[Boost-bugs] [Boost C++ Libraries] #8494: Added comments how to solve the priority inversion problem

Subject: [Boost-bugs] [Boost C++ Libraries] #8494: Added comments how to solve the priority inversion problem
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-04-25 15:17:19

#8494: Added comments how to solve the priority inversion problem
---------------------------------------------------------+------------------
 Reporter:  Peter Brockamp <p.brockamp@…>                |       Owner:  johnmaddock
     Type:  Patches                                      |      Status:  new        
Milestone:  To Be Determined                             |   Component:  config     
  Version:  Boost 1.54.0                                 |    Severity:  Cosmetic   
 Keywords:  vxworks priority inversion                   |  
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 Hello!

 This is //not// a bug but just an added documentation:

 With Real Time OSes there does exist a general problematic scenario,
 called "priority inversion" (see
 http://en.wikipedia.org/wiki/Priority_inversion). When using POSIX
 semaphores a certain default is being used by every OS if not some
 deviating attributes are used to instanciate a semaphore object. boost in
 general uses mainly the OS-defaults, which basically is fine. However for
 RTP's (Real Time Processes) !VxWorks does use a POSIX-semaphore object
 which does //not// adhere to the priority inversion scenario. This could
 possibly lead to a deadlock!

 I added some documentation how to circumvent this problem. This is being
 done by changing the defaults the OS uses for semaphores, and thus does
 not include any changes in boost's code (and could thus not be comitted
 into boost) but on the contrary includes changes in the OS code itself and
 afterwards rebuilding the OS (which is supported for !VxWorks).

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/8494>
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