Changeset 39773ce in rtems-docs


Ignore:
Timestamp:
May 11, 2017, 7:25:04 AM (3 years ago)
Author:
Sebastian Huber <sebastian.huber@…>
Branches:
master
Children:
7f89df8
Parents:
4cc5fcf
git-author:
Sebastian Huber <sebastian.huber@…> (05/11/17 07:25:04)
git-committer:
Sebastian Huber <sebastian.huber@…> (05/11/17 07:26:09)
Message:

c-user: Replace pre-emption with preemption

Location:
c-user
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • c-user/key_concepts.rst

    r4cc5fcf r39773ce  
    272272
    273273Priority inversion is a form of indefinite postponement which is common in
    274 multitasking, pre-emptive executives with shared resources.  Priority inversion
     274multitasking, preemptive executives with shared resources.  Priority inversion
    275275occurs when a high priority tasks requests access to shared resource which is
    276276currently allocated to a low priority task.  The high priority task must block
     
    334334mutex ownership are not blocked with respect to the scheduler and instead
    335335perform a busy wait.  The MrsP uses temporary thread migrations to foreign
    336 scheduler instances in case of a pre-emption of the mutex owner.  This locking
     336scheduler instances in case of a preemption of the mutex owner.  This locking
    337337protocol is available since RTEMS 4.11. It was re-implemented in RTEMS 4.12 to
    338338overcome some shortcomings of the original implementation
  • c-user/symmetric_multiprocessing_services.rst

    r4cc5fcf r39773ce  
    348348which executed without conflict.
    349349
    350 Disabling of Thread Pre-Emption
    351 -------------------------------
    352 
    353 A thread which disables pre-emption prevents that a higher priority thread gets
     350Disabling of Thread Preemption
     351------------------------------
     352
     353A thread which disables preemption prevents that a higher priority thread gets
    354354hold of its processor involuntarily.  In uni-processor configurations, this can
    355355be used to ensure mutual exclusion at thread level.  In SMP configurations,
    356356however, more than one executing thread may exist.  Thus, it is impossible to
    357357ensure mutual exclusion using this mechanism.  In order to prevent that
    358 applications using pre-emption for this purpose, would show inappropriate
     358applications using preemption for this purpose, would show inappropriate
    359359behaviour, this feature is disabled in SMP configurations and its use would
    360360case run-time errors.
     
    707707locking protocols a thread may gain access to scheduler nodes of other
    708708scheduler instances.  This allows the thread to temporarily migrate to another
    709 scheduler instance in case of pre-emption.
     709scheduler instance in case of preemption.
    710710
    711711The scheduler infrastructure is based on an object-oriented design.  The
     
    725725these nodes for help
    726726
    727 * in case of pre-emption, or
     727* in case of preemption, or
    728728* an unblock did not schedule the thread, or
    729729* a yield  was successful.
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