Metadata-Dependent ECC Processors for Single-Access Error Correction
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Solution Overview
Problem
Existing error correction systems in system memory face challenges in correcting errors when metadata is not known at the time of error detection, leading to inefficiencies and increased costs due to the need for additional memory access and power consumption.
Innovation Solution
Implementing metadata dependent error correction codes (ECC) that combine metadata and ECC, allowing error correction without additional bits, and using instructions to retrieve metadata values for correction, even when paged out to secondary storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ECC systems store metadata separately from ECC bits, then error correction can be performed, but additional memory access and power consumption are required
Solution Approach 1:
The patent combines metadata and ECC bits into a single unified storage location in system memory. The metadata dependent ECC circuitry retrieves both metadata and ECC bits together in one memory access operation, eliminating the need for separate accesses. This merging resolves the contradiction by maintaining error correction capability while reducing power consumption through fewer memory access operations.
Solution Approach 2:
The unified storage location serves multiple functions: it stores both metadata and ECC bits, and the single memory access operation simultaneously retrieves both components needed for error correction. This multi-functionality approach allows the system to maintain full error correction capability while using a single access operation that would traditionally require two separate accesses, thereby reducing power consumption.
2Reliability
If traditional ECC systems perform separate memory accesses for metadata and ECC bits, then complete error correction information can be retrieved, but access time increases
Solution Approach 1:
The patent merges metadata and ECC bits into the same memory storage location, allowing the metadata dependent ECC circuitry to retrieve both components in a single memory access operation. This eliminates the sequential access time penalty of traditional systems that must first retrieve metadata, then separately retrieve ECC bits, thereby reducing total access time while maintaining complete error correction capability.
3Reliability
If additional ECC bits are used to compensate for metadata storage, then error correction capability is maintained, but memory cost increases
Solution Approach 1:
The patent eliminates the need for additional ECC bits by merging metadata and ECC bits into the same storage location. The metadata dependent ECC circuitry uses the existing ECC bits alongside the retrieved metadata to perform error correction, rather than requiring separate dedicated storage for metadata. This approach maintains full error correction capability without increasing the quantity of memory resources required.
Data Source
AI summary
An apparatus includes a decode unit to decode an instruction. The instruction is to indicate address information corresponding to a location of data having one or more errors in system memory. The apparatus includes an execution unit to perform operations corresponding to the instruction. The operations include determining whether there is only a single metadata value, out of all possible metadata values of a given bit length, which allows a metadata dependent error correction code (ECC) to correct the one or more errors in the data. The metadata dependent ECC corresponds to the data and is stored in the system memory. The operations include either storing the single metadata value in a destination storage location if the determination is that there is only the single metadata value or else indicating the determination is that there is not only the single metadata value. Other apparatus, methods, systems, and instructions are disclosed.