From a1f7d7d430466fe66ead3155a9015ddde237fd44 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Tue, 24 Jul 2018 09:00:18 +0200 Subject: score: RTEMS_PREDICT_TRUE(), RTEMS_PREDICT_FALSE() Add RTEMS_PREDICT_TRUE() and RTEMS_PREDICT_FALSE() for static branch prediction hints. Close #3475. --- cpukit/include/rtems/score/basedefs.h | 28 ++++++++++++++++++++++++++++ cpukit/posix/src/sempost.c | 4 ++-- cpukit/posix/src/semtimedwait.c | 2 +- cpukit/posix/src/semtrywait.c | 2 +- cpukit/score/src/condition.c | 4 +++- cpukit/score/src/futex.c | 2 +- cpukit/score/src/mutex.c | 16 ++++++++-------- cpukit/score/src/semaphore.c | 10 +++++----- testsuites/sptests/spmisc01/init.c | 25 +++++++++++++++++++++++++ 9 files changed, 74 insertions(+), 19 deletions(-) diff --git a/cpukit/include/rtems/score/basedefs.h b/cpukit/include/rtems/score/basedefs.h index 8169f6db8c..679f4bd1b4 100644 --- a/cpukit/include/rtems/score/basedefs.h +++ b/cpukit/include/rtems/score/basedefs.h @@ -281,6 +281,34 @@ #define RTEMS_DEFINE_GLOBAL_SYMBOL( _name, _value ) #endif +/** + * @brief Returns the value of the specified integral expression and tells the + * compiler that the predicted value is true (1). + * + * @param[in] _exp The expression. + * + * @return The value of the expression. + */ +#if defined(__GNUC__) + #define RTEMS_PREDICT_TRUE( _exp ) __builtin_expect( ( _exp ), 1 ) +#else + #define RTEMS_PREDICT_TRUE( _exp ) ( _exp ) +#endif + +/** + * @brief Returns the value of the specified integral expression and tells the + * compiler that the predicted value is false (0). + * + * @param[in] _exp The expression. + * + * @return The value of the expression. + */ +#if defined(__GNUC__) + #define RTEMS_PREDICT_FALSE( _exp ) __builtin_expect( ( _exp ), 0 ) +#else + #define RTEMS_PREDICT_FALSE( _exp ) ( _exp ) +#endif + #if __cplusplus >= 201103L #define RTEMS_STATIC_ASSERT(cond, msg) \ static_assert(cond, # msg) diff --git a/cpukit/posix/src/sempost.c b/cpukit/posix/src/sempost.c index de0ae71fc7..d750c1178c 100644 --- a/cpukit/posix/src/sempost.c +++ b/cpukit/posix/src/sempost.c @@ -40,13 +40,13 @@ int sem_post( sem_t *_sem ) heads = sem->Queue.Queue.heads; count = sem->count; - if ( __predict_true( heads == NULL && count < SEM_VALUE_MAX ) ) { + if ( RTEMS_PREDICT_TRUE( heads == NULL && count < SEM_VALUE_MAX ) ) { sem->count = count + 1; _Sem_Queue_release( sem, level, &queue_context ); return 0; } - if ( __predict_true( heads != NULL ) ) { + if ( RTEMS_PREDICT_TRUE( heads != NULL ) ) { const Thread_queue_Operations *operations; Thread_Control *first; diff --git a/cpukit/posix/src/semtimedwait.c b/cpukit/posix/src/semtimedwait.c index 9e7bb466dd..16d0c24c9f 100644 --- a/cpukit/posix/src/semtimedwait.c +++ b/cpukit/posix/src/semtimedwait.c @@ -46,7 +46,7 @@ int sem_timedwait( executing = _Sem_Queue_acquire_critical( sem, &queue_context ); count = sem->count; - if ( __predict_true( count > 0 ) ) { + if ( RTEMS_PREDICT_TRUE( count > 0 ) ) { sem->count = count - 1; _Sem_Queue_release( sem, level, &queue_context ); return 0; diff --git a/cpukit/posix/src/semtrywait.c b/cpukit/posix/src/semtrywait.c index 673343d4b4..759744ec8e 100644 --- a/cpukit/posix/src/semtrywait.c +++ b/cpukit/posix/src/semtrywait.c @@ -35,7 +35,7 @@ int sem_trywait( sem_t *_sem ) _Sem_Queue_acquire_critical( sem, &queue_context ); count = sem->count; - if ( __predict_true( count > 0 ) ) { + if ( RTEMS_PREDICT_TRUE( count > 0 ) ) { sem->count = count - 1; _Sem_Queue_release( sem, level, &queue_context ); return 0; diff --git a/cpukit/score/src/condition.c b/cpukit/score/src/condition.c index 9913d86d34..892245baf5 100644 --- a/cpukit/score/src/condition.c +++ b/cpukit/score/src/condition.c @@ -279,7 +279,9 @@ static void _Condition_Wake( struct _Condition_Control *_condition, int count ) * In common uses cases of condition variables there are normally no threads * on the queue, so check this condition early. */ - if ( __predict_true( _Thread_queue_Is_empty( &condition->Queue.Queue ) ) ) { + if ( + RTEMS_PREDICT_TRUE( _Thread_queue_Is_empty( &condition->Queue.Queue ) ) + ) { _Condition_Queue_release( condition, &context.Base ); return; } diff --git a/cpukit/score/src/futex.c b/cpukit/score/src/futex.c index 6487882819..f32a13c449 100644 --- a/cpukit/score/src/futex.c +++ b/cpukit/score/src/futex.c @@ -151,7 +151,7 @@ int _Futex_Wake( struct _Futex_Control *_futex, int count ) * called in the fast path. Normally there are no threads on the queue, so * check this condition early. */ - if ( __predict_true( _Thread_queue_Is_empty( &futex->Queue.Queue ) ) ) { + if ( RTEMS_PREDICT_TRUE( _Thread_queue_Is_empty( &futex->Queue.Queue ) ) ) { _Futex_Queue_release( futex, level, &context.Base ); return 0; } diff --git a/cpukit/score/src/mutex.c b/cpukit/score/src/mutex.c index e2f5bb52fc..8cc47f28bb 100644 --- a/cpukit/score/src/mutex.c +++ b/cpukit/score/src/mutex.c @@ -128,7 +128,7 @@ static void _Mutex_Release_critical( mutex->Queue.Queue.owner = NULL; _Thread_Resource_count_decrement( executing ); - if ( __predict_true( heads == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( heads == NULL ) ) { _Mutex_Queue_release( mutex, level, queue_context ); } else { _Thread_queue_Context_set_ISR_level( queue_context, level ); @@ -157,7 +157,7 @@ void _Mutex_Acquire( struct _Mutex_Control *_mutex ) owner = mutex->Queue.Queue.owner; - if ( __predict_true( owner == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( owner == NULL ) ) { mutex->Queue.Queue.owner = executing; _Thread_Resource_count_increment( executing ); _Mutex_Queue_release( mutex, level, &queue_context ); @@ -185,7 +185,7 @@ int _Mutex_Acquire_timed( owner = mutex->Queue.Queue.owner; - if ( __predict_true( owner == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( owner == NULL ) ) { mutex->Queue.Queue.owner = executing; _Thread_Resource_count_increment( executing ); _Mutex_Queue_release( mutex, level, &queue_context ); @@ -218,7 +218,7 @@ int _Mutex_Try_acquire( struct _Mutex_Control *_mutex ) owner = mutex->Queue.Queue.owner; - if ( __predict_true( owner == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( owner == NULL ) ) { mutex->Queue.Queue.owner = executing; _Thread_Resource_count_increment( executing ); eno = 0; @@ -270,7 +270,7 @@ void _Mutex_recursive_Acquire( struct _Mutex_recursive_Control *_mutex ) owner = mutex->Mutex.Queue.Queue.owner; - if ( __predict_true( owner == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( owner == NULL ) ) { mutex->Mutex.Queue.Queue.owner = executing; _Thread_Resource_count_increment( executing ); _Mutex_Queue_release( &mutex->Mutex, level, &queue_context ); @@ -301,7 +301,7 @@ int _Mutex_recursive_Acquire_timed( owner = mutex->Mutex.Queue.Queue.owner; - if ( __predict_true( owner == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( owner == NULL ) ) { mutex->Mutex.Queue.Queue.owner = executing; _Thread_Resource_count_increment( executing ); _Mutex_Queue_release( &mutex->Mutex, level, &queue_context ); @@ -339,7 +339,7 @@ int _Mutex_recursive_Try_acquire( struct _Mutex_recursive_Control *_mutex ) owner = mutex->Mutex.Queue.Queue.owner; - if ( __predict_true( owner == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( owner == NULL ) ) { mutex->Mutex.Queue.Queue.owner = executing; _Thread_Resource_count_increment( executing ); eno = 0; @@ -372,7 +372,7 @@ void _Mutex_recursive_Release( struct _Mutex_recursive_Control *_mutex ) nest_level = mutex->nest_level; - if ( __predict_true( nest_level == 0 ) ) { + if ( RTEMS_PREDICT_TRUE( nest_level == 0 ) ) { _Mutex_Release_critical( &mutex->Mutex, executing, level, &queue_context ); } else { mutex->nest_level = nest_level - 1; diff --git a/cpukit/score/src/semaphore.c b/cpukit/score/src/semaphore.c index f76ee332a4..f9b8b48fe1 100644 --- a/cpukit/score/src/semaphore.c +++ b/cpukit/score/src/semaphore.c @@ -53,7 +53,7 @@ void _Semaphore_Wait( struct _Semaphore_Control *_sem ) executing = _Sem_Queue_acquire_critical( sem, &queue_context ); count = sem->count; - if ( __predict_true( count > 0 ) ) { + if ( RTEMS_PREDICT_TRUE( count > 0 ) ) { sem->count = count - 1; _Sem_Queue_release( sem, level, &queue_context ); } else { @@ -86,7 +86,7 @@ int _Semaphore_Wait_timed_ticks( struct _Semaphore_Control *_sem, uint32_t ticks executing = _Sem_Queue_acquire_critical( sem, &queue_context ); count = sem->count; - if ( __predict_true( count > 0 ) ) { + if ( RTEMS_PREDICT_TRUE( count > 0 ) ) { sem->count = count - 1; _Sem_Queue_release( sem, level, &queue_context ); return 0; @@ -121,7 +121,7 @@ int _Semaphore_Try_wait( struct _Semaphore_Control *_sem ) _Sem_Queue_acquire_critical( sem, &queue_context ); count = sem->count; - if ( __predict_true( count > 0 ) ) { + if ( RTEMS_PREDICT_TRUE( count > 0 ) ) { sem->count = count - 1; eno = 0; } else { @@ -145,7 +145,7 @@ void _Semaphore_Post( struct _Semaphore_Control *_sem ) _Sem_Queue_acquire_critical( sem, &queue_context ); heads = sem->Queue.Queue.heads; - if ( __predict_true( heads == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( heads == NULL ) ) { ++sem->count; _Sem_Queue_release( sem, level, &queue_context ); } else { @@ -178,7 +178,7 @@ void _Semaphore_Post_binary( struct _Semaphore_Control *_sem ) _Sem_Queue_acquire_critical( sem, &queue_context ); heads = sem->Queue.Queue.heads; - if ( __predict_true( heads == NULL ) ) { + if ( RTEMS_PREDICT_TRUE( heads == NULL ) ) { sem->count = 1; _Sem_Queue_release( sem, level, &queue_context ); } else { diff --git a/testsuites/sptests/spmisc01/init.c b/testsuites/sptests/spmisc01/init.c index 4fab3f0e84..c406cd07aa 100644 --- a/testsuites/sptests/spmisc01/init.c +++ b/testsuites/sptests/spmisc01/init.c @@ -229,6 +229,31 @@ static void Init(rtems_task_argument arg) rtems_test_assert(RTEMS_XCONCAT(CON, CAT)() == 91); rtems_test_assert(strcmp(RTEMS_STRING(str), "str") == 0); rtems_test_assert(strcmp(RTEMS_XSTRING(STR), "ing") == 0); + + if (RTEMS_PREDICT_TRUE(true)) { + rtems_test_assert(true); + } else { + rtems_test_assert(false); + } + + if (RTEMS_PREDICT_FALSE(true)) { + rtems_test_assert(true); + } else { + rtems_test_assert(false); + } + + if (RTEMS_PREDICT_TRUE(false)) { + rtems_test_assert(false); + } else { + rtems_test_assert(true); + } + + if (RTEMS_PREDICT_FALSE(false)) { + rtems_test_assert(false); + } else { + rtems_test_assert(true); + } + TEST_END(); rtems_test_exit(0); } -- cgit v1.2.3