Runtime determination of real time operating systems task timing behavior

A system for prognostication of real time operating system (RTOS) health, the system comprising:

• a memory;
• and
• processor coupled with the memory, the processor configured to operate the RTOS and further to:
• analyze a buffer queue comprising a plurality of buffer queue entries, a buffer queue entry comprising a first task-id of a first task instance executed by the RTOS, a timestamp associated with a start-time and/or an end-time of the task instance;
• determine timing parameters of tasks executed by the RTOS by:
• dequeing the buffer queue entry from the buffer queue;
• comparing the buffer queue entry with a topmost entry of a stack, the stack comprising buffer queue entries;
• in response to determining that the first task-id from the buffer queue entry does not match a second task-id from a topmost entry of a stack comprising buffer queue entries:
• pushing the buffer queue entry as a top-entry in a stack;
• updating a previous time sample value as the timestamp of the buffer queue entry;
• and
• accumulating a temporary execution time value for the second task-id from the stack;
• and
• in response to determining that the first task-id from the buffer queue entry matches the second task-id from the topmost entry of the stack;
• generating an execution time value for the second task-id by adding the accumulated temporary execution time value for the second task-id and a difference between the timestamp from the buffer queue entry and the previous time sample value;
• updating the previous time sample value as the timestamp of the buffer queue entry;
• and
• popping the topmost entry from the stack;
• wherein the temporary execution time value of the second task-id is a duration for a single execution of a task corresponding to the second task-id;
• predicting a failure of the RTOS in response to the temporary execution time value exceeding a predetermined threshold.

A steering system comprising:

• a controller that operates power assist functions of the steering system, the controller using a real time operating system (RTOS), the controller further configured to perform prognostication of health of the RTOS by:
• dequeing a buffer queue entry from a buffer queue, the buffer queue entry comprising a first task-id of a first task instance executed by the RTOS, a timestamp associated with a start-time and/or an end-time of the task instance;
• in response to determining that the first task-id from the buffer queue entry does not match a second task-id from a topmost entry of a stack comprising buffer queue entries:
• pushing the buffer queue entry as a top-entry in a stack;
• updating a previous time sample value as the timestamp of the buffer queue entry;
• accumulating a temporary execution time value for the second task-id from the stack;
• and
• generating an inter-arrival time for the first task-id;
• and
• in response to determining that the first task-id from the buffer queue entry matches the second task-id from the topmost entry of the stack;
• generating an execution time value for the second task-id by adding the accumulated temporary execution time value for the second task-id and a difference between the timestamp from the buffer queue entry and the previous time sample value;
• generating a blocking time for the second task-id by subtracting, from the timestamp from the buffer queue entry, a second timestamp from the topmost entry from the stack and the execution time value for the second task-id;
• updating the previous time sample value as the timestamp of the buffer queue entry;
• and
• popping the topmost entry from the stack;
• wherein the execution time value of the second task-id is a duration for a single execution of a task corresponding to the second task-id;
• predicting a failure of the RTOS in response to the execution time value exceeding a predetermined threshold.