Simplified priority inheritance explanation #88
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Add explanation of mutex priority inheritance behavior along with important differences a user should be aware of.
paulbartell
previously approved these changes
Apr 25, 2024
kar-rahul-aws
previously approved these changes
May 2, 2024
joshzarr
reviewed
May 7, 2024
ch08.md
Outdated
| @@ -713,7 +716,7 @@ FreeRTOS mutexes and binary semaphores are very similar—the difference | |||
| being that mutexes include a basic 'priority inheritance' mechanism, | |||
| whereas binary semaphores do not. Priority inheritance is a scheme that | |||
| minimizes the negative effects of priority inversion. It does not 'fix' | |||
| priority inversion, but merely lessens its impact by ensuring that the | |||
| priority inversion, but merely lessens its impact by ensuring that the∏ | |||
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Extra character get introduced?
joshzarr
reviewed
May 7, 2024
ch08.md
Outdated
| @@ -737,6 +740,23 @@ As just seen, priority inheritance functionality effects the priority of | |||
| tasks that are using the mutex. For that reason, mutexes must not be | |||
| used from interrupt service routines. | |||
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| The priority inheritance scheme implemented by FreeRTOS is described as | |||
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Suggestion:
"FreeRTOS implements a basic priority inheritance mechanism which was designed with optimizing both space and execution cycles in mind."
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I'll update this in the next commit
joshzarr
reviewed
May 7, 2024
ch08.md
Outdated
| at a time. | ||
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| Specific behaviors of the priority inheritance mechanism to keep in mind: | ||
| * A task can have an already inherited priority raised further if it |
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Suggestion:
"A task can have an already"
to
"A task can have its already"
joshzarr
reviewed
May 7, 2024
ch08.md
Outdated
| at a time. | ||
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| Specific behaviors of the priority inheritance mechanism to keep in mind: | ||
| * A task can have an already inherited priority raised further if it |
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I would suggest breaking this up into multiple bullet points to make it clear that priority is only disinherited after all mutexes are released. It does not depend on if the second mutex was acquired before or after priority is increased through inheritance.
joshzarr
approved these changes
May 8, 2024
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Description of changes:
Add explanation of mutex priority inheritance
behavior along with important differences a
user should be aware of.
Issue #, if available:
FreeRTOS/FreeRTOS#1168
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