On context switch

Clement FR

Genius 4750 points

Other Parts Discussed in Thread: SYSBIOS

Hello,

Target C6678, latest sysbios used.

Let's assume an application with on a given core :

2 or 3 tasks, a dozen or more semaphores, a few SWIs and HWIs.

How does the time to switch context between tasks evolves in relation with the number of semaphores ?

The question behind this :

does the number of semaphores have a HIGH influence on the context switch time or is there a fixed cost that doesn't evolve much with the number of semaphores ?

Thank you,

Clement

over 11 years ago

0 ScottG over 11 years ago

TI__Mastermind 26780 points

Clement,

Context switch time is *not* affected by the number of semaphores in the application.

Scott

0 Clement FR over 11 years ago in reply to ScottG

Genius 4750 points

Scott,

Then I'm confused.
Maybe context switch time is not the right metric.

Increasing the number of semaphores means more latency in the system no ?

Clement

0 ScottG over 11 years ago in reply to Clement FR

TI__Mastermind 26780 points

Clement,

Increasing the number of semaphores increases memory consumption, but would only affect “latency” if there was a runtime search thru a list of semaphores.

Task context switch may be triggered by a pend or post of an individual semaphore, but is not affected by the number of semaphores in the system.

Scott

0 Clement FR over 11 years ago in reply to ScottG

Genius 4750 points

Thanks for the precisions.

Clément

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On context switch