Importance

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Abstract

A computer system defines a 'fast write' protocol for performing certain write operations. Write operations include a particular encoding if they are to be performed using the fast write protocol. When the system interface within a node detects the particular encoding, the write operation is captured by the system interface. In addition, the data is transferred to the system interface from the processor performing the write operation. The data transfer is performed even if the node is not maintaining a coherency state for the affected coherency unit which is consistent with performing the write operation. Instead, the coherency activity employed to acquire the proper coherency state is initiated subsequent to or in parallel with the receipt of data from the processor. Because fast write operations are performed prior to acquiring write permission to the coherency unit, ordering with respect to other operations is not maintained. Therefore, the fast write protocol is not suitable for all write operations within the computer system. However, the protocol may be used to increase performance. For example, a group of writes enveloped by software synchronization operations appear to be ordered as a group with respect to operations outside of the synchronization. The performance gained by executing the group of writes using the fast write protocol may outweigh the system bandwidth and extra latency used to perform synchronization.

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First Claim