Mutex obtain with timeout

[Joel Sherrill]

On 12/18/2014 9:40 AM, Hesham Moustafa wrote:
> On Thu, Dec 18, 2014 at 3:38 PM, Joel Sherrill
> <joel.sherrill at oarcorp.com> wrote:
>>
>> On December 18, 2014 5:18:31 AM PST, Sebastian Huber <sebastian.huber at embedded-brains.de> wrote:
>>> Hello,
>>>
>>> I work currently on concepts to implement mutex objects with SMP aware
>>> locking protocols.  Currently this is MrsP [1] and OMIP [2]. The
>>> implementation should use fine grained locking.  It turned out that the
>>>
>>> support for timeout makes the implementations much more complicated.
>>> With timeouts you can tear a resource dependency tree into two
>>> sub-trees
>>> at arbitrary positions and this makes traversal difficult (you can cut
>>> off the way back).
>>>
>>> Is there a valid use case for a mutex obtain operation with a timeout
>>> in
>>> case the locking protocol aims to provide bounded wait times?  We can
>>> probably also assume that the critical section has a bounded execution
>>> time.
>> I don't know if there is or not. It is close to Christmas but I can try to email Burns and Wellings. I have met them both a few times and they gave usually been quick to answer.
>>
>> Or we could send Hesham to their office hours .. Lol
>>
> Before I read this, I was about to reply that I can contact them faster :)

Please do and if you want to bring Sebastian and/or myself in, feel free to
set up a Google Hangout.

Say hi to them for me. :)
>>> [1] A. Burns , A. J. Wellings, A Schedulability Compatible
>>> Multiprocessor Resource Sharing Protocol -- MrsP, Proceedings of the
>>> 2013 25th Euromicro Conference on Real-Time Systems, p.282-291, July
>>> 09-12, 2013
>>>
>>> [2] Björn B. Brandenburg, A Fully Preemptive Multiprocessor Semaphore
>>> Protocol for Latency-Sensitive Real-Time Applications, Proceedings of
>>> the 2013 25th Euromicro Conference on Real-Time Systems, p.292-302,
>>> July
>>> 09-12, 2013
>>>
>>> --
>>> 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.huber at embedded-brains.de
>>> PGP     : Public key available on request.
>>>
>>> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>>>
>>> _______________________________________________
>>> devel mailing list
>>> devel at rtems.org
>>> http://lists.rtems.org/mailman/listinfo/devel
>> --joel
>> _______________________________________________
>> devel mailing list
>> devel at rtems.org
>> http://lists.rtems.org/mailman/listinfo/devel

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com        On-Line Applications Research
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