FreeRTOS Support Archive
The FreeRTOS support forum is used to obtain active support directly from Real
Time Engineers Ltd. In return for using our top quality software and services for
free, we request you play fair and do your bit to help others too! Sign up
to receive notifications of new support topics then help where you can.
This is a read only archive of threads posted to the FreeRTOS support forum.
The archive is updated every week, so will not always contain the very latest posts.
Use these archive pages to search previous posts. Use the Live FreeRTOS Forum
link to reply to a post, or start a new support thread.
[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [November 2015 Threads] Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by damv100 on November 3, 2015 Hi everybody,
I got a question on the use of the heap of freertos.
I have configured the total heap size to 4200 bytes :
define configTOTALHEAPSIZE ((size_t)(4200))
I us all this space since when I call xPortGetFreeHeapSize() I got 10 so
only 10 bytes are unused.
However, I don't understand how this space is used. In fact if I sum the
sizes of the tasks stacks, I get only 2000 bytes :
task1 -> 125 words -> 500 bytes
task2 -> 125 words -> 500 bytes
task3 -> 100 words -> 400 bytes
idleTask -> 50 words -> 200 bytes (configMINIMALSTACKSIZE = 50)
timers -> 100 words -> 400 bytes (configTIMERTASKSTACK_DEPTH = 100)
TOTAL 2000 bytes
Is it normal ? Is there any way to knwow what use the other half of the
freeRTOS heap ?
Thank you for your help
Damien
Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by rtel on November 3, 2015 When you create a task both the task stack and the task control block (TCB) come from the heap. If you creates queues or semaphores then the memory from those comes from the heap also. Direct to task notifications are faster than semaphores and do not use memory from the heap. http://www.freertos.org/a00111.html
Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by damv100 on November 3, 2015 Thank you a lot for this quick and clear answer.
I use :
- 1 queue of 6 elements of 1 byte
- 4 binary semaphores
- 1 mutex
- 3 timers
Do you think it explains the 2kB use of heap ?
If so, is there anyway to evaluate the size of each one to replace the bigger elements ?
Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by rtel on November 3, 2015 Probably not.
You can use FreeRTOS+Trace to see memory allocations.
Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by damv100 on November 3, 2015 I didnt manage to make the openOCD work on my target, so bumping the memory to get the freeRTOS+trace output is a problem.
Is there any other way ?
Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by damv100 on November 4, 2015
Appart of the tasks stacks, what is in FreeRTOS heap ?Posted by rtel on November 4, 2015 Other than using the trace, I think you would have to add code, or put a break point in pvPortMalloc() to see what was calling it.
Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.
|