From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4F0C8D0F.3080207@domain.hid> Date: Tue, 10 Jan 2012 14:10:07 -0500 From: Makarand Pradhan MIME-Version: 1.0 References: <4F0B530A.80905@domain.hid> <4F0C5524.9020501@domain.hid> <4F0C58B7.1080602@domain.hid> <4F0C5C00.3060508@domain.hid> <4F0C5C02.50308@domain.hid> <4F0C5C63.40105@domain.hid> <4F0C5E85.5080004@domain.hid> <4F0C7EAE.8080209@domain.hid> <4F0C85E2.1070109@domain.hid> In-Reply-To: <4F0C85E2.1070109@domain.hid> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Issue with Auto relax and nested mutexes List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai@xenomai.org The patch does work. Thanks. Will it be available in the next release of xenomai? Rgds, Mak root@domain.hid:~# ./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@domain.hid:~# 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@domain.hid:~# ./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@domain.hid:~# ./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 >>>>>>>>> Xenomai-help@domain.hid >>>>>>>>> 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 > Xenomai-help@domain.hid > 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. _____________________________________________________________________