Probe interrupt delivery

Abstract

Systems, apparatuses, and methods for routing interrupts on a coherency probe network are disclosed. A computing system includes a plurality of processing nodes, a coherency probe network, and one or more control units. The coherency probe network carries coherency probe messages between coherent agents. Interrupts that are detected by a control unit are converted into messages that are compatible with coherency probe messages and then routed to a target destination via the coherency probe network. Interrupts are generated with a first encoding while coherency probe messages have a second encoding. Cache subsystems determine whether a message received via the coherency probe network is an interrupt message or a coherency probe message based on an encoding embedded in the received message. Interrupt messages are routed to interrupt controller(s) while coherency probe messages are processed in accordance with a coherence probe action field embedded in the message.

What is claimed is: 
     
         1 . A system comprising:
 one or more processing nodes;   a control unit; and   a coherency probe network configured to convey coherency probe messages between the one or more processing nodes and the control unit;   wherein the control unit is configured to:
 generate an interrupt message that is compatible with a coherency probe message, responsive to detecting an interrupt; and 
 send, via the coherency probe network, the interrupt message on a path to a target. 
   
     
     
         2 . The system as recited in  claim 1 , wherein the control unit is further configured to:
 generate a first encoding for coherency probe messages;   embed the first encoding in a given field of coherency probe messages sent on the coherency probe network;   generate a second encoding for interrupt messages, wherein the second encoding is different from the first encoding; and   embed the second encoding in the given field of interrupt messages sent on the coherency probe network.   
     
     
         3 . The system as recited in  claim 1 , wherein the interrupt message includes an encoding in a response field that indicates no response needs to be sent. 
     
     
         4 . The system as recited in  claim 1 , wherein the system further comprises one or more cache subsystems, wherein each cache subsystem is configured to determine whether a received message is a coherency probe message or an interrupt message based on an embedded encoding. 
     
     
         5 . The system as recited in  claim 4 , wherein each cache subsystem is further configured to broadcast an interrupt message to a plurality of processor cores of a respective node responsive to determining that the received message is an interrupt message. 
     
     
         6 . The system as recited in  claim 1 , wherein fields of the interrupt message are aligned to match fields of the coherency probe message. 
     
     
         7 . The system as recited in  claim 1 , wherein the control unit is further configured to encode a coherency probe action field of the interrupt message with an interrupt delivery indicator. 
     
     
         8 . A method comprising:
 generating, by a control unit, an interrupt message that is compatible with a coherency probe message responsive to detecting an interrupt; and   sending, via a coherency probe network, the interrupt message on a path to a target, wherein the coherency probe network is configured to carry coherency probes between one or more processing nodes and the control unit.   
     
     
         9 . The method as recited in  claim 8 , further comprising:
 generating a first encoding for coherency probe messages;   embedding the first encoding in a given field of coherency probe messages sent on the coherency probe network;   generating a second encoding for interrupt messages, wherein the second encoding is different from the first encoding; and   embedding the second encoding in the given field of interrupt messages sent on the coherency probe network.   
     
     
         10 . The method as recited in  claim 8 , wherein the interrupt message includes an encoding in a response field that indicates no response needs to be sent. 
     
     
         11 . The method as recited in  claim 8 , further comprising determining, by a cache subsystem, whether a received message is a coherency probe message or an interrupt message based on an embedded encoding. 
     
     
         12 . The method as recited in  claim 11 , further comprising broadcasting, by the cache subsystem, an interrupt message to a plurality of processor cores of a respective node responsive to determining that the message is an interrupt message. 
     
     
         13 . The method as recited in  claim 8 , wherein fields of the interrupt message are aligned to match fields of the coherency probe message. 
     
     
         14 . The method as recited in  claim 8 , further comprising encoding a coherency probe action field of the interrupt message with an interrupt delivery indicator. 
     
     
         15 . An apparatus comprising:
 a plurality of processor cores; and   a cache subsystem;   wherein the apparatus is configured to:
 generate an interrupt message that is compatible with a coherency probe message responsive to detecting an interrupt; and 
 send, via a coherency probe network, the interrupt message on a path to a target device, wherein the coherency probe network is configured to carry coherency probes between the apparatus and one or more coherent agents. 
   
     
     
         16 . The apparatus as recited in  claim 15 , wherein the apparatus is further configured to:
 generate a first encoding for coherency probe messages;   embed the first encoding in a given field of coherency probe messages sent on the coherency probe network;   generate a second encoding for interrupt messages, wherein the second encoding is different from the first encoding; and   embed the second encoding in the given field of interrupt messages sent on the coherency probe network.   
     
     
         17 . The apparatus as recited in  claim 15 , wherein the interrupt message includes an encoding in a response field that indicates no response needs to be sent. 
     
     
         18 . The apparatus as recited in  claim 15 , wherein the apparatus is further configured to determine whether a received message is a coherency probe message or an interrupt message based on an embedded encoding. 
     
     
         19 . The apparatus as recited in  claim 18 , wherein the apparatus is further configured to broadcast an interrupt message to a plurality of processor cores of a respective node responsive to determining that the received message is an interrupt message. 
     
     
         20 . The apparatus as recited in  claim 15 , wherein fields of the interrupt message are aligned to match fields of the coherency probe message.