On 01/10/2012 08:10 PM, Makarand Pradhan wrote:
The patch does work. Thanks.Will it be available in the next release of xenomai?
This needs more testing, but this bug is a must fix for 2.6.1 for sure. Your test code does help a lot in this respect. Thanks for the heads up.
Rgds, Mak root@ruggedcom:~# ./relax 0 1 Spawning: tasks bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Grabbing mux in HP Mux held by Task2 Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete ^C root@ruggedcom:~# On 10/01/12 01:39 PM, Makarand Pradhan wrote:Hi Phillipe, A bit surprised to see a change in sched-rt.h. I had another problem earlier where the XNOTHER was not getting set after a priority change. I had to look at the code that you have modified. Although I had temporarily worked around it by setting the XNOTHER in rt_task_set_priority. I think this would fix that problem as well. Will test the patch and get back with the results. Thanks and Rgds, Mak. On 10/01/12 01:08 PM, Philippe Gerum wrote:On 01/10/2012 04:51 PM, Makarand Pradhan wrote:Based on my testing, it is noted that the rescnt is not released when task1 gets a priority boost and starts running with priority 1. That's when the rescnt is not decremented. It would imply that we may be checking the current priority while testing if we want to invoke rt_mutex_release in kernel. Will try to check it out.Does this help in your case? diff --git a/include/nucleus/sched-rt.h b/include/nucleus/sched-rt.h index cc1cefa..6ac8fd7 100644 --- a/include/nucleus/sched-rt.h +++ b/include/nucleus/sched-rt.h @@ -87,7 +87,7 @@ static inline void __xnsched_rt_setparam(struct xnthread *thread, { thread->cprio = p->rt.prio; if (xnthread_test_state(thread, XNSHADOW)) { - if (thread->cprio) + if (thread->bprio || !xnthread_test_state(thread, XNBOOST)) xnthread_clear_state(thread, XNOTHER); else xnthread_set_state(thread, XNOTHER);Rgds, Mak. On 10/01/12 10:42 AM, Philippe Gerum wrote:On 01/10/2012 04:40 PM, Philippe Gerum wrote:On 01/10/2012 04:40 PM, Makarand Pradhan wrote:Another point: "These are fast mutexes, the thread does not have to jump to kernel space unless the released mutex was actually contented." When the first task is started with prio 0, I always see that rt_mutex_release is invoked in the kernel. even when there is no contention.I should have added: "unless there is no contention ... or the caller is a non-rt thread". This is because we have to jump to kernel space to track rescnt.Ok, next try: "unless the mutex was contented ... or the caller is a non-rt thread".I have an instrumented kernel. The kernel trace is given below. In this trace only task1 is running at prio 0. It should be easy to follow: Jan 10 10:36:59 ruggedcom kernel: lo: rescnt: 0, switched: 0 Jan 10 10:36:59 ruggedcom kernel: hi: rescnt: 0, switched: 0 Jan 10 10:36:59 ruggedcom kernel: lo: rescnt: 1, switched: 1 Jan 10 10:36:59 ruggedcom kernel: hi: rescnt: 2, switched: 0 Jan 10 10:36:59 ruggedcom kernel: hi: rescnt: 3, switched: 0 Jan 10 10:37:01 ruggedcom kernel: hi: rescnt: 3, switched: 0 Jan 10 10:37:01 ruggedcom kernel: __rt_mutex_release Jan 10 10:37:01 ruggedcom kernel: RML Jan 10 10:37:01 ruggedcom kernel: rt_mutex_release: lockcnt: 1 Jan 10 10:37:01 ruggedcom kernel: xnsynch_release_thread: BP: 0 Jan 10 10:37:01 ruggedcom kernel: hi: rescnt: 2, switched: 0 Jan 10 10:37:01 ruggedcom kernel: __rt_mutex_release Jan 10 10:37:01 ruggedcom kernel: RML Jan 10 10:37:01 ruggedcom kernel: rt_mutex_release: lockcnt: 1 Jan 10 10:37:01 ruggedcom kernel: xnsynch_release_thread: BP: 0 Jan 10 10:37:01 ruggedcom kernel: hi: rescnt: 1, switched: 0 Jan 10 10:37:01 ruggedcom kernel: __rt_mutex_release Jan 10 10:37:01 ruggedcom kernel: RML Jan 10 10:37:01 ruggedcom kernel: rt_mutex_release: lockcnt: 1 Jan 10 10:37:01 ruggedcom kernel: xnsynch_release_thread: BP: 0 Jan 10 10:37:01 ruggedcom kernel: hi: rescnt: 0, switched: 0 Jan 10 10:37:01 ruggedcom kernel: lo: rescnt: 1, switched: 1 Jan 10 10:37:01 ruggedcom kernel: hi: rescnt: 2, switched: 0 Jan 10 10:37:01 ruggedcom kernel: hi: rescnt: 3, switched: 0 Jan 10 10:37:03 ruggedcom kernel: hi: rescnt: 3, switched: 0 Jan 10 10:37:03 ruggedcom kernel: __rt_mutex_release Jan 10 10:37:03 ruggedcom kernel: RML Jan 10 10:37:03 ruggedcom kernel: rt_mutex_release: lockcnt: 1 Jan 10 10:37:03 ruggedcom kernel: xnsynch_release_thread: BP: 0 Jan 10 10:37:03 ruggedcom kernel: hi: rescnt: 2, switched: 0 Jan 10 10:37:03 ruggedcom kernel: __rt_mutex_release Jan 10 10:37:03 ruggedcom kernel: RML Jan 10 10:37:03 ruggedcom kernel: rt_mutex_release: lockcnt: 1 Jan 10 10:37:03 ruggedcom kernel: xnsynch_release_thread: BP: 0 Jan 10 10:37:03 ruggedcom kernel: hi: rescnt: 1, switched: 0 Jan 10 10:37:03 ruggedcom kernel: __rt_mutex_release Jan 10 10:37:03 ruggedcom kernel: RML Jan 10 10:37:03 ruggedcom kernel: rt_mutex_release: lockcnt: 1 Jan 10 10:37:03 ruggedcom kernel: xnsynch_release_thread: BP: 0 Jan 10 10:37:03 ruggedcom kernel: hi: rescnt: 0, switched: 0 Jan 10 10:37:03 ruggedcom kernel: lo: rescnt: 1, switched: 1 Jan 10 10:37:03 ruggedcom kernel: hi: rescnt: 2, switched: 0 Jan 10 10:37:03 ruggedcom kernel: hi: rescnt: 3, switched: 0 Jan 10 10:37:04 ruggedcom kernel: hi: rescnt: 3, switched: 0 root@ruggedcom:~# ./a.out 0 1 Spawning: tasks bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete ^C Rgds, Mak. On 10/01/12 10:26 AM, Makarand Pradhan wrote:Hi Phillippe, You are right. Task 1 requires to be started with prio 0. I start seeing the problem after task2 grabs the mutex and releases them. The first task never jumps back to seconodary. Here is my output. The mode never goes back to 0 after "Grabbing mux in HP" and the rescnt stays stuck at 1 in the kernel. root@ruggedcom:~# ./relax 0 1 Spawning: tasks bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Grabbing mux in HP Mux held by Task2 Release complete bP: 0, cp: 0, mode: 1 Acquire complete Release complete bP: 0, cp: 0, mode: 1 Acquire complete Rgds, Mak. On 10/01/12 10:11 AM, Philippe Gerum wrote:On 01/09/2012 09:50 PM, Makarand Pradhan wrote:Hi, I am running kernel 3.0.0, xenomai: 2.6, powerpc 8360. I am noticing an issue while using the auto relax feature related to mutexes. I am using nested mutexes. The code is attached to this email. The problem is that I am not relaxing after a RT thread grabs and releases a mutex. On further investigation, it was noted that the rescnt is not going down to 0.From your code, task1 would auto-relax only if started with priority 0, which is what I get here: -bash-3.2# ./relax 0 1 Spawning: tasks bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete bP: 0, cp: 0, mode: 0 Acquire complete Release complete ... Conversely, I get the right behavior if setting a non-zero priority to task1: -bash-3.2# ./relax 1 0 Spawning: tasks bP: 1, cp: 1, mode: 1 Acquire complete Release complete bP: 1, cp: 1, mode: 1 Acquire complete Release complete bP: 1, cp: 1, mode: 1 Acquire complete ... In any case, the priority of task2 should have no impact on the result. I'm running current 2.6 HEAD commit (168da46de), kernel 3.1.5/powerpc32 (52xx), pipeline 2.13-06. Which priority arguments are you passing to your test program?Another observation is that I do not hit rt_mutex_release in the kernel in the problem scenario, I believe when the thread undergoes a priority inversion.This may be a problem as the rescnt would not get decremented. Not sure how the mutex is releasing wiithout hitting rt_mutex_relase or am I missing anything?These are fast mutexes, the thread does not have to jump to kernel space unless the released mutex was actually contented.If I have both the tasks running at priority 0, I stay in the secondary domain, rt_mutex_release is invoked as expected, the rescnt goes down to 0 when all the mutexes are released. Has anyone faced this problem?I'm unsure there is any yet. Auto-relax applies to non -rt Xenomai threads only (i.e. prio == 0).Rgds, Makarand _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help-- ___________________________________________________________________________ NOTICE OF CONFIDENTIALITY: This e-mail and any attachments may contain confidential and privileged information. If you are not the intended recipient, please notify the sender immediately by return e-mail and delete this e-mail and any copies. Any dissemination or use of this information by a person other than the intended recipient is unauthorized and may be illegal. _____________________________________________________________________ _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
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