testing new SMP scheduler

[Gedare Bloom]

On Fri, Jun 14, 2013 at 11:16 AM, Joel Sherrill
<joel.sherrill at oarcorp.com> wrote:
> On 6/14/2013 6:03 AM, Sebastian Huber wrote:
>>
>> On 06/13/2013 11:30 PM, Joel Sherrill wrote:
>>>
>>> Hi
>>>
>>> Out of curiosity, did you hack confdefs.h to force this as the
>>> scheduler in uniprocessor configurations to ensure it does
>>> the correct things in that situation?
>>>
>> I hacked some things to run the tests with the new scheduler.
>
> Unfortunately, I think this is an important thing to test but not
> necessarily
> what you want for systems.
>
>>   I added also the
>> support for the preempt mode (this makes no sense on SMP).
>
> Preemption (and timeslicing) still make sense.  When a task is no preempt,
> it
> should stay on the core until it voluntarily blocks or makes itself
> preemptible.
> This effectively means the scheduler has to avoid kicking it off while no
> preempt.
>
> Does the scheduler take into account "time on CPU" when considering
> tasks of equal priority? It should evict the one which has been executing
> the longest.
>
Why?

>
>>   The following tests
>> fail:
>>
>> sp02 - This is a bug in the test.  I will send a fix.
>> sp66 - I think there is a bug in the test.
>> spfatal03 - Fails due to RTEMS_SMP is defined.
>> tm20 - Didn't look at it since this test tinkers with internal variables.
>> tm27 - Ditto.
>>
>> The test sp66 checks the priority ceiling protocol.  The problem is that
>> the
>> driver task has preemption disabled:
>>
>> [...]
>>     sleep(1);
>>
>>     puts( "Calling semaphore release" );
>>     status = rtems_semaphore_release( Mutex_id );
>>     directive_failed( status, "rtems_semaphore_release" );
>>
>> To make sure the priority ceiling works, we have to check that Task_1
>> actually
>> runs which is impossible since Init has preempt disabled.
>>
>>     puts( "*** END OF TEST 65 ***" );
>>
>>     rtems_test_exit(0);
>> [...]
>>
> Does sp66 run with the uniprocessor schedulers?
>
>
> --
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel.sherrill at OARcorp.com        On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
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>
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