On 13/11/2018 09:37, Malte Münch wrote:
Good morning Sebastian,
thanks for your quick answer. Thanks for your hint on where to look for
the locking. I think i will need some time to understand what each macro
is doing.
My plan with the rtems_task_mode() call was to start there and trace
down to the according kernel call.
Please do not look at the rtems_task_mode() function. It uses a broken
mechanism:
https://devel.rtems.org/ticket/2365
In the operating system implementation disable interrupts to prevent a
thread dispatch or use _Thread_Dispatch_disable().
I will try this approach again with the MrsP implementation: what i need
is a FIFO-queue with spinlock-waiting which is, if i am not wrong, the
mechanism of MrsP with the exception that no priority ceiling per
processor is involved and that no helping mechanism is used.
I would use a debugger and follow the mutex obtain/release sequence in a
test case to figure out what is going on.
Best regards.
Malte
On 12.11.18 11:43, Sebastian Huber wrote:
Hello Malte,
On 12/11/2018 11:28, Malte Münch wrote:
Hi,
i am implementing a new resource sharing protocol for RTEMS as part of
my bachelor thesis. The thesis is about resource sharing protocols in
realtime environments on multicore systems. Right now i have to use a
spinlock for a protocol and found a helpful implementation/function in
cpukit/include/rtems/score/smplockmcs.h. My protocol requires the
calling task to be non-preemptable and the comment for the
acquire-function requires me to disable the interrupts.
the lock API for the operating system implementation is defined in
<rtems/score/isrlock.h>. Please do not use <rtems/score/smplock*.h>
directly.
The comment in cpukit/rtems/src/taskmode.c says that it is not possible
to change either interrupt levels or the preemptability of a task in a
SMP configuration. Do you have a pointer for me on how to overcome this
issue?
You look at the wrong layer. This rtems_task_mode() is a part of the
user API. It should not be used for the operating system implementation
which deals with locking protocols.
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.hu...@embedded-brains.de
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Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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