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Jean-Luc Béchennec edited this page Mar 24, 2017 · 3 revisions

Measures of time taken by Trampoline Services

Time is measured with a scope between two GPIO output changes.

  • Target: STM32F4 Discovery board from ST, STM32F407VG running at 168MHz
  • Compiler: GCC 4.9.3
  • Optimization: -O3
  • Scope: RIGOL MSO1104Z 100MHz 4 channels oscilloscope.

StartOS

From StartOS to AUTOSTART task: A GPIO output is switched on just before StartOS, A second GPIO output is switched on at start of the AUTOSTART task

  • EXTENDED: 5.8µs
  • STANDARD: 5.6µs

ActivateTask

Lower or equal priority task

An autostart task activates a lower or equal priority task. No preemption occurs. A GPIO output is switched on just before ActivateTask, A second GPIO output is switched on just after ActivateTask.

  • EXTENDED: 2.77µs
  • STANDARD: 2.72µs

Greater priority task

An autostart task activates a higher priority task. A preemption occurs. A GPIO output is switched on just before ActivateTask, A second GPIO output is switched on at start of the activated task.

  • EXTENDED: 5.02µs
  • STANDARD: 5.01µs

SetEvent

Non waiting task

A higher priority AUTOSTART task sets an event to a lower priority AUTOSTART extended task. the extended task is READY but has not yet run, so it is not waiting for an event. A GPIO output is switched on just before SetEvent, A second GPIO output is switched on just after SetEvent.

  • EXTENDED: 2.02µs
  • STANDARD: 1.74µs

Waiting lower priority task

A higher priority task sets an event to a lower priority extended task. the extended task is WAITING. No preemption occurs. A GPIO output is switched on just before SetEvent, A second GPIO output is switched on just after SetEvent.

  • EXTENDED: 3.25µs
  • STANDARD: 3.09µs

Waiting higher priority task

A lower priority task sets an event to a higher priority extended task. the extended task is WAITING. A preemption occurs. A GPIO output is switched on just before SetEvent, A second GPIO output is switched on juste after the WaitEvent.

  • EXTENDED: 5.27µs
  • STANDARD: 4.98µs