Handy,
In response to question number 2.
Both Priority Ceiling Protocol (pcp) and Priority Inheritance Protocol allow
for a priority boost to a low priority thread that has a lock on a mutex in
which a high priority thread wants access to.
PCP associates a scheduling priority with a mutex. A mutex can assign its
holder with a priority equal to its own if the mutex holder has a lower
priority to begin with. Whenever a low priority thread acquires the mutex,
its priority is elevated to that of the mutex.
PIP lets a mutex elevate the priority of its holder to that of a waiting
thread with a higher priority. The low priority thread is not automatically
elevated in priority when it acquires the mutex. Its priority is only
elevated when a higher priority thread is waiting for the mutex.
For question number 3. My understanding of RTlinux is that priority
inversion is not dealt with and is up to the programmer to avoid priority
inversion situations during code development. I don't know if this is still
the case.
> -----Original Message-----
> From: Handy Madinata [mailto:[EMAIL PROTECTED]]
> Sent: Monday, June 18, 2001 12:08 AM
> To: [EMAIL PROTECTED]
> Subject: [rtl] priority inversion..
>
>
> dear all,
>
> I have questions about priority inversion condition in
> realtime system:
>
> 1. Is it right that priority inversion condition will be a
> problem only if
> its duration is unbound
>
> 2. what is the differences beetwen pcp (priority ceiling
> protocol), its
> emulation, and pip (priority inheritance protocol) because
> they are same
> to me as all of them give the highest process' priority, that
> are blocked
> for a resource, to a process that have lock for that resource
> so that the
> process can't be preempted by any intermediate process.
>
> 3. is it right that for rtlinux, priority inversion problem
> solutions are
> hacking and can cause another problems so leave that
> condition is better
> than solve them
>
> thanks
>
> -======================================-
> Handy Madinata
> students of departement of informatics
> bandung insitut of technology
> indonesia
> -======================================-
>
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