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| author | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2017-05-11 09:25:04 +0200 |
|---|---|---|
| committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2017-05-11 09:26:09 +0200 |
| commit | 39773ce8bd21fcdf9d43739b56aba7a5fdedd828 (patch) | |
| tree | 9dd6ffdf67b755d87d5da919cd1038153c965890 /c-user/symmetric_multiprocessing_services.rst | |
| parent | hosts.rst: Correct Ubuntu instructions (diff) | |
| download | rtems-docs-39773ce8bd21fcdf9d43739b56aba7a5fdedd828.tar.bz2 | |
c-user: Replace pre-emption with preemption
Diffstat (limited to 'c-user/symmetric_multiprocessing_services.rst')
| -rw-r--r-- | c-user/symmetric_multiprocessing_services.rst | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/c-user/symmetric_multiprocessing_services.rst b/c-user/symmetric_multiprocessing_services.rst index 2a2d669..16005f3 100644 --- a/c-user/symmetric_multiprocessing_services.rst +++ b/c-user/symmetric_multiprocessing_services.rst @@ -347,15 +347,15 @@ executed in a uni-processor configuration and should be assumed to have data synchronization conflicts with what was formerly the highest priority task which executed without conflict. -Disabling of Thread Pre-Emption -------------------------------- +Disabling of Thread Preemption +------------------------------ -A thread which disables pre-emption prevents that a higher priority thread gets +A thread which disables preemption prevents that a higher priority thread gets hold of its processor involuntarily. In uni-processor configurations, this can be used to ensure mutual exclusion at thread level. In SMP configurations, however, more than one executing thread may exist. Thus, it is impossible to ensure mutual exclusion using this mechanism. In order to prevent that -applications using pre-emption for this purpose, would show inappropriate +applications using preemption for this purpose, would show inappropriate behaviour, this feature is disabled in SMP configurations and its use would case run-time errors. @@ -706,7 +706,7 @@ creation. The home scheduler instance can be changed with :ref:`rtems_task_set_scheduler() <rtems_task_set_scheduler>`. Due to the locking protocols a thread may gain access to scheduler nodes of other scheduler instances. This allows the thread to temporarily migrate to another -scheduler instance in case of pre-emption. +scheduler instance in case of preemption. The scheduler infrastructure is based on an object-oriented design. The scheduler operations for a thread are defined as virtual functions. For the @@ -724,7 +724,7 @@ variants. Up to now, only priority-based schedulers are implemented. In case a thread is allowed to use more than one scheduler node it will ask these nodes for help -* in case of pre-emption, or +* in case of preemption, or * an unblock did not schedule the thread, or * a yield was successful. |