Oracle America, Inc.

Intel Corporation

Sun Microsystems, Inc.

Soft Machines Inc.

Paul G Chan

John Gregory Favor

Joseph Byron Rowlands

Graham Ricketson Murphy

Karthikeyan Avudaiyappan

Ricky C Hetherington

A method and system acquires cache line data associated with a load from respective hierarchical cache data storage components. As a part of the method and system, a store queue is accessed for one or more portions of a cache line associated with the load, and, if the one or more portions of the cache line is held in the store queue, the one or more portions of the cache line is stored in a load queue location associated with the load. The load is completed if the one or more portions of the cache line stored in the load queue location includes all portions of the cache line associated with the load.

Systems and methods for acquiring data for loads at different access times from hierarchical sources using a load queue as a temporary storage buffer and completing the load early

Methods for read after write forwarding using a virtual address are disclosed. A method includes determining when a virtual address has been remapped from corresponding to a first physical address to a second physical address and determining if all stores occupying a store queue before the remapping have been retired from the store queue. Loads that are younger than the stores that occupied the store queue before the remapping are prevented from being dispatched and executed until the stores that occupied the store queue before the remapping have left the store queue and become globally visible.

Systems and methods for faster read after write forwarding using a virtual address

A method for acquiring cache line data associated with a load from respective hierarchical cache data storage components. As a part of the method, a store queue is accessed for one or more portions of a cache line associated with a load, and, if the one or more portions of the cache line is held in the store queue, the one or more portions of the cache line is stored in a load queue location associated with the load. The load is completed if the one or more portions of the cache line stored in the load queue location includes all portions of the cache line associated with the load.

An embodiment of the present invention includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. At least some of the active memory operations access the memory in an execution order that is different from the program order. The circuit includes a first memory that caches data accessed by the memory operations. This memory is partitioned into N banks. Checkpoint entries, which are stored in a second memory also partitioned into N banks, are associated with each trace. Each entry refers to a checkpoint location in the first memory. A sub-circuit receives rollback requests and responds by overwriting checkpoint locations. Each of the N memory units consisting of a bank in the first memory and the corresponding bank in the second memory may be rolled back independently and concurrently with other memory units.

Cache rollback acceleration via a bank based versioning cache ciruit

This invention includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. The memory operations being executed form a set of active memory operations that have a predefined program order among them and corresponding ordering constraints. At least some of the active memory operations access the memory in an execution order that is different from the program order. Checkpoint entries are associated with each trace. Each entry refers to a checkpoint location. Memory operation ordering entries correspond to each one of the active memory operations. Violations of the ordering constraints result in overwriting the checkpoint locations associated with the selected trace as well as the checkpoint locations associated with traces that are younger than the selected trace.

Data cache rollbacks for failed speculative traces with memory operations

A circuit for tracking memory operations with trace-based execution is disclosed. Each trace includes a sequence of operations that includes zero or more of the memory operations. The memory operations being executed form a set of active memory operations that have a predefined program order among them. At least some of the active memory operations access the memory in an execution order that is different from the program order. Checkpoint entries are associated with each trace. Each entry refers to a checkpoint location. Executing one of the active memory operations updates a checkpoint location. During the operation of the circuit, none of the operations of a given trace has any effect on the execution unit's architectural state prior to committing that trace. Each trace becomes eligible for commitment after all operations in the trace complete executing. After the trace is committed, all of the checkpoint entries associated with the trace are invalidated.

Trace based deallocation of entries in a versioning cache circuit

A processor includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. The memory operations being executed form a set of active memory operations that have a predefined program order among them. At least some of the active memory operations access the memory in an execution order that is different from the program order. During the operation of the circuit, none of the operations of a given trace has any effect on the execution unit's architectural state prior to committing that trace. Each trace becomes eligible for commitment after all operations in the trace complete executing. The circuit also includes a sub-circuit that holds memory operation ordering information corresponding to the active memory operations. The sub-circuit detects violations of ordering constraints. After each trace is committed, the sub-circuit invalidates all of the memory operation ordering information associated with the trace.

Memory ordering queue/versioning cache circuit

An embodiment of the present invention includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. The memory operations being executed form a set of active memory operations that have a predefined program order among them and corresponding ordering constraints. At least some of the active memory operations access the memory in an execution order that is different from the program order. Checkpoint entries are associated with each trace. Violations of the ordering constraints may be signaled too late to prevent an update of the cached data associated with the memory operations. A sub-circuit detects this condition and invalidates the checkpoint locations indicated by the checkpoint entries associated with the trace experiencing the violation and all younger traces.

Checking for a memory ordering violation after a speculative cache write

An embodiment of the present invention includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. The memory operations being executed form a set of active memory operations that have a predefined program order among them and corresponding ordering constraints. At least some of the active memory operations access the memory in an execution order that is different from the program order. Checkpoint entries are associated with each trace. When a memory operation attempts to update a cache line that may not be updated, the circuit attempts to upgrade the cache line. If this fails, a rollback request is generated that indicates the trace involved. The checkpoint locations associated with the indicated trace are overwritten along with those locations associated with all younger traces.

Rolling back a speculative update of a non-modifiable cache line

This invention includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. Traces execute atomically and become eligible for commitment after all the operations in the trace have executed. The memory operations being executed form a set of active memory operations that have a predefined program order among them and corresponding ordering constraints. At least some of the active memory operations access the memory in an execution order that is different from the program order. Checkpoint entries are associated with each trace. Each entry refers to a checkpoint location. Memory operation ordering entries correspond to each one of the active memory operations. Rollback requests result in overwriting the checkpoint locations associated with the selected trace as well as the checkpoint locations associated with traces that are younger than the selected trace.

Trace based rollback of a speculatively updated cache

An embodiment of the present invention includes a circuit for tracking memory operations with trace-based execution. Each trace includes a sequence of operations that includes zero or more of the memory operations. The memory operations being executed form a set of active memory operations that have a predefined program order among them and corresponding ordering constraints. At least some of the active memory operations access the memory in an execution order that is different from the program order. Checkpoint entries are associated with each trace. There is a one-to-one correspondence between checkpoint entries and memory operation ordering entries. Each checkpoint entry refers to a checkpoint location. Rollback requests cause the circuit to overwrite checkpoint entries associated with the corresponding trace.

Memory ordering queue tightly coupled with a versioning cache circuit

A processor including an integrated system interface unit configured to manage multiple I/O interfaces and multiple protocols. A processor includes a plurality of processing cores, a cache comprising a plurality of banks, and a system interface unit coupled to the processing cores and the cache. The system interface unit includes an inbound unit configured to receive inbound transactions from a first I/O unit and a second I/O unit, and an outbound unit configured to convey outbound transactions to either the first I/O unit or the second I/O unit. Each of the first and second I/O units is configured to support different protocols. Prior to conveying transaction data to the system interface, the first I/O unit and second I/O units reformat transaction data to conform to a common format. The system interface receives and stores transaction data in either queues dedicated for cacheable transactions or queues dedicated for non-cacheable transactions. In addition, each of the I/O units may also indicate in the common format whether a given transaction is to be ordered with respect to other transactions. The system interface may separately store ordered transactions from those which are non-ordered.

Growing community of inventors

Oakland, CA, United States of America

Paul G Chan