SIS in "real time"

[Heinz Junkes]

Identical behavior with xilinx-zynq-a9 (little - endian?). 

What frustrates me much more
is the missing wait and the return value of pthread_cond_timedwait(&cond, &mutex, &timeout) and
that also the join in main will never be reached.

qemu-system-arm -M xilinx-zynq-a9 -m 256M -no-reboot -serial null -serial mon:stdio -nographic -rtc base=localtime,clock=host -kernel build/arm-rtems6-xilinx_zynq_a9_qemu/posix_api/psx_example_2/psx_example_2.exe
<main>: Wait for child thread...
timeval : seconds : 8068
micro seconds : 567993600

timespec seconds : 8068000
nano seconds : 567993610

<child>: Hello World coming to wait!
Error on pthread_cond_timedwait: Success


With the format instructions you suggested, the output at least is ok:

time tv_sec = 567993600, tv_usec = 4470
timeout tv_sec = 567993610, tv_nsec = 4470000

Danke,
Heinz


> On 13. Apr 2021, at 18:23, Gedare Bloom <gedare at rtems.org> wrote:
> 
> Hi Heinz,
> 
> On Tue, Apr 13, 2021 at 7:02 AM Heinz Junkes <junkes at fhi-berlin.mpg.de> wrote:
>> 
>> Unfortunately I still do not understand it. Under Unix it runs perfectly and also the
>> values are displayed correctly.
>> 
> 
> #include <inttypes.h>
> 
> [...]
>  printf("now tv_sec = %" PRIuLEAST64 ", tv_nsec = %d\n", now.tv_sec,
> now.tv_nsec);
> [...]
>  printf("timeout tv_sec = %" PRIuLEAST64 ", tv_nsec = %d\n",
> timeout.tv_sec, timeout.tv_nsec);
> 
> What you observe is an artifact of 32-/64-bit integer conversions in a
> 32-bit big-endian architecture, I suspect.
> 
>> In the debugger, the contents of the structure timespec are displayed correctly.
>> 
>> Another point that probably makes the program hang:
>> 
>> the function pthread_cond_timedwait(&cond, &mutex, &timeout) returns "1" and does not wait for the timeout.
>> This return value should not exist at all?
>> 
>> Under Unix, as expected, "110" is returned. ETIMOUT.
>> 
>> Heinz
>> 
>> 
>>> On 12. Apr 2021, at 20:38, Gedare Bloom <gedare at rtems.org> wrote:
>>> 
>>> On Fri, Apr 9, 2021 at 11:45 AM Heinz Junkes <junkes at fhi-berlin.mpg.de> wrote:
>>>> 
>>>> Jiri, Joel, thanks for your answers.
>>>> 
>>>> @Joel: I was wondering that rtems-examples in psx_example_3 does not wait 3 seconds.
>>>> 
>>>> I made a curious observation:
>>>> 
>>>> in the original code:
>>>> 
>>>>  clock_gettime( CLOCK_REALTIME, &timeout );
>>>>  timeout.tv_sec += 3;
>>>>  timeout.tv_nsec = 0;
>>>>  printf("The task is coming to enter in a timed wait\n");
>>>>  pthread_cond_timedwait(&cond, &mutex, &timeout);
>>>> 
>>>> 
>>>> I then inserted some printfs and found that the "3" is added to the nsec’s.
>>>> 
>>>> Then I added the rtems-timespec-helpers routines, but get the same behavior:
>>>> 
>>>> 
>>>> void * print_hello(void * arg)
>>>> {
>>>> struct timespec now, timeout;
>>>> rtems_timespec_set(&timeout, 3, 0);
>>>> 
>>>> printf("<child>: Hello World! task with max priority \n");
>>>> clock_gettime( CLOCK_REALTIME, &now );
>>>> printf("now tv_sec = %d, tv_nsec = %d\n", now.tv_sec, now.tv_nsec);
>>>> rtems_timespec_add_to(&timeout, &now);
>>>> printf("timeout tv_sec = %d, tv_nsec = %d\n", timeout.tv_sec, timeout.tv_nsec);
>>> 
>>> Please try with the appropriate type sizes and report back what you find.
>>> 
>>> tv_sec is of type time_t
>>> tv_nsec is of type long
>>> 
>>> %d will only take 32b of those values, so you get some kind of garbage
>>> (that can depend on endianness)
>>> 
>>>> printf("The task is coming to enter in a timed wait\n");
>>>> pthread_cond_timedwait(&cond, &mutex, &timeout);
>>>> printf("The task is coming out from the timed wait \n");
>>>> return NULL;
>>>> }
>>>> 
>>>> program output:
>>>> 
>>>> <main> Enter in the main
>>>> Creating first task
>>>> <child>: Hello World! task with max priority
>>>> now tv_sec = 4766459, tv_nsec = 567993600
>>>> timeout tv_sec = 4766459, tv_nsec = 567993603
>>>> The task is coming to enter in a timed wait
>>>> The task is coming out from the timed wait
>>>> First Task created
>>>> Creating second task
>>>> <child>: Hello World! Task with lowest priority Second task created
>>>> <main> Out of the main
>>>> 
>>>> If I now swap the arguments in the set-function , i.e. instead of
>>>> rtems_timespec_set(&timeout, 3, 0);
>>>> 
>>>> rtems_timespec_set(&timeout, 0, 3);
>>>> 
>>>> it looks as it should
>>>> 
>>>> <child>: Hello World! task with max priority
>>>> now tv_sec = 10766729, tv_nsec = 567993600
>>>> timeout tv_sec = 10766732, tv_nsec = 567993600
>>>> The task is coming to enter in a timed wait
>>>> The task is coming out from the timed wait
>>>> First Task created
>>>> Creating second task
>>>> <child>: Hello World! Task with lowest priority Second task created
>>>> <main> Out of the main
>>>> 
>>>> But still no timed wait  recognizable :-(
>>>> 
>>>> Heinz
>>>> 
>>>> 
>>>> 
>>>> _______________________________________________
>>>> users mailing list
>>>> users at rtems.org
>>>> http://lists.rtems.org/mailman/listinfo/users
>> 

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