---
doc/user/smp.t | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/doc/user/smp.t b/doc/user/smp.t
index 1b4849a..ba700e0 100644
--- a/doc/user/smp.t
+++ b/doc/user/smp.t
@@ -147,6 +147,44 @@ another processor. So if we enable interrupts during this
transition we have
to provide an alternative task independent stack for this time frame. This
issue needs further investigation.
+@subsection Clustered/Partitioned Scheduling
+
+We have clustered scheduling in case the set of processors of a system is
+partitioned into non-empty pairwise-disjoint subsets. These subsets are called
+clusters. Clusters with a cardinality of one are partitions. Each cluster is
+owned by exactly one scheduler instance.
+
+Clustered/partitioned scheduling helps to control the worst-case latencies in
+the system, see @cite{Brandenburg, Bj??rn B.: Scheduling and Locking in
+Multiprocessor Real-Time Operating Systems. PhD thesis, 2011.
+@uref{http://www.cs.unc.edu/~bbb/diss/brandenburg-diss.pdf}}. The goal is to
+reduce the amount of shared state in the system and thus prevention of lock
+contention. Modern multi-processor systems tend to have several layers of data
+and instruction caches. With clustered/partitioned 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-partition synchronization. In RTEMS there
+are currently three means available
+
+@itemize @bullet
+@item events,
+@item message queues, and
+@item semaphores using the @ref{Semaphore Manager Multiprocessor Resource
+Sharing Protocol} (MrsP).
+@end itemize
+
+The clustered/partitioned scheduling approach enables separation of functions
+with real-time requirements and functions that profit from fairness and high
+throughput provided the scheduler instances are fully decoupled and adequate
+intra-partition synchronization primitives are used. This is work in progress.
+
+For the configuration of clustered/partitioned schedulers see @ref{Configuring
+a System Configuring Clustered/Partitioned Schedulers}.
+
+To set the scheduler of a task see @ref{Symmetric Multiprocessing Services
+SCHEDULER_IDENT - Get ID of a scheduler} and @ref{Symmetric Multiprocessing
+Services TASK_SET_SCHEDULER - Set scheduler of a task}.
+
@subsection Scheduler Helping Protocol
The scheduler provides a helping protocol to support locking protocols like
--
1.8.4.5
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