From: Armin Steinhoff <armin@steinhoff.de>
To: Carsten Emde <C.Emde@osadl.org>,
Patrik Lundquist <patrik.lundquist@gmail.com>
Cc: rt-users <linux-rt-users@vger.kernel.org>
Subject: Re: Operation not permitted / pthread_setschedparam
Date: Sat, 04 Oct 2014 14:36:04 +0200 [thread overview]
Message-ID: <542FE9B4.3060708@steinhoff.de> (raw)
In-Reply-To: <542FD0BE.10508@osadl.org>
Carsten Emde schrieb:
> Armin,
>
>> [..] But there are some sideeffects to other running
>> processes/threads related to their assigned priorities. Here is the
>> priority assignment after a fresh boot: ps -elf ->
>> Prio-After-OS-Restart.txt attached
>>
>> If the app "demo_mn_console" has started its first RT thread, a lot
>> of other processes/threads are jumping to the highest RT priority
>> 99!! Please have a look to: ps -elf -> Prio-after-app-start.txt
>>
>> Do we have a problem with the RT kernel ? Or is simply the ps
>> utility broken ?
> Let me try to summarize your observations and suspicions:
> 1. After booting your RT kernel, everything works as expected.
Yes, all seems to be OK.
> 2. The ps utility works as expected.
Yes
> 3. There are no bug reports that the RT kernel autonomously and at
> random fiddles around with task priorities.
I have submited a bug report in the meantime.
> 4. There are no bug reports that the ps utility - one of the most
> frequently used utilities - suddenly may start to display erroneous
> priority numbers.
A bug in the good old "ps" would be very unlikely.
>
> 5. At a given time, you start your application that apparently modifies
> task priorities *in some way*.
Not in some way ... the developers of the openPOWERLINK stack are using
plain POSIX calls.
> 6. Shortly afterwards you are observing that other not intended tasks
> changed their priority as well.
Yes ... most processes running previously at 80 are jumping to 99!
>
> 7. Your first suspicion is that we may have a problem with the RT kernel.
> 8. And your second suspicion is that the ps utility is broken.
The question about the operation of "ps" was just a formal one .. sorry.
>
> Doesn't come another suspicion to mind?
Why should I have one? The same code works correctly under then non-RT
version of the kernel ... at least from the Linux point of view.
--Armin
> -Carsten.
>
next prev parent reply other threads:[~2014-10-04 12:36 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-30 10:40 Operation not permitted / pthread_setschedparam Armin Steinhoff
2014-09-30 11:44 ` Harry van Haaren
2014-09-30 12:32 ` Armin Steinhoff
2014-09-30 17:22 ` Armin Steinhoff
2014-09-30 23:09 ` Thomas Gleixner
2014-10-01 7:27 ` Armin Steinhoff
2014-10-01 7:49 ` Patrik Lundquist
2014-10-02 8:02 ` Armin Steinhoff
2014-10-04 10:49 ` Carsten Emde
2014-10-04 12:36 ` Armin Steinhoff [this message]
2014-10-04 12:50 ` Armin Steinhoff
2014-10-04 23:56 ` Thomas Gleixner
2014-10-05 11:07 ` Armin Steinhoff
2014-10-05 11:47 ` Armin Steinhoff
2014-10-05 14:34 ` Armin Steinhoff
[not found] ` <54312C88.8060609@steinhoff.de>
2014-10-05 20:54 ` Thomas Gleixner
2014-10-06 8:03 ` Armin Steinhoff
2014-10-06 13:34 ` Armin Steinhoff
2014-10-07 1:33 ` Thomas Gleixner
2014-10-07 7:57 ` Armin Steinhoff
2014-10-09 8:35 ` Operation not permitted / pthread_setschedparam / EOD Armin Steinhoff
2014-10-09 9:41 ` Pavel Vasilyev
2014-10-09 12:22 ` Crowd Funding ? Armin Steinhoff
2014-10-09 21:59 ` Richard Weinberger
2014-10-10 12:14 ` Armin Steinhoff
2014-10-11 10:04 ` Armin Steinhoff
2014-10-05 10:13 ` Operation not permitted / pthread_setschedparam Armin Steinhoff
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