Analyzing diagnostic data generated by multiple threads within an instruction stream

Abstract

A diagnostic method for outputting diagnostic data relating to processing of instruction streams stemming from a computer program, at least some of said instructions streams comprising multiple threads is disclosed. The method comprises the steps of: (i) receiving diagnostic data; (ii) reordering said received diagnostic data in dependence upon reordering data, said reordering data comprising data relating to said computer program; and (iii) outputting said reordered diagnostic data. In general, the instructions streams are processed by a plurality of processing units arranged to process at least some of said instructions in parallel, said diagnostic data being received from said plurality of processing units.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to the field of data processing and in particular to diagnostic mechanisms for monitoring data processing operations.[0003]2. Description of the Prior Art[0004]Systems are being developed that have multiple processing units operable to process data in parallel. A compiler will compile a program to execute on a particular hardware system such that in a multi-processor system portions of the program will be sent to be executed by different processing units. Thus, much of the program will be executed in parallel and executing times and processing performance will be improved. However, a drawback of this is that the view of the program execution derived from diagnostic mechanisms such as debug are difficult for a programmer to understand and to relate back to the original sequential program.[0005]When an application has been split into multiple threads automatically, there are two conventional ...

AI Technical Summary

Benefits of technology

[0065]As previously mentioned, when compiling a computer program to be processed by a plurality of processing units decisions on how the program is divided and which bits are sent to which processor are made. Thus, if additional information regarding this process can

Problems solved by technology

However, a drawback of this is that the view of the program execution derived from diagnostic mechanisms such as debug are difficult for a programmer to understand and to relate back to the original sequential program.

Clearly this has the disadvantage of not allowing diagnosis of a significant part of the program.

In summary, when multiple processors are executing in parallel and independently producing traces of diagnostic information, it can be hard to understand the resulting traces independently of each other.

While this approach does significantly simplify the event stream, it leaves a significant semantic gap between the program as written by the programmer and the program as executed on the multi-processor system.

This makes debugging the system harder because the programmer must disregard the order of some events (e.g., exactly when does T3 run) while paying careful attention to other events (e.g., that T1 and T2 execute in sequence).

The problem identified above comes from the topological sort making sorting decisions based only on how the hardware runs the output of the transforming compiler.

Furthermore,

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