Stack isues

[k-madsenDK]

I got a program with heave use of core0 as web interface and core1 running the main sensor interface.
I got trouble the stack from core0 overwrite core1 stack.
To exchange the 2 stacks i use compiler.cpp.extra_flags=-DPICO_CORE0_STACK_ADDR=0x20041000 -DPICO_CORE1_STACK_ADDR=0x20042000
In platform.txt but I have to do that for every new platform update.
Why just be default have stack1 first and then stack0
For most of the programs running on a pico series is there a big gab between heap in the bottom and the stack in the top.

[earlephilhower]

That's the way the SDK is set up to best price single cycle access to stack RAM units.

The stack moves down and the majority of apps only use the 1st core. So those apps get 8k of stack effectively.

See https://arduino-pico.readthedocs.io/en/latest/multicore.html#stack-sizes for a way to move the 2nd core stack to the top of heap without any special build flags. You're not getting single cycle access if both cores are working in the same 4k stack unit anyway.

If you overflow the stack down into heap, which is what I think your swapping is doing, you will most likely corrupt the heap memory manager. That's not a fun thing to debug.

[k-madsenDK]

I got plenty of space from heap to the stack
my setting is bool core1_separate_stack = true;
compiler.cpp.extra_flags=-DPICO_CORE0_STACK_ADDR=0x2003C000 -DPICO_CORE1_STACK_ADDR=0x20040000 -DPICO_CORE0_STACK_SIZE=16384 -DPICO_CORE1_STACK_SIZE=16384
To be able to adjust stack_size and address from a parameter in the source will be niece , I need to change platform.txt every time you release a new version.