From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4C87C126.1050203@domain.hid> Date: Wed, 08 Sep 2010 10:00:22 -0700 From: Bob Feretich MIME-Version: 1.0 References: <4C8605E6.4000400@domain.hid> <4C862A3B.2050300@domain.hid> <4C8713A2.9010705@domain.hid> <4C87418D.1090601@domain.hid> In-Reply-To: <4C87418D.1090601@domain.hid> Content-Type: multipart/alternative; boundary="------------090604010204090403020406" Subject: Re: [Xenomai-help] Oops during rt_event_wait(); formerly "How do I force..." List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: xenomai@xenomai.org This is a multi-part message in MIME format. --------------090604010204090403020406 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit I changed the subject from "How do I force a core dump on a page fault event?", because the thread's topic has drifted. Comments inline... On 9/8/2010 12:55 AM, Gilles Chanteperdrix wrote: > ...Snipped... >> No. This problem started occurring when I integrated the whole system >> together. I'm going to have to work on it a bit to reduce it to a >> suitable code segment . >> The Xenomai content of the loop is: >> while (!end) { >> ... >> rc = rt_event_wait(&event1,..); >> ... >> rc = rt_event_clear(&event1,..); >> ... >> rc = rt_event_wait(&event2,..); >> ... >> rc = rt_event_clear(&event2,..); >> ... >> rc = rt_event_wait(&event3, TM_NONBLOC, ...); >> if (rc==0) end = 1; >> } > Is this is a loop using all the CPU (all the events with TM_NONBLOCK) ? No, just the last wait has TM_NONBLOCK. CPU utilization for the task is about 2%. I examined my use of the rt_event mechanism, trying to identify how my use might be unusual. * The above calls are in a rt-user-task and are bracketed with bind/unbind, outside the loop. The task starts in secondary mode, performs the loop in primary mode, then finishes in secondary mode. * rt_event_create and rt_event_delete occur in a rtdm driver init and exit routines. * However, rt_event_signal is invoked in interrupt handlers. I think that this may be unusual. Normally, interrupt handlers would use the rtdm_event mechanism. Could rt_event_signal be sensitive to being invoked from the context of a real time interrupt? Interrupt handler stack space is usually quite small. Does rt_event_signal make heavy use of the stack? Regards, Bob Feretich --------------090604010204090403020406 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: 8bit I changed the subject from "How do I force a core dump on a page fault event?", because the thread's topic has drifted.
Comments inline...
On 9/8/2010 12:55 AM, Gilles Chanteperdrix wrote: 
...Snipped...

No. This problem started occurring when I integrated the whole system 
together. I'm going to have to work on it a bit to reduce it to a 
suitable code segment .
The Xenomai content of the loop is:
while (!end) {
     ...
     rc = rt_event_wait(&event1,..);
     ...
     rc = rt_event_clear(&event1,..);
     ...
     rc = rt_event_wait(&event2,..);
     ...
     rc = rt_event_clear(&event2,..);
     ...
     rc = rt_event_wait(&event3, TM_NONBLOC, ...);
     if (rc==0) end = 1;
}

Is this is a loop using all the CPU (all the events with TM_NONBLOCK) ?
No, just the last wait has TM_NONBLOCK. CPU utilization for the task is about 2%.

I examined my use of the rt_event mechanism, trying to identify how my use might be unusual.
  • The above calls are in a rt-user-task and are bracketed with bind/unbind, outside the loop. The task starts in secondary mode, performs the loop in primary mode, then finishes in secondary mode.
  • rt_event_create and rt_event_delete occur in a rtdm driver init and exit routines.
  • However, rt_event_signal is invoked in interrupt handlers. I think that this may be unusual. Normally, interrupt handlers would use the rtdm_event mechanism. 
Could rt_event_signal be sensitive to being invoked from the context of a real time interrupt?

Interrupt handler stack space is usually quite small. Does rt_event_signal make heavy use of the stack?

Regards,
Bob Feretich
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