Compiler Trap-If-Late Instruction for Dynamic Timing Verification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing compiler technologies rely on static timing analysis, which may be too strict or inaccurate in cases with data-dependent code, leading to false rejections or warnings, as they use worst-case metrics that do not account for statistically unlikely input patterns or impossible execution paths.
Innovation Solution
A compiler that inserts a 'trap-if-late' instruction into the compiled code, allowing for runtime checks to ensure timing constraints are met, and a processor with logic to decode and execute this instruction, generating an exception if the execution time is late relative to a target value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If static timing analysis using worst-case metrics is used, then timing constraints can be verified, but false rejections occur for statistically unlikely or impossible execution paths
Solution Approach 1:
The patent transitions from static timing analysis to dynamic timing verification by inserting runtime trap instructions into the compiled code. These instructions actively monitor execution time during actual program runs, allowing the system to adapt timing verification to real execution paths rather than relying on predetermined worst-case scenarios. This dynamic approach resolves the contradiction by making timing checks accurate to actual behavior while maintaining reliability through continuous monitoring.
Solution Approach 2:
The trap instructions provide feedback mechanisms that actively report when timing constraints are violated during execution. By incorporating runtime feedback loops where the processor monitors its own timing compliance and can trigger exceptions or corrections, the system achieves both reliable verification and precise measurement. The feedback from actual execution paths eliminates false rejections while maintaining constraint enforcement.
2Reliability
If worst-case metric is used for data-dependent code, then timing safety can be ensured, but code rejection occurs for statistically tolerable frequency violations
Solution Approach 1:
The system dynamically adjusts timing verification based on actual runtime behavior rather than static worst-case assumptions. By using trap instructions that monitor real execution paths, the system can distinguish between genuinely unsafe code and code that merely exceeds timing constraints under statistically unlikely conditions. This increases compilation success rate while preserving timing safety for actual execution scenarios.
Solution Approach 2:
The patent changes the parameter of timing verification from fixed worst-case metrics to dynamic runtime measurements. By modifying how timing is measured and evaluated - using actual execution time data captured by trap instructions rather than predetermined worst-case values - the system achieves both reliability and higher productivity by accepting code that meets timing constraints under normal operating conditions.
3Ease of manufacture
If static analysis is used for data-dependent code, then compilation is simple, but timing analysis becomes too strict and inaccurate
Solution Approach 1:
The patent segments the compilation process into two distinct phases: a simple static compilation phase that generates code with embedded trap instructions, and a dynamic runtime phase where actual timing verification occurs. This segmentation maintains compilation simplicity by keeping the compiler's role limited to inserting monitoring instructions, while transferring the complex timing analysis to runtime execution where actual data values are known, thereby achieving both ease of manufacture and measurement precision.
Solution Approach 2:
The trap instructions serve as intermediaries between the compiler and the timing verification process. Rather than requiring the compiler to perform complex dynamic analysis, the trap instructions mediate by capturing runtime timing data and enabling verification without burdening the compilation process. This intermediary approach preserves compilation simplicity while achieving accurate timing measurement during execution.
Data Source
Figure 1a~1b
Figure 2
AI summary
One aspect of the present invention provides processor comprising: an execution unit arranged to execute a sequence of instructions each comprising a respective opcode; and a counter coupled to the execution unit and arranged to generate a periodically updated counter value during execution. The execution unit comprises logic configured to identify an opcode representing a trap-if-late instruction in said sequence, and in response to execute the trap-if-late instruction by comparing a target value to the counter value and generating an exception on condition that the counter value represents a time that is late relative to said target value. Another aspect provides a compiler for inserting trap-if-late instructions based on timing constraints in higher-level code.