Bypassing a store-conditional request around a store queue

摘要

In response to receipt of a store-conditional (STCX) request of a processor core, the STCX request is buffered in an entry of a store queue for eventual service by a read-claim (RC) machine by reference to a cache array, and the STCX request is concurrently transmitted via a bypass path bypassing the store queue. In response to dispatch logic dispatching the STCX request transmitted via the bypass path to the RC machine for service by reference to the cache array, the entry of the STCX request in the store queue is updated to prohibit selection of the STCX request in the store queue for service. In response to the STCX request transmitted via the bypass path not being dispatched by the dispatch logic, the STCX is thereafter transmitted from the store queue to the dispatch logic and dispatched to the RC machine for service by reference to the cache array.

主权项

1. A data processing system comprising:
a processor core; a cache array, a read-claim (RC) machine that services requests of the processor core by reference to the cache array; dispatch logic that dispatches requests of the processor core to the RC machine for service; a store queue coupled between the processor core and dispatch logic, the store queue including a plurality of entries for buffering requests of the processor core; a bypass path coupling the processor core and dispatch logic that bypasses the store queue, wherein a store-conditional (STCX) request of the processor core is buffered in an entry of the store queue for eventual service by the RC machine by reference to the cache array and concurrently transmitted via the bypass path; and a store queue controller that, in response to the dispatch logic dispatching the STCX request transmitted via the bypass path to the RC machine for service by reference to the cache array, updates the entry of the STCX request in the store queue to prohibit selection of the STCX request in the store queue for service, and, in response to the STCX request transmitted via the bypass path not being dispatched by the dispatch logic, causes the STCX to be transmitted from the store queue to the dispatch logic for service.