diff options
| author | Harald Gustafsson <harald.gustafsson@ericsson.com> | 2013-11-07 14:43:40 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-01-13 13:41:09 +0100 |
| commit | 755378a47192a3d1f7c3a8ca6c15c1cf76de0af2 (patch) | |
| tree | b5154fe4b499081b76958894bae2c6fa696c1925 /kernel/sched/deadline.c | |
| parent | 239be4a982154ea0c979fca5846349bb68973aed (diff) | |
sched/deadline: Add period support for SCHED_DEADLINE tasks
Make it possible to specify a period (different or equal than
deadline) for -deadline tasks. Relative deadlines (D_i) are used on
task arrivals to generate new scheduling (absolute) deadlines as "d =
t + D_i", and periods (P_i) to postpone the scheduling deadlines as "d
= d + P_i" when the budget is zero.
This is in general useful to model (and schedule) tasks that have slow
activation rates (long periods), but have to be scheduled soon once
activated (short deadlines).
Signed-off-by: Harald Gustafsson <harald.gustafsson@ericsson.com>
Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-7-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/deadline.c')
| -rw-r--r-- | kernel/sched/deadline.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 21f58d26113..3958bc576d6 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -289,7 +289,7 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se) * arbitrary large. */ while (dl_se->runtime <= 0) { - dl_se->deadline += dl_se->dl_deadline; + dl_se->deadline += dl_se->dl_period; dl_se->runtime += dl_se->dl_runtime; } @@ -329,9 +329,13 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se) * * This function returns true if: * - * runtime / (deadline - t) > dl_runtime / dl_deadline , + * runtime / (deadline - t) > dl_runtime / dl_period , * * IOW we can't recycle current parameters. + * + * Notice that the bandwidth check is done against the period. For + * task with deadline equal to period this is the same of using + * dl_deadline instead of dl_period in the equation above. */ static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t) { @@ -355,7 +359,7 @@ static bool dl_entity_overflow(struct sched_dl_entity *dl_se, u64 t) * of anything below microseconds resolution is actually fiction * (but still we want to give the user that illusion >;). */ - left = (dl_se->dl_deadline >> 10) * (dl_se->runtime >> 10); + left = (dl_se->dl_period >> 10) * (dl_se->runtime >> 10); right = ((dl_se->deadline - t) >> 10) * (dl_se->dl_runtime >> 10); return dl_time_before(right, left); |