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| -rw-r--r-- | Documentation/scheduler/sched-deadline.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt index 53a2fe1ae8b8..8e37b0ba2c9d 100644 --- a/Documentation/scheduler/sched-deadline.txt +++ b/Documentation/scheduler/sched-deadline.txt @@ -16,6 +16,7 @@ CONTENTS 4.1 System-wide settings 4.2 Task interface 4.3 Default behavior + 4.4 Behavior of sched_yield() 5. Tasks CPU affinity 5.1 SCHED_DEADLINE and cpusets HOWTO 6. Future plans @@ -426,6 +427,23 @@ CONTENTS Finally, notice that in order not to jeopardize the admission control a -deadline task cannot fork. + +4.4 Behavior of sched_yield() +----------------------------- + + When a SCHED_DEADLINE task calls sched_yield(), it gives up its + remaining runtime and is immediately throttled, until the next + period, when its runtime will be replenished (a special flag + dl_yielded is set and used to handle correctly throttling and runtime + replenishment after a call to sched_yield()). + + This behavior of sched_yield() allows the task to wake-up exactly at + the beginning of the next period. Also, this may be useful in the + future with bandwidth reclaiming mechanisms, where sched_yield() will + make the leftoever runtime available for reclamation by other + SCHED_DEADLINE tasks. + + 5. Tasks CPU affinity ===================== |