CONFIGURE_MINIMUM_TASK_STACK_SIZE

[Joel Sherrill]

On 12/07/2011 03:48 PM, Chris Johns wrote:
> On 8/12/11 5:39 AM, Gedare Bloom wrote:
>> CONFIGURE_MINIMUM_TASK_STACK_SIZE can be defined by an application to
>> increase the size of all of its task stacks (and implicitly the init
>> task and interrupt stacks). It seems wrong/wasteful to propagate the
>> user-defined CONFIGURE_MINIMUM_TASK_STACK_SIZE to both the idle and
>> interrupt stacks, perhaps these should be CPU_STACK_MINIMUM_SIZE
>> unless defined by the user explicitly?
>>
> What does a minimum stack size mean ?
>
> I have always assumed this setting provides enough stack so the tests
> could run across a number of platforms. I do not use it in any
> applications I develop.
It is more of a "enough to run hello" type of definition.  If you
have less than this, then you are likely in trouble. Many tests
do 2-3 times minimum for their task stacks.
> Yes it would seem to be wasteful for idle. The init task is tricky
> because static constructors run on it.
Nope. Static constructors run in the first init task.
> If you use the BSP init code in
> bsp/shared where your entry point is main the network stack maybe
> started. There is also the implicit stack in the BSP context that starts
> RTEMS. These all require the user's involvement to make sure they are
> big enough.
The stack the BSP starts on is very special and has to be
established outside RTEMS.  We can't do much about that
at this level.

With that said, many BSPs specify where this stack is in
the linker script and have a variable like StackSize that
you can -D on the ld command to increase.

Your network example would impact the init task.
>
> Chris
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Joel Sherrill, Ph.D.             Director of Research&  Development
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