US 2022/0091979 A1 · MAINTAINING DOMAIN COHERENCE STATES INCLUDING DOMAIN STATE NO-OWNED (DSN) IN PROCESSOR-BASED DEVICES

Abstract

Maintaining domain coherence states including Domain State No-Owned (DSN) in processor-based devices is disclosed. In this regard, a processor-based device provides multiple processing elements (PEs) organized into multiple domains, each containing one or more PEs and a local ordering point circuit (LOP). The processor-based device supports domain coherence states for coherence granules cached by the PEs within a given domain. The domain coherence states include a DSN domain coherence state, which indicates that a coherence granule is not cached within a shared modified state within any domain. In some embodiments, upon receiving a request for a read access to a coherence granule, a system ordering point circuit (SOP) determines that the coherence granule is cached in the DSN domain coherence state within a domain of the plurality of domains, and can safely read the coherence granule from the system memory to satisfy the read access if necessary.

Claims30

Dependent claims

A processor-based device, comprising:

a system ordering point circuit (SOP);
a system memory;
a plurality of processing elements (PEs);
and
a plurality of domains, each domain comprising:
one or more PEs of the plurality of PEs;
and
a local ordering point circuit (LOP) communicatively coupled to the one or more PEs and to the SOP;
wherein:
a first LOP of a first domain of the plurality of domains is configured to:
determine that a coherence granule, cached within a local cache of a first PE of the one or more PEs of the first domain as a first cached copy, is not cached with an Owned (O) cache coherence state within any domain of the plurality of domains;
and
update a domain coherence state indicator for the coherence granule to indicate that the coherence granule is cached in a Domain State No-Owned (DSN) domain coherence state within the first domain.

10 more elements

A method, comprising:

determining, by a first local ordering point circuit (LOP) of a processor-based device, the first LOP being within a first domain of a plurality of domains each comprising one or more processing elements (PEs) of a plurality of PEs, that a coherence granule, cached within a local cache of a first PE of the one or more PEs of the first domain as a first cached copy, is not cached with an Owned (O) cache coherence state within any domain of the plurality of domains;
and
updating a domain coherence state indicator for the coherence granule to indicate that the coherence granule is cached in a Domain State No-Owned (DSN) domain coherence state within the first domain.

Dependencies are inferred from the claim text.

Maintaining domain coherence states including domain state no-owned (dsn) in processor-based devices

Life of this patent

Maintaining domain coherence states including domain state no-owned (dsn) in processor-based devices

Life of this patent

Abstract

Claims30