Re: [Xenomai] [QUESTION] thread creation and hook function

[Philippe Gerum <rpm@xenomai.org>]

On 04/15/2013 03:05 PM, Philippe Gerum wrote:
> On 04/15/2013 02:36 PM, Philippe Gerum wrote:
>> On 04/15/2013 12:25 PM, alex alex wrote:
>>> linux kernel : 3.2.21
>>> xenomai version : 2.6.2.1
>>> arch: x86
>>>
>>> Thank, I add your code and now I have :
>>>
>>> case 1 : ( without nanosleep(0) )
>>>
>>>   6138.151187] TRD: 394830ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6138.159924] TRD: 9127501ns - NOM "hook" - CPU 0 - RT:0 - shadow
>>> [ 6138.159953] TRD: 9163835ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6138.160014] TRD: 370242723ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6138.520008] TRD: 370429306ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6139.521009] TRD: 1370433173ns - NOM "hook" - CPU 0 - RT:1 -
>>> user-space
>>> shadow in real-time mode
>>> [ 6139.521014] TRD: 1370446122ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6139.521705] TRD: 1371147808ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6139.521723] TRD: 1371168314ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>>
>>> case 2 : ( with nanosleep(0) before the loop )
>>>
>>> [ 6144.996779] TRD: 382277ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6145.005024] TRD: 8625148ns - NOM "hook" - CPU 0 - RT:0 - shadow
>>> [ 6145.005054] TRD: 8659990ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6145.008013] TRD: 8730535ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6145.008013] TRD: 8734846ns - NOM "hook" - CPU 0 - RT:1 - user-space
>>> shadow in real-time mode
>>> [ 6145.008013] TRD: 367409427ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6145.363763] TRD: 367634768ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6146.363810] TRD: 1367637465ns - NOM "hook" - CPU 0 - RT:1 -
>>> user-space
>>> shadow in real-time mode
>>> [ 6146.363815] TRD: 1367646922ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6146.365055] TRD: 1368896836ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>> [ 6146.365073] TRD: 1368916343ns - NOM "ROOT/0" - CPU 0 - RT:1 - linux
>>>
>>> If I follow these outputs, this means that the loop is made by a linux
>>> task
>>> and if I add a nanosleep just before, the loop is done by the xenomai
>>> task.
>>> Moreover, "hook " switch in primary mode only when it is destroyed
>>> unless we
>>> force a primary switch with nanosleep(0) before the loop.
>>>
>>> Is a xenomai thread shouldn't start in primary mode
>>
>> It certainly does.
>>
>>   or maybe it wait for a
>>> rt service to switch in primary mode?
>>>
>>
>> I can't give you any information. I downloaded your code and can't see
>> any "hook" task. There is a "hook" driver, a "tr_sleep" task, but
>> nothing else. Besides, your Makefile should use xeno-config for getting
>> the proper build flags. Handcrafting this is the fastest path to hell
>> with the POSIX skin.
>>
>> Until I can make sense of the output you mention looking at the actual
>> code, I won't be able to help.
>>
>> /proc/xenomai/sched and /proc/xenomai/stat may help to determine who is
>> running, in which mode.
>>
>
> Note: the _get_time() routine in your driver looks broken.

No I'm wrong, it's probably not, assuming the first shot is ok to return 
a close-to-null figure.

  In addition,
> calling rtdm_printk services from the hook is strongly discouraged
> unless you don't care for timings.
>


-- 
Philippe.