Condition Variables for RTEMS

[Gedare Bloom]

You may like to read
http://wiki.rtems.org/wiki/index.php/SMP#Non-Preempt_Mode_for_Mutual_Exclusion
in addition to the Condition Variables project page. You can search
for "condition variable" in a search engine to get some useful
background material. More below.

On Tue, Feb 25, 2014 at 9:45 AM, zhang json <json.a.zhang at gmail.com> wrote:
> Hi all,
>
> I am a student who is preparing for participating  the GSOC2014, and from
> 'Open Project' i found a interesting project 'Condition Variables'. So i
> want to know the basic information about the status of this project.
>
> There is a bug [1] which is maybe related to it but it seems that
> 'Condition Variables' is not the main problem of this bug. So my confusion
> is blow:
>
> 1. As one of the classic operating system synchronization primitives whether
> RTEMS has a basic 'Condition Variables' support?
RTEMS lacks a condition variable (monitor) implementation within the
classic API located in cpukit/rtems/*, and also within the supercore
"kernel" interface located in cpukit/score/*. There is condition
variables support in posix, as the
cpukit/posix/include/rtems/posix/condimpl.h.

> 2. If answer not from 1, what is the requirement of the implementation?
It should implement a classic API condition variable that can be
similar to the classic API implementation of semaphore
(cpukit/rtems/include/rtems/rtems/sem.h and semimpl.h). The condition
variable should be implemented in the supercore (cpukit/score) and
that implementation should be shared by the posix condvar and the
classic API condition variables.

> 3. Whether its implementation should support SMP?
>
The implementation must support SMP.

Gedare

>
>
> 1. https://www.rtems.org/bugzilla/show_bug.cgi?id=1467
>
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