Prediction Logic Reducing Trace Data Volume in Processors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing operating frequency of processors and the use of multi-processor systems generate excessive trace data, making existing tracing methods costly and inefficient, especially for instruction and data trace streams, as they require significant bandwidth and storage resources.
Innovation Solution
Implementing prediction logic within data processing apparatuses to anticipate the behavior of data processing components, such as predicting branch destinations, and using trace logic to monitor and output prediction indicators, reducing the need to transmit detailed trace data by indicating prediction correctness or errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If full state trace data is output for every instruction processed, then complete diagnostic information is obtained, but trace data volume becomes prohibitively large and expensive
Solution Approach 1:
The patent extracts only the essential diagnostic information from the full processor state by using prediction logic to determine what data is actually needed for debugging. Instead of transmitting the complete processor state, only prediction indicators and necessary trace data are output, reducing data volume while maintaining diagnostic capability.
Solution Approach 2:
The prediction logic operates in advance to predict branch destinations and processor behavior before the actual execution occurs. This preliminary prediction allows the trace logic to prepare and output only the necessary diagnostic information, avoiding the need to transmit complete state data for every instruction.
2Quantity of substance
If compression is used to reduce trace data for indirect branch instructions, then average bits per instruction are reduced, but compression effectiveness is limited and data volume remains high
Solution Approach 1:
The patent changes the fundamental parameter of data representation from complete state data to prediction indicators. By using Boolean or enumeration values to indicate prediction correctness rather than transmitting full branch target addresses, the data is transformed into a form that is both smaller and more compressible.
Solution Approach 2:
Instead of compressing the complete trace data after generation, the invention inverts the approach by generating only the compressed prediction indicator data from the start. The trace logic outputs prediction correctness indicators rather than full state data, fundamentally changing what needs to be compressed.
3Speed
If processor operating frequency is increased to improve performance, then processing speed increases, but trace data generation rate increases proportionally making tracing more difficult
Solution Approach 1:
The prediction logic extracts only the essential diagnostic information needed for tracing at high speeds. By determining what data is actually necessary for debugging and outputting only prediction indicators rather than complete state data, the system maintains effective tracing even at elevated processor frequencies.
Solution Approach 2:
The prediction logic performs preliminary determination of branch destinations and processor behavior before execution occurs. This advance prediction allows the trace system to prepare minimal diagnostic data output in advance, reducing the real-time data generation burden during high-speed processor operation.
Data Source
AI summary
A data processing apparatus is disclosed including trace logic for monitoring behavior of a portion of said data processing apparatus and prediction logic for providing at least one prediction as to at least one step of the behavior of the portion of the data processing apparatus. The trace logic monitors behavior of the portion of the data processing apparatus, determines from the monitored behavior whether the at least one prediction is correct, and outputs a prediction indicator indicating whether the at least one prediction is correct.