes.

-- 
   kr

Re: Problems with cyclictest and ps

[Florian Boelstler]

Hi,

Phil K. wrote:
> I tried cyclictest under Debian Lenny with Kernel-2.6.23.8-hrt3 and
> Kernel-2.6.22 as user root. As decribed on the cyclictest-wikipage all
> cyclictest-tasks run with the scheduler class SCHED_FIFO. I controlled
> the scheduler class with "ps -ce" and ps showed me SCHED_OTHER for the
> cyclictest-task.

I had the same problem using 2.6.23.9-rt12 on Debian Etch
(schedutils-1.5.0-1) today. When checking the current state of
cyclictest with chrt (chrt -p <pid of cyclictest), it always reported
SCHED_OTHER and priority 0.
When I tried to change the scheduling policy and/or priority with chrt
it seemed to fail as well (not sure whether it tells the truth though).
On the other hand starting cyclictest via chrt did the trick:
"chrt -f 80 cyclictest..."

I can provide further details, when I am closer to the machine in
question tomorrow.

Cheers,

  Florian

Re: Problems with cyclictest and ps

[Phil K.]

K.R. Foley wrote:
> Phil K. wrote:
>> Hi,
>>
>> I tried cyclictest under Debian Lenny with Kernel-2.6.23.8-hrt3 and
>> Kernel-2.6.22 as user root. As decribed on the cyclictest-wikipage all
>> cyclictest-tasks run with the scheduler class SCHED_FIFO. I controlled
>> the scheduler class with "ps -ce" and ps showed me SCHED_OTHER for the
>> cyclictest-task.
>>
>> #> ./cyclictest -t 1 -p 80 -n -i 10000
>>
>> #> ps -ce | grep cyclic
>>    PID CLS PRI TTY          TIME CMD
>>   9693 TS   19 pts/5    00:00:00 cyclictest
>>
>> I am wondering why cyclictest runs as SCHED_OTHER I expected SCHED_FIFO
>> instead. Any explanations of this behavior are welcome.
>>
>> Regards,
>>
>> Phil
>> -
>> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> 
> try "ps -eLc | grep cyclic"
> 
> Without the "L" you don't see threads/lightweight processes.
> 

Thanks for the solution, I have postet this on the RTWiki
(http://rt.wiki.kernel.org/index.php/Cyclictest#FAQ).

Greetings,

Phil

Re: Problems with cyclictest and ps

[Phil K.]

Florian Boelstler wrote:
> Hi,
> 
> Phil K. wrote:
>> I tried cyclictest under Debian Lenny with Kernel-2.6.23.8-hrt3 and
>> Kernel-2.6.22 as user root. As decribed on the cyclictest-wikipage all
>> cyclictest-tasks run with the scheduler class SCHED_FIFO. I controlled
>> the scheduler class with "ps -ce" and ps showed me SCHED_OTHER for the
>> cyclictest-task.
> 
> I had the same problem using 2.6.23.9-rt12 on Debian Etch
> (schedutils-1.5.0-1) today. When checking the current state of
> cyclictest with chrt (chrt -p <pid of cyclictest), it always reported
> SCHED_OTHER and priority 0.
> When I tried to change the scheduling policy and/or priority with chrt
> it seemed to fail as well (not sure whether it tells the truth though).
> On the other hand starting cyclictest via chrt did the trick:
> "chrt -f 80 cyclictest..."
> 
> I can provide further details, when I am closer to the machine in
> question tomorrow.
> 
> Cheers,
> 
>   Florian

I posted the solution for that problem and described it in the
RTWiki(http://rt.wiki.kernel.org/index.php/Cyclictest#FAQ).

Greetings,

Phil

Re: Problems with cyclictest and ps

[Florian Boelstler]

Phil K. wrote:
> I posted the solution for that problem and described it in the
> RTWiki(http://rt.wiki.kernel.org/index.php/Cyclictest#FAQ).

Thanks for clarifying this rt-newbie issue.

Cheers,

   Florian