Low-latency Register Error Correction via Programmable Atomic Unit
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Solution Overview
Problem
Chiplet systems face latency issues due to register data correction, which disrupts processor operations and adds unnecessary latency even when no errors are detected, as current error correction methods assume error-free data and reschedule instructions upon error detection.
Innovation Solution
A programmable atomic unit (PAU) within the memory controller chiplet performs error checking and correction on register data, allowing for low-latency register error correction by changing the current instruction into a register update instruction and rescheduling it without affecting non-error case latency, using error correction codes and multi-threaded processors to minimize latency penalties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error correction is performed on register data in chiplet systems, then data reliability is improved, but processing latency increases due to instruction rescheduling
Solution Approach 1:
The patent applies preliminary action by performing error detection and correction on register data before the data is used in processing operations. The error correction code (ECC) logic continuously monitors and corrects register data in advance, so that when data is needed for instruction execution, it is already verified and corrected, eliminating the need for latency-inducing instruction rescheduling.
Solution Approach 2:
The patent introduces an intermediary ECC logic component that sits between the register file and the processing units. This intermediary layer performs error detection and correction transparently, allowing the main processing logic to operate without knowing about or being affected by error correction operations, thus avoiding latency penalties from instruction rescheduling.
2Reliability
If traditional error correction methods are used, then data integrity is maintained, but processor operations are disrupted and latency is added
Solution Approach 1:
The patent implements self-service by enabling the register file to perform its own error detection and correction operations autonomously. The ECC logic is integrated directly with the register file, allowing it to self-diagnose and self-correct errors without requiring external intervention or processor intervention, thus maintaining data integrity while avoiding disruptions to processor operations.
Solution Approach 2:
The patent replaces the mechanical instruction rescheduling mechanism with a seamless error correction mechanism. Instead of interrupting processor operations to handle errors (mechanical approach), the error correction is performed transparently in the background through dedicated ECC logic, substituting the disruptive mechanical rescheduling with a smoother, parallel correction process.
3Measurement precision
If error detection is performed on every register read, then error detection capability is improved, but processing speed decreases due to latency penalties
Solution Approach 1:
The patent ensures continuity of useful action by performing error detection continuously and transparently during normal register operations. The ECC logic operates in parallel with data access, continuously monitoring register data without interrupting the flow of processing operations. This maintains high error detection capability while preserving processing speed, as the error detection becomes an integrated, continuous function rather than a discrete, speed-reducing step.
Data Source
AI summary
To achieve low-latency register error correction, a register can be read as part of an instruction when that instruction is the currently executing instruction in a processor. A correctable error in data produced from reading the register can be detected. In response to detecting the correctable error, the currently executing instruction in the processor can be changed into a register update instruction that is executed to overwrite the data in the register with corrected data. Then, the original (e.g., unchanged) instruction can be rescheduled.