On 2014-06-09 22:42, Joel Sherrill wrote:
This scheduler attempts to account for needed thread migrations caused
as a side-effect of a thread state, affinity, or priority change operation.
This scheduler has its own allocate_processor handler named
_Scheduler_SMP_Allocate_processor_exact() because
_Scheduler_SMP_Allocate_processor() attempts to prevent an executing
thread from moving off its current CPU without considering affinity.
Without this, the scheduler makes all the right decisions and then
they are discarded at the end.
==Side Effects of Adding This Scheduler==
Added Thread_Control * parameter to Scheduler_SMP_Get_highest_ready type
so methods looking for the highest ready thread can filter by the processor
on which the thread blocking resides. This allows affinity to be considered.
Simple Priority SMP and Priority SMP ignore this parameter.
+ Added get_lowest_scheduled argument to _Scheduler_SMP_Enqueue_ordered().
+ Added allocate_processor argument to _Scheduler_SMP_Enqueue_ordered().
+ Added allocate_processor argument to
_Scheduler_SMP_Enqueue_scheduled_ordered().
+ schedulerprioritysmpimpl.h is a new file with prototypes for methods
which were formerly static in schedulerprioritysmp.c but now need to
be public to be shared with this scheduler.
NOTE:
_Scheduler_SMP_Get_lowest_ready() appears to have a path which would
allow it to return a NULL. Previously, _Scheduler_SMP_Enqueue_ordered()
would have asserted on it. If it cannot return a NULL,
_Scheduler_SMP_Get_lowest_ready() should have an assertions.
---
cpukit/score/Makefile.am | 1 +
.../rtems/score/schedulerpriorityaffinitysmp.h | 68 +++-
.../include/rtems/score/schedulerprioritysmpimpl.h | 84 ++++
.../score/include/rtems/score/schedulersmpimpl.h | 102 +++--
cpukit/score/preinstall.am | 4 +
cpukit/score/src/schedulerpriorityaffinitysmp.c | 495 +++++++++++++++++++-
cpukit/score/src/schedulerprioritysmp.c | 32 +-
cpukit/score/src/schedulersimplesmp.c | 12 +-
8 files changed, 727 insertions(+), 71 deletions(-)
create mode 100644 cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
[...]
diff --git a/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
b/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
new file mode 100644
index 0000000..2d8d1a5
--- /dev/null
+++ b/cpukit/score/include/rtems/score/schedulerprioritysmpimpl.h
@@ -0,0 +1,84 @@
+/**
+ * @file
+ *
+ * @ingroup ScoreSchedulerPrioritySMP
+ *
+ * @brief Deterministic Priority SMP Scheduler API
+ */
+
+/*
+ * Copyright (c) 2013-2014 embedded brains GmbH. All rights reserved.
+ *
+ * embedded brains GmbH
+ * Dornierstr. 4
+ * 82178 Puchheim
+ * Germany
+ * <[email protected]>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#ifndef _RTEMS_SCORE_SCHEDULERPRIORITYSMPIMPL_H
+#define _RTEMS_SCORE_SCHEDULERPRIORITYSMPIMPL_H
+
+#include <rtems/score/scheduler.h>
+#include <rtems/score/schedulerpriority.h>
+#include <rtems/score/schedulersmp.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * @ingroup ScoreSchedulerPrioritySMP
+ * @{
+ */
+
+Scheduler_priority_SMP_Context *_Scheduler_priority_SMP_Get_self(
+ Scheduler_Context *context
+);
+
+Scheduler_priority_SMP_Node *_Scheduler_priority_SMP_Node_get(
+ Thread_Control *thread
+);
+
+void _Scheduler_priority_SMP_Insert_ready_fifo(
+ Scheduler_Context *context,
+ Thread_Control *thread
+);
+
+void _Scheduler_priority_SMP_Insert_ready_lifo(
+ Scheduler_Context *context,
+ Thread_Control *thread
+);
+
+void _Scheduler_priority_SMP_Move_from_scheduled_to_ready(
+ Scheduler_Context *context,
+ Thread_Control *scheduled_to_ready
+);
+
+void _Scheduler_priority_SMP_Move_from_ready_to_scheduled(
+ Scheduler_Context *context,
+ Thread_Control *ready_to_scheduled
+);
+
+void _Scheduler_priority_SMP_Extract_from_ready(
+ Scheduler_Context *context,
+ Thread_Control *thread
+);
+
+void _Scheduler_priority_SMP_Do_update(
+ Scheduler_Context *context,
+ Scheduler_Node *base_node,
+ Priority_Control new_priority
+);
Functions used only via the function pointers should be provided as static
inline so that the compiler can optimize more easily.
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* _RTEMS_SCORE_SCHEDULERPRIORITYSMPIMPL_H */
diff --git a/cpukit/score/include/rtems/score/schedulersmpimpl.h
b/cpukit/score/include/rtems/score/schedulersmpimpl.h
index bb7c41e..5356de9 100644
--- a/cpukit/score/include/rtems/score/schedulersmpimpl.h
+++ b/cpukit/score/include/rtems/score/schedulersmpimpl.h
@@ -275,7 +275,14 @@ extern "C" {
*/
typedef Thread_Control *( *Scheduler_SMP_Get_highest_ready )(
- Scheduler_Context *context
+ Scheduler_Context *context,
+ Thread_Control *blocking
+);
+
+typedef Thread_Control *( *Scheduler_SMP_Get_lowest_scheduled )(
+ Scheduler_Context *context,
+ Thread_Control *thread,
+ Chain_Node_order order
);
typedef void ( *Scheduler_SMP_Extract )(
@@ -304,6 +311,12 @@ typedef void ( *Scheduler_SMP_Enqueue )(
Thread_Control *thread_to_enqueue
);
+typedef void ( *Scheduler_SMP_Allocate_processor )(
+ Scheduler_SMP_Context *self,
+ Thread_Control *scheduled,
+ Thread_Control *victim
+);
+
static inline Scheduler_SMP_Context *_Scheduler_SMP_Get_self(
Scheduler_Context *context
)
@@ -382,7 +395,7 @@ static inline void _Scheduler_SMP_Update_heir(
}
}
-static inline void _Scheduler_SMP_Allocate_processor(
+static void _Scheduler_SMP_Allocate_processor(
Should be "static inline".
Scheduler_SMP_Context *self,
Thread_Control *scheduled,
Thread_Control *victim
@@ -420,10 +433,13 @@ static inline void _Scheduler_SMP_Allocate_processor(
}
}
-static inline Thread_Control *_Scheduler_SMP_Get_lowest_scheduled(
- Scheduler_SMP_Context *self
+static Thread_Control *_Scheduler_SMP_Get_lowest_scheduled(
+ Scheduler_Context *context,
+ Thread_Control *filter,
+ Chain_Node_order order
)
{
+ Scheduler_SMP_Context *self = _Scheduler_SMP_Get_self( context );
Thread_Control *lowest_ready = NULL;
Chain_Control *scheduled = &self->Scheduled;
@@ -431,6 +447,12 @@ static inline Thread_Control
*_Scheduler_SMP_Get_lowest_scheduled(
lowest_ready = (Thread_Control *) _Chain_Last( scheduled );
}
+ /*
+ * _Scheduler_SMP_Enqueue_ordered() assumes that get_lowest_scheduled
+ * helpers may return NULL. But this method never should.
+ */
+ _Assert( lowest_ready != NULL );
+
return lowest_ready;
}
@@ -443,28 +465,45 @@ static inline Thread_Control
*_Scheduler_SMP_Get_lowest_scheduled(
* @param[in] thread The thread to enqueue.
* @param[in] order The order function.
* @param[in] insert_ready Function to insert a node into the set of ready
- * nodes.
+ * nodes.
* @param[in] insert_scheduled Function to insert a node into the set of
- * scheduled nodes.
+ * scheduled nodes.
* @param[in] move_from_scheduled_to_ready Function to move a node from the
set
- * of scheduled nodes to the set of ready nodes.
+ * of scheduled nodes to the set of ready nodes.
+ * @param[in] get_lowest_scheduled Function to select the thread from the
+ * scheduled nodes to replace. It may not be possible to find one.
+ * @param[in] allocate_processor Function to allocate a processor to a thread
+ * based on the rules of the scheduler.
*/
static inline void _Scheduler_SMP_Enqueue_ordered(
- Scheduler_Context *context,
- Thread_Control *thread,
- Chain_Node_order order,
- Scheduler_SMP_Insert insert_ready,
- Scheduler_SMP_Insert insert_scheduled,
- Scheduler_SMP_Move move_from_scheduled_to_ready
+ Scheduler_Context *context,
+ Thread_Control *thread,
+ Chain_Node_order order,
Its not aligned thoroughly.
+ Scheduler_SMP_Insert insert_ready,
+ Scheduler_SMP_Insert insert_scheduled,
+ Scheduler_SMP_Move move_from_scheduled_to_ready,
+ Scheduler_SMP_Get_lowest_scheduled get_lowest_scheduled,
+ Scheduler_SMP_Allocate_processor allocate_processor
)
{
Scheduler_SMP_Context *self = _Scheduler_SMP_Get_self( context );
Thread_Control *lowest_scheduled =
- _Scheduler_SMP_Get_lowest_scheduled( self );
+ ( *get_lowest_scheduled )( context, thread, order );
- _Assert( lowest_scheduled != NULL );
+ /*
+ * get_lowest_scheduled can return a NULL if no scheduled threads
+ * should be removed from their processor based on the selection
+ * criteria. For example, this can occur when the affinity of the
+ * thread being enqueued schedules it against higher priority threads.
+ * A low priority thread with affinity can only consider the threads
+ * which are on the cores if has affinity for.
+ *
+ * The get_lowest_scheduled helper should assert on not returning NULL
+ * if that is not possible for that scheduler.
+ */
- if ( ( *order )( &thread->Object.Node, &lowest_scheduled->Object.Node ) ) {
+ if ( lowest_scheduled &&
+ ( *order )( &thread->Object.Node, &lowest_scheduled->Object.Node ) ) {
I will send a patch that moves this NULL pointer check into the order function
once this is committed.
[...]
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : [email protected]
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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