Increment update in an SCI based system

A multi-node system that performs an update operation on a memory sharing list comprised of a plurality of nodes, wherein the sharing list has a sequential arrangement of the nodes, wherein each node on the sharing list is storing in memory a copy of a memory data, the system comprising:

• means for issuing an update command for the update operation from a first node in the sharing list to the remaining nodes in the sharing list;
• means for using a data packet to distribute the command for the update operation throughout the system;
• means for preventing a node of the plurality of nodes from rolling out of the sharing list before the node receives the update command;
• and
• means for maintaining the first node at a head position in the sharing list;
• wherein the system is a SCI multi-node system, the memory is a cache, and the memory data is a memory line, and the means for preventing further comprises means for toggling a phase value of each node in the list as each node is incremented by the update command issued by the first node.

A method for performing an update operation on a sharing list comprised of a plurality of nodes in a SCI multi-node system, wherein the sharing list has a sequential arrangement of the nodes, wherein each node is storing in cache a copy of a memory line, the method comprising the steps of:

• issuing an update command from a first node in the sharing list to the remaining nodes in the sharing list, including issuing an increment command from the first node to the next node of the list;
• using a data packet to distribute the command for the update operation throughout the system;
• receiving, by a node of the plurality of nodes, the increment command from the first node;
• updating the cache of the node according to the increment command;
• sending, by the node, a reply back to the first node;
• preventing a node of the plurality of nodes from rolling out of the sharing list before the node receives the update command;
• and
• maintaining the first node at a head position in the sharing list;
• wherein the step of preventing comprises the step of toggling a phase value of each node in the list as each node is incremented by the update command issued by the first node.

A SCI multi-node system that performs an update operation on a sharing list comprised of a plurality of nodes, wherein the sharing list has a sequential arrangement of the nodes, wherein each node is storing in cache a copy of a memory line, the system comprising:

• means for issuing an update command from a first node in the sharing list to the remaining nodes in the sharing list, including means for issuing an increment command from the first node to the next node of the list;
• means for receiving, by a node of the plurality of nodes, the increment command from the first node;
• means for updating the cache of the node according to the increment command;
• sending, by the node, a reply back to the first node;
• means for preventing a node of the plurality of nodes from rolling out of the sharing list before the node receives the update command;
• and
• means for maintaining the first node at a head position in the sharing list;
• wherein the means for preventing further comprises means for toggling a phase value of each node in the list as each node is incremented by the update command issued by the first node.