Optimization issue in RISC-V BSP

[Joel Sherrill]

On Fri, Jul 28, 2017 at 2:50 PM, Denis Obrezkov <denisobrezkov at gmail.com>
wrote:

>
>>> I can see that during task initialization I have a call:
>>>  _Thread_Initialize_information (information=information at entry=0x80000ad4
>>> <_RTEMS_tasks_Information>, the_api=the_api at entry=OBJECTS_CLASSIC_API,
>>> the_class=the_class at entry=1, maximum=124,
>>>     is_string=is_string at entry=false, maximum_name_length=maximum_na
>>> me_length at entry=4)
>>>
>>> And maximum is 124, but I have a configuration parameter:
>>> #define CONFIGURE_MAXIMUM_TASKS             4
>>>
>>
>> I can't imagine any standard RTEMS test configuring that many tasks.
>> Is there a data corruption issue?
>>
>> 124 = 0x7c which doesn't ring any bells for me on odd memory issues.
>>
>> What is the contents of "Configuration_RTEMS_API"?
>>
> Oh, I change my configuration options a bit, they are:
>   #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
>   #define CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
>   #define CONFIGURE_DISABLE_NEWLIB_REENTRANCY
>   #define CONFIGURE_TERMIOS_DISABLED
>   #define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 0
>   #define CONFIGURE_MINIMUM_TASK_STACK_SIZE 512
>   #define CONFIGURE_MAXIMUM_PRIORITY 3
>   #define CONFIGURE_DISABLE_CLASSIC_API_NOTEPADS
>   #define CONFIGURE_IDLE_TASK_BODY Init
>   #define CONFIGURE_IDLE_TASK_INITIALIZES_APPLICATION
>   #define CONFIGURE_TASKS 4
>
>   #define CONFIGURE_MAXIMUM_TASKS             4
>
>   #define CONFIGURE_UNIFIED_WORK_AREAS
>
> Also it is the test from a lower ticker example.
> Configuration_RTEMS_API with -O0 option:
> {maximum_tasks = 5, maximum_timers = 0, maximum_semaphores = 7,
> maximum_message_queues = 0, maximum_partitions = 0, maximum_regions = 0,
> maximum_ports = 0, maximum_periods = 0,
>   maximum_barriers = 0, number_of_initialization_tasks = 0,
> User_initialization_tasks_table = 0x0}
>
> with -Os option:
> {maximum_tasks = 124, maximum_timers = 0, maximum_semaphores = 7,
> maximum_message_queues = 0, maximum_partitions = 0, maximum_regions = 0,
> maximum_ports = 0, maximum_periods = 0,
>   maximum_barriers = 0, number_of_initialization_tasks = 0,
> User_initialization_tasks_table = 0x0}
>

Hmmm.. If you look at this structure in gdb without attaching to the
target, what
is maximum_tasks?

--joel

>
>
>
>>
>>>
>>> It seems that other tasks are LIBBLOCK tasks.
>>>
>>> Also, this is my Configuration during run:
>>> (gdb) p Configuration.stack_space_size
>>> $1 = 2648
>>> (gdb) p Configuration.work_space_size
>>> $2 = 4216
>>> (gdb) p Configuration.interrupt_stack_size
>>> $3 = 512
>>> (gdb) p Configuration.idle_task_stack_size
>>> $4 = 512
>>>
>>
>> That looks reasonable. Add CONFIGURE_MAXIMUM_PRIORITY and set it to 4.
>> That should
>> reduce the workspace.
>>
>>  long term, we might want to consider lowering it permanently like one of
>> the Coldfires
>> had to. Or change the default scheduler to the Simple one to save memory.
>>
>>
> I haven't dealt with the Scheduler option yet.
>
>
>
> --
> Regards, Denis Obrezkov
>
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