摘要:
A conflict resolution technique provides consistency such that all conflicts can be detected by at least one of the conflicting requestors if each node monitors all requests after that node has made its own request. If a line is in the Exclusive, Modified or Forward state, conflicts are resolved at the node holding the unique copy. The winner of the conflict resolution, and possibly the losers, report the conflict to the home node, which pairs conflict reports and issues forwarding instructions to assure that all requesting nodes eventually receive the requested data. If a requested cache line is either uncached or present only in the Shared state, the home node provides a copy of the cache node and resolves conflicts. In one embodiment, a blackout period after all responses until an acknowledgement message has been received allows all conflicting nodes to be aware of conflicts in which they are involved.
摘要:
A conflict resolution technique provides consistency such that all conflicts can be detected by at least one of the conflicting requestors if each node monitors all requests after that node has made its own request. If a line is in the Exclusive, Modified or Forward state, conflicts are resolved at the node holding the unique copy. The winner of the conflict resolution, and possibly the losers, report the conflict to the home node, which pairs conflict reports and issues forwarding instructions to assure that all requesting nodes eventually receive the requested data. If a requested cache line is either uncached or present only in the Shared state, the home node provides a copy of the cache node and resolves conflicts. In one embodiment, a blackout period after all responses until an acknowledgement message has been received allows all conflicting nodes to be aware of conflicts in which they are involved.
摘要:
A conflict resolution technique provides consistency such that all conflicts can be detected by at least one of the conflicting requestors if each node monitors all requests after that node has made its own request. If a line is in the Exclusive, Modified or Forward state, conflicts are resolved at the node holding the unique copy. The winner of the conflict resolution, and possibly the losers, report the conflict to the home node, which pairs conflict reports and issues forwarding instructions to assure that all requesting nodes eventually receive the requested data. If a requested cache line is either uncached or present only in the Shared state, the home node provides a copy of the cache node and resolves conflicts. In one embodiment, a blackout period after all responses until an acknowledgement message has been received allows all conflicting nodes to be aware of conflicts in which they are involved.
摘要:
A conflict resolution technique provides consistency such that all conflicts can be detected by at least one of the conflicting requestors if each node monitors all requests after that node has made its own request. If a line is in the Exclusive, Modified or Forward state, conflicts are resolved at the node holding the unique copy. The winner of the conflict resolution, and possibly the losers, report the conflict to the home node, which pairs conflict reports and issues forwarding instructions to assure that all requesting nodes eventually receive the requested data. If a requested cache line is either uncached or present only in the Shared state, the home node provides a copy of the cache node and resolves conflicts. In one embodiment, a blackout period after all responses until an acknowledgement message has been received allows all conflicting nodes to be aware of conflicts in which they are involved.
摘要:
A conflict resolution technique provides consistency such that all conflicts can be detected by at least one of the conflicting requestors if each node monitors all requests after that node has made its own request. If a line is in the Exclusive, Modified or Forward state, conflicts are resolved at the node holding the unique copy. The winner of the conflict resolution, and possibly the losers, report the conflict to the home node, which pairs conflict reports and issues forwarding instructions to assure that all requesting nodes eventually receive the requested data. If a requested cache line is either uncached or present only in the Shared state, the home node provides a copy of the cache node and resolves conflicts. In one embodiment, a blackout period after all responses until an acknowledgement message has been received allows all conflicting nodes to be aware of conflicts in which they are involved.
摘要:
Described herein is a cache coherency protocol having five states: Modified, Exclusive, Shared, Invalid and Forward (MESIF). The MESIF cache coherency protocol includes a Forward (F) state that designates a single copy of data from which further copies can be made. A cache line in the F state is used to respond to request for a copy of the cache line. In one embodiment, the newly created copy is placed in the F state and the cache line previously in the F state is put in the Shared (S) state, or the Invalid (I) state. Thus, if the cache line is shared, one shared copy is in the F state and the remaining copies of the cache line are in the S state.
摘要:
The cache coherency protocol described herein can be used to maintain a virtual model of a system, where the virtual model does not change as the system configuration changes. In general, the virtual model is based on the assumption that each node in the system can directly communicate with some number of other nodes in the system. In one embodiment, for each cache line, the address of the cache line is used to designate a node as the “home” node and all other nodes as “peer” nodes. The protocol specifies one set of messages for communication with the line's home node and another set of messages for communication with the line's peer nodes.
摘要:
Use of an import cache and/or an export directory with an agent within to respond to requests for data. The import cache stores data that has been imported through the agent. The export directory stores information related to data that has been exported through the agent. Because the import cache and the export directory only store data that has passed through the agent, not all data transferred within a system are tracked by a single import cache or export directory.
摘要:
The cache coherency protocol described herein can be used to maintain a virtual model of a system, where the virtual model does not change as the system configuration changes. In general, the virtual model is based on the assumption that each node in the system can directly communicate with some number of other nodes in the system. In one embodiment, for each cache line, the address of the cache line is used to designate a node as the “home” node and all other nodes as “peer” nodes. The protocol specifies one set of messages for communication with the line's home node and another set of messages for communication with the line's peer nodes.
摘要:
Use of an import cache and/or an export directory with an agent within to respond to requests for data. The import cache stores data that has been imported through the agent. The export directory stores information related to data that has been exported through the agent. Because the import cache and the export directory only store data that has passed through the agent, not all data transferred within a system are tracked by a single import cache or export directory.