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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
21 years ago

lwIP, uCOSII and task priority ranges

Came over this while trying to figure out why object "sys_stack" occupied half my RAM size in the .elf.

In sys_arch.h:

# define LWIP_MAX_TASKS OS_LOWEST_PRIO /* Number of LwIP tasks */# define LWIP_START_PRIO 0 /* Defined the lowest LwIP task priority */# define LWIP_STACK_SIZE 2048 /* Stack size for LwIP tasks */

/* Note:

Task priorities, LWIP_START_PRIO through (LWIP_START_PRIO+LWIP_MAX_TASKS-1) must be reserved

for LwIP and must not used by other applications outside. */

In sys_arch.c:

OS_STK sys_stack[LWIP_MAX_TASKS][LWIP_STACK_SIZE];

So, this explains my big sys_stack, since I have set OS_LOWEST_PRIO to 63.

My question now, however, is:

If you reserve the range 0 to OS_LOWEST_PRIO for lwIP tasks, is there any prios left for other tasks? Presumption: OS_LOWEST_PRIO = highest number any task can have for priority.

Frode,

Norway

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    21 years ago

    Have put my task priorities closer together and reduced OS_LOWEST_PRIO, hence making sys_stack smaller and saving memory. Did not change anything in sys_arch.*

    All tasks seems to work in harmony.

    Is it so that lwIP doesn't use any other priorities than those I can control from the app as arguments to lwip_stack_init(), lwip_devices_init() and calls to sys_thread_new()?

    In case the Note comment in sys_arch.h makes any sense, wouldn't the constant LWIP_MAX_TASKS be better off configured from the IDE, rather than set to OS_LOWEST_PRIO?

    Frode,

    Norway