score: Implement priority boosting

3 files changed, 15 insertions, 2 deletions

diff --git a/doc/user/glossary.texi b/doc/user/glossary.texi
index f0beeab4d7..bf22cf6133 100644
--- a/doc/user/glossary.texi
+++ b/doc/user/glossary.texi
@@ -505,6 +505,12 @@ A mechanism used to represent the relative
 importance of an element in a set of items.  RTEMS uses priority
 to determine which task should execute.
 
+@item priority boosting
+A simple approach to extend the priority inheritance protocol for clustered
+scheduling is @dfn{priority boosting}.  In case a mutex is owned by a task of
+another cluster, then the priority of the owner task is raised to an
+artificially high priority, the pseudo-interrupt priority.
+
 @item priority inheritance
 An algorithm that calls for
 the lower priority task holding a resource to have its priority
diff --git a/doc/user/sem.t b/doc/user/sem.t
index 6bd22dd3d7..210f1d0d92 100644
--- a/doc/user/sem.t
+++ b/doc/user/sem.t
@@ -115,6 +115,11 @@ for that resource.  Each time a task blocks attempting to obtain
 the resource, the task holding the resource may have its
 priority increased.
 
+On SMP configurations, in case the task holding the resource and the task that
+blocks attempting to obtain the resource are in different scheduler instances,
+the priority of the holder is raised to the pseudo-interrupt priority (priority
+boosting).  The pseudo-interrupt priority is the highest priority.
+
 RTEMS supports priority inheritance for local, binary
 semaphores that use the priority task wait queue blocking
 discipline.   When a task of higher priority than the task
diff --git a/doc/user/smp.t b/doc/user/smp.t
index db4114c564..de07f3c2d9 100644
--- a/doc/user/smp.t
+++ b/doc/user/smp.t
@@ -164,12 +164,14 @@ and instruction caches.  With clustered scheduling it is possible to honour the
 cache topology of a system and thus avoid expensive cache synchronization
 traffic.  It is easy to implement.  The problem is to provide synchronization
 primitives for inter-cluster synchronization (more than one cluster is involved
-in the synchronization process). In RTEMS there are currently three means
+in the synchronization process). In RTEMS there are currently four means
 available
 
 @itemize @bullet
 @item events,
-@item message queues, and
+@item message queues,
+@item semaphores using the @ref{Semaphore Manager Priority Inheritance}
+protocol (priority boosting), and
 @item semaphores using the @ref{Semaphore Manager Multiprocessor Resource
 Sharing Protocol} (MrsP).
 @end itemize