[PATCH v2] sched/deadline: fix runtime accounting in documentation

From: Claudio Scordino
Date: Tue Nov 14 2017 - 06:20:07 EST


Signed-off-by: Claudio Scordino <claudio@xxxxxxxxxxxxxxx>
Signed-off-by: Luca Abeni <luca.abeni@xxxxxxxxxxxxxxx>
Acked-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
CC: Jonathan Corbet <corbet@xxxxxxx>
CC: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: linux-doc@xxxxxxxxxxxxxxx
Cc: Tommaso Cucinotta <tommaso.cucinotta@xxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
Documentation/scheduler/sched-deadline.txt | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Documentation/scheduler/sched-deadline.txt b/Documentation/scheduler/sched-deadline.txt
index e89e36e..8ce78f8 100644
--- a/Documentation/scheduler/sched-deadline.txt
+++ b/Documentation/scheduler/sched-deadline.txt
@@ -204,10 +204,17 @@ CONTENTS
It does so by decrementing the runtime of the executing task Ti at a pace equal
to

- dq = -max{ Ui, (1 - Uinact) } dt
+ dq = -max{ Ui / Umax, (1 - Uinact - Uextra) } dt

- where Uinact is the inactive utilization, computed as (this_bq - running_bw),
- and Ui is the bandwidth of task Ti.
+ where:
+
+ - Ui is the bandwidth of task Ti;
+ - Umax is the maximum reclaimable utilization (subjected to RT throttling
+ limits);
+ - Uinact is the (per runqueue) inactive utilization, computed as
+ (this_bq - running_bw);
+ - Uextra is the (per runqueue) extra reclaimable utilization
+ (subjected to RT throttling limits).


Let's now see a trivial example of two deadline tasks with runtime equal
--
2.7.4