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--- realtime:sched_rt_throttling [2016/06/23 08:16]
anna-maria removed
+++ — (current)
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-====== Scheduling - RT throttling ======
-Programming failures in real-time applications can cause the entire system to hang. Such a failure could act like a call of a `while(true){}` loop. When the real-time application has the highest possible priority and is scheduled with SCHED_FIFO policy, no other task can preempt it. This leads to the system blocking all other tasks and scheduling this loop with a CPU load of 100 percent. Real-time throttling is a mechanism to avoid such situations by limiting the execution time of real-time tasks per period. The settings are exported into the proc file system. The default settings are:
-  # cat /proc/sys/kernel/sched_rt_period_us
-  1000000
-  # cat /proc/sys/kernel/sched_rt_runtime_us
-To reach a only 50% CPU usage for real-time tasks and a larger period the values can be changed with the following commands:
-  # echo 2000000 > /proc/sys/kernel/sched_rt_period_us
-  # echo 1000000 > /proc/sys/kernel/sched_rt_runtime_us
-Real-time throttling is disabled in case the real-time task runtime has the same length than the the period. This is done automatically by writing `-1` into `sched_rt_runtime_us`:
-  # echo -1 > /proc/sys/kernel/sched_rt_runtime_us
-This mechanism is already implemented in mainline Linux.

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