[PATCH 3/3] c-user/rate_monotonic_manager.rst: Use Latex math for utilization formulas
Joel Sherrill
joel at rtems.org
Fri Mar 10 21:29:45 UTC 2017
---
c-user/rate_monotonic_manager.rst | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/c-user/rate_monotonic_manager.rst b/c-user/rate_monotonic_manager.rst
index 05eb59f..1309a88 100644
--- a/c-user/rate_monotonic_manager.rst
+++ b/c-user/rate_monotonic_manager.rst
@@ -267,21 +267,19 @@ Processor Utilization Rule
The Processor Utilization Rule requires that processor utilization be
calculated based upon the period and execution time of each task. The fraction
-of processor time spent executing task index is ``Time(index) /
-Period(index)``. The processor utilization can be calculated as follows:
+of processor time spent executing task index is ``Time(i) / Period(i)``.
+The processor utilization can be calculated as follows:
-.. code-block:: c
+.. math::
- Utilization = 0
- for index = 1 to maximum_tasks
- Utilization = Utilization + (Time(index)/Period(index))
+ Utilization = \sum_{i=1}^{maximumTasks} Time_i/Period_i
To ensure schedulability even under transient overload, the processor
utilization must adhere to the following rule:
-.. code-block:: c
+.. math::
- Utilization = maximum_tasks * (2**(1/maximum_tasks) - 1)
+ maximumUtilization = maximumTasks * (2^{\frac{1}{maximumTasks}} - 1)
As the number of tasks increases, the above formula approaches ln(2) for a
worst-case utilization factor of approximately 0.693. Many tasks sets can be
--
1.8.3.1
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