Multi-node computer system implementing global access state dependent transactions

A node for use in a multi-node system, the node comprising:

• a plurality of devices including a memory subsystem, one or more active devices, and an interface configured to send and receive coherency messages on an inter-node network coupling nodes in the multi-node system;
• and
• an address network configured to communicate address packets between the plurality of devices;
• wherein a given active device having an ownership responsibility for a coherency unit is configured to respond to certain access right requests;
• wherein in response to receiving a coherency message on the inter-node network requesting an access right to a coherency unit, the interface is configured to send a first type of address packet on the address network if the coherency unit is in a modified global access state in the node and to send a second type of address packet on the address network if the coherency unit is not in the modified global access state in the node;
• and
• wherein if the given active device has an ownership responsibility for the coherency unit, the given active device is configured to ignore the second type of address packet and to respond to the first type of address packet.

A system, comprising:

• means for communicating coherency messages between a plurality of nodes;
• a node included in the plurality of nodes, wherein the node includes a plurality of devices and means for communicating address packets between the plurality of devices, wherein the plurality of devices includes one or more active devices and means for sending and receiving coherency messages on the means for communicating coherency messages;
• and
• an additional node included in the plurality of nodes;
• wherein a given active device having an ownership responsibility for a coherency unit is configured to respond to certain access right requests;
• wherein in response to receiving a coherency message requesting an access right to a coherency unit via the means for communicating coherency messages between the plurality of nodes, the means for sending and receiving coherency messages sends a first type of address packet on the means for communicating address packets if a maximum allowable access right of the plurality of devices to the coherency unit is write access and sends a second type of address packet on the means for communicating address packets if the maximum allowable access right of the plurality of devices to the coherency unit is not write access;
• and
• wherein if the given active device has an ownership responsibility for the coherency unit, the given active device is configured to ignore the second type of address packet and to respond to the first type of address packet.