System for dynamically generating, correlating and reading multiprocessing trace data in a shared memory

A method of providing diagnostic trace data for a data processing system comprising

• performing a plurality of interleaved data processing task functions,
• relative to any of said data processing task functions, selectively storing self-diagnostic trace data in a memory shared between all of said data processing task functions,
• relative to said trace data stored by any of said task functions, reading respective said trace data from said shared memory without interrupting or suspending performance of task functions unassociated with said respective trace data, and
• relative to said respective trace data read from said shared memory, and without interrupting or suspending performance of any unassociated said task function, correlating said trace data into a single output, said single output showing a sequential interaction of said plurality of interleaved data processing functions, and
• relative to any of said data processing task functions, attempting to access said shared memory and if access fails setting a flag to disable tracing calls from said any tasks, and
• relative to any of said data processing task functions, sending a trace message to said shared memory and indicating to the trace function that a message is waiting to be displayed.

A data processing system comprising

• a plurality of interleaved data processing task function modules,
• each said data processing task function module being configured to selectively generate self-diagnostic trace data,
• a memory shared between said data processing task function modules,
• said task function modules including means for storing said selectively generated trace data in portions of said shared memory selectively allocated to respective task function modules, and
• a trace function module separate from said task function modules,
• said trace function module including means for reading said trace data from said memory, without interrupting performance of any task function unassociated with the data that is being read, and means for combining all of the trace data read from said memory into a single correlated output function, said output function showing a sequential relation between trace data generated sequentially by said plurality of interleaved data processing task function modules, and
• said task function modules including means for attempting to access said shared memory and if access fails setting a flag to disable tracing calls from said any task, and
• said tasks function modules including means for sending a trace message to said shared memory and indicating to the trace function that a message is waiting to be displayed.