Apple Inc.
Method and apparatus for ensuring real-time snoop latency

Abstract:

Various systems and methods for ensuring real-time snoop latency are disclosed. A system includes a processor and a cache controller. The cache controller receives, via a channel, cache snoop requests from the processor, the snoop requests including latency-sensitive and non-latency sensitive requests. Requests are not prioritized by type within the channel. The cache controller limits a number of non-latency sensitive snoop requests that can be processed ahead of an incoming latency-sensitive snoop requests. Limiting the number of non-latency sensitive snoop requests that can be processed ahead of an incoming latency-sensitive snoop request includes the cache controller determining that the number of received non-latency sensitive snoop requests has reached a predetermined value and responsively prioritizing latency-sensitive requests over non-latency sensitive requests.