MANAGING HIGH-CONFLICT CACHE LINES IN TRANSACTIONAL MEMORY COMPUTING ENVIRONMENTS

摘要

Cache lines in a computing environment with transactional memory are configurable with a coherency mode. Cache lines in full-line coherency mode are operated or managed with full-line granularity. Cache lines in sub-line coherency mode are operated or managed as sub-cache line portions of a full cache line. When a transaction accessing a cache line in full-line coherency mode results in a transactional abort, the cache line may be placed in sub-line coherency mode if the cache line is a high-conflict cache line. The cache line may be associated with a counter in a conflict address detection table that is incremented whenever a transaction conflict is detected for the cache line. The cache line may be a high-conflict cache line when the counter satisfies a high-conflict criterion, such as reaching a threshold value. The cache line may be returned to full-line coherency mode when a reset criterion is satisfied.

主权项

1. A method for reducing transaction conflicts in a computing environment with transactional memory, the computing environment including a cache configured to hold a plurality of cache lines, each cache line configurable with a coherency mode, the method comprising:
executing a first transaction in the computing environment, the first transaction accessing a first cache line in a full-line coherency mode, wherein cache control logic associated with the cache is configured to operate or manage the first cache line in the full-line coherency mode with a full-line granularity; detecting a conflicting access of the first cache line while executing the first transaction, the conflicting access resulting in a transactional abort; based on the detecting, placing the first cache line in a sub-line coherency mode, wherein the cache control logic is configured to operate or manage a plurality of sub-cache line portions of the first cache line in the sub-line coherency mode; and executing a subsequent transaction in the computing environment, the subsequent transaction accessing and managing only a relevant sub-cache line portion of the first cache line in the sub-line coherency mode.