Optimization issue in RISC-V BSP

[Denis Obrezkov]

2017-07-28 22:36 GMT+02:00 Joel Sherrill <joel at rtems.org>:

> Can you check the memory immediately after a download'?
>
> Then after the loop that copies initialized data into place?
>
> I suspect something off there. Could be a linker script issue or the
> copy gone crazy.
>
> --joel
>
> On Fri, Jul 28, 2017 at 3:20 PM, Denis Obrezkov <denisobrezkov at gmail.com>
> wrote:
>
>> 2017-07-28 22:16 GMT+02:00 Joel Sherrill <joel at rtems.org>:
>>
>>>
>>>
>>> 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
>>>>
>>>
>>> maximum_tasks = 4
>> So, is it a linker file issue?
>>
>> This is it:
>> https://github.com/embeddedden/rtems-riscv/blob/hifive1/c/
>> src/lib/libbsp/riscv32/hifive1/startup/linkcmds
>>
>> --
>> Regards, Denis Obrezkov
>>
>
> After download:
{maximum_tasks = 938162044, maximum_timers = 1270834941, maximum_semaphores
= 2534801264, maximum_message_queues = 425684620, maximum_partitions =
1496738036,
  maximum_regions = 3085560870, maximum_ports = 4269782132, maximum_periods
= 2362012542, maximum_barriers = 1138223297, number_of_initialization_tasks
= 4224313421,
  User_initialization_tasks_table = 0x43bd1bd3}

right after data copying:
{maximum_tasks = 124, maximum_timers = 0, maximum_semaphores = 1,
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}

But I found the mistake - I made it in .data initialization code
(
https://github.com/embeddedden/rtems-riscv/blob/hifive1/c/src/lib/libbsp/riscv32/hifive1/start/start.S#L116
- first byte in the loop was uninitialized)


-- 
Regards, Denis Obrezkov
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