realtime:documentation:technical_basics:start
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realtime:documentation:technical_basics:start [2018/08/06 13:44] ebugden Fix typo |
realtime:documentation:technical_basics:start [2023/10/03 08:27] costa.shul Dynticks |
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| ======Technical basics: Important aspects for real time====== | ======Technical basics: Important aspects for real time====== | ||
| - | In order to understand the functionality of an RTOS, you need to know | + | In order to understand the functionality of a real-time operating system (RTOS), you need to know |
| about both general and Linux specific mechanisms. | about both general and Linux specific mechanisms. | ||
| Line 7: | Line 7: | ||
| <WRAP half column> | <WRAP half column> | ||
| + | ===== Real-time system ===== | ||
| + | |||
| + | A real-time system is a platform that is running an RTOS and at least one real-time task. An RT task is a task that must be completed before a certain deadline. These tasks can be periodic or aperiodic have a priority to make sure that they are scheduled according to their frequency of execution and the strictness of their deadline. There can also be non real-time tasks running on the system as well. | ||
| + | |||
| ===== Linux specific preemption models ===== | ===== Linux specific preemption models ===== | ||
| Line 16: | Line 20: | ||
| <WRAP rightalign>[[realtime:documentation:technical_basics:preemption_models|Read more about preemption models]]</WRAP> | <WRAP rightalign>[[realtime:documentation:technical_basics:preemption_models|Read more about preemption models]]</WRAP> | ||
| + | |||
| + | ===== Priority inversion - Priority inheritance ===== | ||
| + | |||
| + | When a task with high priority is blocked by one with low priority | ||
| + | because of a mutually exclusive resource, a third task with priority | ||
| + | in between the others can run and finish before the task with the | ||
| + | highest priority resumes. This phenomenon is known as priority | ||
| + | inversion. It can be solved by priority inheritance. | ||
| + | |||
| + | <WRAP rightalign>[[realtime:documentation:technical_basics:pi|Read more about priority inversion and inheritance]]</WRAP> | ||
| </WRAP> | </WRAP> | ||
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| <WRAP rightalign>[[realtime:documentation:technical_basics:sched_policy_prio:start|Read more about policy and priority]]</WRAP> | <WRAP rightalign>[[realtime:documentation:technical_basics:sched_policy_prio:start|Read more about policy and priority]]</WRAP> | ||
| - | </WRAP> | ||
| - | <WRAP half column> | ||
| ===== Scheduling - RT throttling ===== | ===== Scheduling - RT throttling ===== | ||
| Line 39: | Line 51: | ||
| <WRAP rightalign>[[realtime:documentation:technical_basics:sched_rt_throttling|Read more about RT throttling]]</WRAP> | <WRAP rightalign>[[realtime:documentation:technical_basics:sched_rt_throttling|Read more about RT throttling]]</WRAP> | ||
| - | </WRAP> | ||
| - | <WRAP half column> | + | ===== Latency ===== |
| - | ===== Priority inversion - Priority inheritance ===== | + | |
| - | When a task with high priority is blocked by one with low priority | + | Low latency is a critical requirement in real-time computing environments because it ensures that tasks or processes can respond quickly and predictably to external events or inputs. |
| - | because of a mutually exclusive resource, a third task with priority | + | |
| - | in between the others can run and finish before the task with the | + | <WRAP rightalign>[[realtime:documentation:technical_basics:latency|Read more about the term latency]]</WRAP> |
| - | highest priority resumes. This phenomenon is known as priority | + | |
| - | inversion. It can be solved by priority inheritance. | + | ===== Dynticks ===== |
| + | |||
| + | Dynticks or Dynamic ticks or **no HZ** mode reduces timer interrupts overhead. | ||
| + | |||
| + | <WRAP rightalign>[[realtime:documentation:howto:tools:ticklesskernel|Read more about the dynamic ticks]]</WRAP> | ||
| - | <WRAP rightalign>[[realtime:documentation:technical_basics:pi|Read more about priority inversion and inheritance]]</WRAP> | ||
| </WRAP> | </WRAP> | ||
realtime/documentation/technical_basics/start.txt · Last modified: 2023/10/03 08:27 by costa.shul
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