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US 10,540,283 B2Granted
Coherence de-coupling buffer
AssigneeFacebook, Inc.
InventorGuillermo J. Rozas
Life of this patent
Estimating the term…
Abstract
A coherence decoupling buffer. In accordance with a first embodiment, a coherence decoupling buffer is for storing tag information of cache lines evicted from a plurality of cache memories. A coherence decoupling buffer may be free of value information of the plurality of cache memories. A coherence decoupling buffer may also be combined with a coherence memory.
Claims20
A method comprising:
- receiving a communication from a remote source to a local caching agent that is configured to interact with a local cache memory;
- initiating a responsive action to the communication by using a coherence memory and a coherence decoupling buffer, which are each configured to filter different types of communications from the remote source to the local caching agent, the coherence decoupling buffer being configured to filter queries to cache lines that are known not to be included within the local cache memory, and the coherence memory being configured to filter read-only queries for cache lines that are already contained within the local cache memory, preventing such read-only queries from being sent to the local cache memory;
- and upon determining that communication from the remote source to the local caching agent was unfiltered by the coherence decoupling buffer and the coherence memory, propagating the communication to the local caching agent to perform the responsive acting in the local cache memory.
A method comprising:
- receiving a cache line status message from a remote source to a local caching agent, the local caching agent being configured to interact with a local cache memory;
- initiating a responsive action to the cache line status message by using cache line tag content associated with the local caching agent and stored in a coherence memory and a coherence decoupling buffer, wherein the coherence memory and the coherence decoupling buffer are each configured to filter different types of cache line status messages from the remote source to the local caching agent, the coherence decoupling buffer being configured to filter queries to cache lines that are known not to be included within the local cache memory, and the coherence memory being configured to filter read-only queries for cache lines that are already contained within the local cache memory, preventing such read-only queries from being sent to the local cache memory;
- and upon determining that at least one of the cache line status messages from the remote source to the local caching agent was not filtered by the coherence decoupling buffer and the coherence memory, propagating the cache line status message to the local caching agent to perform the responsive action in the local cache memory.
A method comprising:
- receiving a remote snoop from a remote source to a local caching agent that is configured to interact with a local cache memory;
- initiating a responsive action to the remote snoop by using first cache line tag content associated with the local caching agent and stored in a coherence memory;
- if the first cache line tag content stored in the coherence memory is insufficient for the responsive action, using second cache line tag content associated with the local caching agent and stored in a coherence decoupling buffer for the responsive action, wherein the coherence memory and the coherence decoupling buffer are each configured to filter different types of remote snoops from the remote source to the local caching agent, the coherence decoupling buffer being configured to filter queries to cache lines that are known not to be included within the local cache memory, and the coherence memory being configured to filter read-only queries for cache lines that are already contained within the local cache memory, preventing such read-only queries from being sent to the local cache memory;
- and
- upon determining that the remote snoop from the remote source to the local caching agent was unfiltered by the coherence decoupling buffer and the coherence memory, propagating the remote snoop to the local caching agent to perform the responsive action in the local cache memory.
2 more elements
Dependencies are inferred from the claim text.