[PATCH] score: Multiprocessor Resource Sharing Protocol
Sebastian Huber
sebastian.huber at embedded-brains.de
Wed May 21 15:05:22 UTC 2014
On 2014-05-21 16:53, Gedare Bloom wrote:
> On Wed, May 21, 2014 at 8:09 AM, Sebastian Huber
> <sebastian.huber at embedded-brains.de> wrote:
>> Add basic support for the Multiprocessor Resource Sharing Protocol
>> (MrsP).
>>
>> The Multiprocessor Resource Sharing Protocol (MrsP) is defined in A.
>> Burns and A.J. Wellings, A Schedulability Compatible Multiprocessor
>> Resource Sharing Protocol - MrsP, Proceedings of the 25th Euromicro
>> Conference on Real-Time Systems (ECRTS 2013), July 2013. It is a
>> generalization of the Priority Ceiling Protocol to SMP systems. Each
>> MrsP semaphore uses a ceiling priority per scheduler instance. These
>> ceiling priorities can be specified with rtems_semaphore_set_priority().
>> A task obtaining or owning a MrsP semaphore will execute with the
>> ceiling priority for its scheduler instance as specified by the MrsP
>> semaphore object. Tasks waiting to get ownership of a MrsP semaphore
>> will not relinquish the processor voluntarily. In case the owner of a
>> MrsP semaphore gets preempted it can ask all tasks waiting for this
>> semaphore to help out and temporarily borrow the right to execute on one
>> of their assigned processors.
>>
>> The help out feature is not implemented with this patch.
>> ---
>> cpukit/rtems/Makefile.am | 1 +
>> cpukit/rtems/include/rtems/rtems/attr.h | 14 +
>> cpukit/rtems/include/rtems/rtems/attrimpl.h | 31 ++
>> cpukit/rtems/include/rtems/rtems/sem.h | 46 +++
>> cpukit/rtems/include/rtems/rtems/semimpl.h | 9 +
>> cpukit/rtems/src/semcreate.c | 38 ++-
>> cpukit/rtems/src/semdelete.c | 21 +-
>> cpukit/rtems/src/semflush.c | 7 +-
>> cpukit/rtems/src/semobtain.c | 19 +-
>> cpukit/rtems/src/semrelease.c | 14 +-
>> cpukit/rtems/src/semsetpriority.c | 116 +++++++
>> cpukit/sapi/include/confdefs.h | 14 +-
>> cpukit/score/Makefile.am | 2 +
>> cpukit/score/include/rtems/score/mrsp.h | 135 ++++++++
>> cpukit/score/include/rtems/score/mrspimpl.h | 301 +++++++++++++++++
>> cpukit/score/include/rtems/score/schedulerimpl.h | 10 +
>> cpukit/score/preinstall.am | 8 +
>> doc/user/Makefile.am | 2 +-
>> doc/user/conf.t | 32 ++
>> doc/user/sem.t | 198 +++++++++++-
>> testsuites/smptests/Makefile.am | 1 +
>> testsuites/smptests/configure.ac | 1 +
>> testsuites/smptests/smpmrsp01/Makefile.am | 19 ++
>> testsuites/smptests/smpmrsp01/init.c | 287 +++++++++++++++++
>> testsuites/smptests/smpmrsp01/smpmrsp01.doc | 15 +
>> testsuites/smptests/smpmrsp01/smpmrsp01.scn | 2 +
>> testsuites/sptests/Makefile.am | 1 +
>> testsuites/sptests/configure.ac | 1 +
>> testsuites/sptests/spmrsp01/Makefile.am | 19 ++
>> testsuites/sptests/spmrsp01/init.c | 374 ++++++++++++++++++++++
>> testsuites/sptests/spmrsp01/spmrsp01.doc | 13 +
>> testsuites/sptests/spmrsp01/spmrsp01.scn | 8 +
>> 32 files changed, 1743 insertions(+), 16 deletions(-)
>> create mode 100644 cpukit/rtems/src/semsetpriority.c
>> create mode 100644 cpukit/score/include/rtems/score/mrsp.h
>> create mode 100644 cpukit/score/include/rtems/score/mrspimpl.h
>> create mode 100644 testsuites/smptests/smpmrsp01/Makefile.am
>> create mode 100644 testsuites/smptests/smpmrsp01/init.c
>> create mode 100644 testsuites/smptests/smpmrsp01/smpmrsp01.doc
>> create mode 100644 testsuites/smptests/smpmrsp01/smpmrsp01.scn
>> create mode 100644 testsuites/sptests/spmrsp01/Makefile.am
>> create mode 100644 testsuites/sptests/spmrsp01/init.c
>> create mode 100644 testsuites/sptests/spmrsp01/spmrsp01.doc
>> create mode 100644 testsuites/sptests/spmrsp01/spmrsp01.scn
>
> [...]
>
>> diff --git a/cpukit/rtems/src/semflush.c b/cpukit/rtems/src/semflush.c
>> index f73c929..e818d68 100644
>> --- a/cpukit/rtems/src/semflush.c
>> +++ b/cpukit/rtems/src/semflush.c
>> @@ -43,12 +43,17 @@ rtems_status_code rtems_semaphore_flush(
>> {
>> Semaphore_Control *the_semaphore;
>> Objects_Locations location;
>> + rtems_attribute attribute_set;
>>
>> the_semaphore = _Semaphore_Get( id, &location );
>> switch ( location ) {
>>
>> case OBJECTS_LOCAL:
>> - if ( !_Attributes_Is_counting_semaphore(the_semaphore->attribute_set) ) {
>> + attribute_set = the_semaphore->attribute_set;
>> + if ( _Attributes_Is_multiprocessor_resource_sharing( attribute_set ) ) {
>> + _Objects_Put( &the_semaphore->Object );
>> + return RTEMS_NOT_DEFINED;
>> + } else if ( !_Attributes_Is_counting_semaphore( attribute_set ) ) {
>> _CORE_mutex_Flush(
>> &the_semaphore->Core_control.mutex,
>> SEND_OBJECT_WAS_DELETED,
> Need #if defined(RTEMS_SMP)...#endif here.
No. On uni-processor configurations the Priority Ceiling Protocol is used in
case MrsP is selected. Since MrsP will not support the flush operation we have
to issue an error here to be consistent. I will add a comment.
>
>> diff --git a/cpukit/rtems/src/semsetpriority.c b/cpukit/rtems/src/semsetpriority.c
>> new file mode 100644
>> index 0000000..bb3a688
>> --- /dev/null
>> +++ b/cpukit/rtems/src/semsetpriority.c
>> @@ -0,0 +1,116 @@
>> +/*
>> + * Copyright (c) 2014 embedded brains GmbH. All rights reserved.
>> + *
>> + * embedded brains GmbH
>> + * Dornierstr. 4
>> + * 82178 Puchheim
>> + * Germany
>> + * <rtems at embedded-brains.de>
>> + *
>> + * 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.
>> + */
>> +
>> +#if HAVE_CONFIG_H
>> + #include "config.h"
>> +#endif
>> +
>> +#include <rtems/rtems/semimpl.h>
>> +#include <rtems/rtems/attrimpl.h>
>> +#include <rtems/rtems/tasksimpl.h>
>> +#include <rtems/score/schedulerimpl.h>
>> +
>> +static rtems_status_code _Semaphore_Set_priorities(
> Minor nit, should this be named _Semaphore_Set_priority()?
Oh, yes.
>
>> diff --git a/cpukit/sapi/include/confdefs.h b/cpukit/sapi/include/confdefs.h
>> index 1c97d15..f3e5127 100644
>> --- a/cpukit/sapi/include/confdefs.h
>> +++ b/cpukit/sapi/include/confdefs.h
>> @@ -1792,6 +1792,17 @@ const rtems_libio_helper rtems_fs_init_helper =
>> CONFIGURE_SEMAPHORES_FOR_FILE_SYSTEMS + \
>> CONFIGURE_NETWORKING_SEMAPHORES)
>>
>> + #if !defined(RTEMS_SMP) || \
>> + !defined(CONFIGURE_MAXIMUM_MULTIPROCESSOR_RESOURCE_SHARING_SEMAPHORES)
> Can this be CONFIGURE_MAXIMUM_MRSP_SEMAPHORES?
Yes, this is also fine. This
CONFIGURE_MAXIMUM_MULTIPROCESSOR_RESOURCE_SHARING_SEMAPHORES is really a bit long.
>
>
>> diff --git a/cpukit/score/include/rtems/score/mrsp.h b/cpukit/score/include/rtems/score/mrsp.h
>> new file mode 100644
>> index 0000000..4a790d4
>> --- /dev/null
>> +++ b/cpukit/score/include/rtems/score/mrsp.h
>> @@ -0,0 +1,135 @@
>> +/*
>> + * Copyright (c) 2014 embedded brains GmbH. All rights reserved.
>> + *
>> + * embedded brains GmbH
>> + * Dornierstr. 4
>> + * 82178 Puchheim
>> + * Germany
>> + * <rtems at embedded-brains.de>
>> + *
>> + * 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_MRSP_H
>> +#define _RTEMS_SCORE_MRSP_H
>> +
>> +#include <rtems/score/cpuopts.h>
>> +
>> +#if defined(RTEMS_SMP)
>> +
>> +#include <rtems/score/atomic.h>
>> +#include <rtems/score/chain.h>
>> +#include <rtems/score/scheduler.h>
>> +#include <rtems/score/thread.h>
>> +
>> +#ifdef __cplusplus
>> +extern "C" {
>> +#endif /* __cplusplus */
>> +
>> +/**
>> + * @defgroup ScoreMRSP Multiprocessor Resource Sharing Protocol Handler
>> + *
>> + * @ingroup Score
>> + *
>> + * @brief Multiprocessor Resource Sharing Protocol (MrsP).
>> + *
>> + * The Multiprocessor Resource Sharing Protocol (MrsP) is defined in A. Burns
>> + * and A.J. Wellings, A Schedulability Compatible Multiprocessor Resource
>> + * Sharing Protocol - MrsP, Proceedings of the 25th Euromicro Conference on
>> + * Real-Time Systems (ECRTS 2013), July 2013. It is a generalization of the
>> + * Priority Ceiling Protocol to SMP systems. Each MrsP semaphore uses a
>> + * ceiling priority per scheduler instance. A task obtaining or owning a MrsP
>> + * semaphore will execute with the ceiling priority for its scheduler instance
>> + * as specified by the MrsP semaphore object. Tasks waiting to get ownership
>> + * of a MrsP semaphore will not relinquish the processor voluntarily. In case
>> + * the owner of a MrsP semaphore gets preempted it can ask all tasks waiting
>> + * for this semaphore to help out and temporarily borrow the right to execute
>> + * on one of their assigned processors.
>> + *
>> + * @{
>> + */
>> +
>> +/**
>> + * @brief MRSP status code.
>> + *
>> + * The values are chosen to directly map to RTEMS status codes. In case this
>> + * implementation is used for other APIs, then for example the errno values can
>> + * be added with a bit shift.
>> + */
>> +typedef enum {
>> + MRSP_SUCCESSFUL = 0,
>> + MRSP_TIMEOUT = 6,
>> + MRSP_RESOUCE_IN_USE = 12,
>> + MRSP_UNSATISFIED = 13,
>> + MRSP_INVALID_PRIORITY = 19,
>> + MRSP_NOT_OWNER_OF_RESOURCE = 23,
>> + MRSP_NO_MEMORY = 26
>> +} MRSP_Status;
>> +
>> +/**
>> + * @brief MRSP rival.
>> + *
>> + * The rivals are used by threads waiting for resource ownership. They are
>> + * registered in the MRSP control block.
>> + */
>> +typedef struct {
>> + /**
>> + * @brief The node for registration in the MRSP rival chain.
>> + */
>> + Chain_Node Node;
>> +
>> + /**
>> + * @brief Identification of the rival thread.
>> + */
>> + Thread_Control *thread;
>> +
>> + /**
>> + * @brief The rival state.
>> + *
>> + * Initially no state bits are set. The rival will busy wait until a state
>> + * change happens. This an be MRSP_RIVAL_STATE_NEW_OWNER or
> "This an be" -> "This can be"
Ok.
>
>> diff --git a/cpukit/score/include/rtems/score/mrspimpl.h b/cpukit/score/include/rtems/score/mrspimpl.h
>> new file mode 100644
>> index 0000000..7adb88f
>> --- /dev/null
>> +++ b/cpukit/score/include/rtems/score/mrspimpl.h
>> @@ -0,0 +1,301 @@
>> +/*
>> + * Copyright (c) 2014 embedded brains GmbH. All rights reserved.
>> + *
>> + * embedded brains GmbH
>> + * Dornierstr. 4
>> + * 82178 Puchheim
>> + * Germany
>> + * <rtems at embedded-brains.de>
>> + *
>> + * 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_MRSPIMPL_H
>> +#define _RTEMS_SCORE_MRSPIMPL_H
>> +
>> +#include <rtems/score/mrsp.h>
>> +
>> +#if defined(RTEMS_SMP)
>> +
>> +#include <rtems/score/assert.h>
>> +#include <rtems/score/chainimpl.h>
>> +#include <rtems/score/schedulerimpl.h>
>> +#include <rtems/score/watchdogimpl.h>
>> +#include <rtems/score/wkspace.h>
>> +
>> +#ifdef __cplusplus
>> +extern "C" {
>> +#endif /* __cplusplus */
>> +
>> +/**
>> + * @addtogroup ScoreMRSP
>> + *
>> + * @{
>> + */
>> +
>> +#define MRSP_RIVAL_STATE_NEW_OWNER 0x1U
>> +
>> +#define MRSP_RIVAL_STATE_TIMEOUT 0x2U
>> +
> Does it make sense to have MRSP_RIVAL_STATE_WAITING 0x0? Also, the
> functions in this file could use some doxygen.
Ok, I added the MRSP_RIVAL_STATE_WAITING.
Its too early for Doxygen documentation. The implementation is incomplete.
The main purpose of this patch is to add the high-level API.
>
>
>> diff --git a/doc/user/Makefile.am b/doc/user/Makefile.am
>> index ef91a41..e774319 100644
>> --- a/doc/user/Makefile.am
>> +++ b/doc/user/Makefile.am
>> @@ -96,7 +96,7 @@ sem.texi: sem.t
>> -n "Barrier Manager" < $< > $@
>>
>> barrier.texi: barrier.t
>> - $(BMENU2) -p "Semaphore Manager SEMAPHORE_FLUSH - Unblock all tasks waiting on a semaphore" \
>> + $(BMENU2) -p "Semaphore Manager SEMAPHORE_SET_PRIORITY - Set priority by scheduler for a semaphore" \
> This should probably say "Set ceiling priority by scheduler"
>
> -Gedare
>
Since the priority interpretation depends on the locking protocol, we should
not use "ceiling" here. Currently it is always a ceiling priority, but this
may not be the case forever.
--
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 : sebastian.huber at embedded-brains.de
PGP : Public key available on request.
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