A processing unit connected via a system fabric to multiple processing units calls a first single command in a bus protocol that allows sampling over the system fabric of the capability of snoopers distributed across the processing units to handle an interrupt. The processing unit, in response to detecting at least one first selection of snoopers with capability to handle the interrupt, calling a second single command in the bus protocol to poll the first selection of snoopers over the system fabric for an availability status. The processing unit, in response to detecting at least one second selection of snoopers respond with the available status indicating an availability to handle the interrupt, assigning a single snooper from among the second selection of snoopers to handle the interrupt by calling a third single command in the bus protocol.

A technique for handling interrupts in a data processing system includes receiving, by an interrupt routing controller (IRC), an event routing message (ERM) that includes an event source number for a notification source with an unserviced interrupt. In response to receiving the ERM, the IRC builds an event notification message (ENM) based on the event source number. The IRC determines a scope for the ENM based on an event target group (ETG) associated with the event source number. The IRC issues the ENM to an interrupt presentation controller (IPC) at the scope associated with the ETG.

A processing unit connected via a system fabric to multiple processing units calls a first single command in a bus protocol that allows sampling over the system fabric of the capability of snoopers distributed across the processing units to handle an interrupt. The processing unit, in response to detecting at least one first selection of snoopers with capability to handle the interrupt, calling a second single command in the bus protocol to poll the first selection of snoopers over the system fabric for an availability status. The processing unit, in response to detecting at least one second selection of snoopers respond with the available status indicating an availability to handle the interrupt, assigning a single snooper from among the second selection of snoopers to handle the interrupt by calling a third single command in the bus protocol.

A computing system may implement a low priority arbitration interrupt method that includes receiving a message signaled interrupt (MSI) message from an input output hub (I/O hub) transmitted over an interconnect fabric, selecting a processor to interrupt from a cluster of processors based on arbitration parameters, and communicating an interrupt service routine to the selected processor, wherein the I/O hub and the cluster of processors are located within a common domain.

A technique for handling interrupts in a data processing system includes receiving, by an interrupt routing controller (IRC), an event routing message (ERM) that includes an event source number for a notification source with an unserviced interrupt. In response to receiving the ERM, the IRC builds an event notification message (ENM) based on the event source number. The IRC determines a scope for the ENM based on an event target group (ETG) associated with the event source number. The IRC issues the ENM to an interrupt presentation controller (IPC) at the scope associated with the ETG.

A technique for handling interrupts in a data processing system includes receiving, by an interrupt routing controller (IRC), an event routing message (ERM) that includes an event source number for a notification source with an unserviced interrupt. In response to receiving the ERM, the IRC builds an event notification message (ENM) based on the event source number. The IRC determines a scope for the ENM based on an event target group (ETG) associated with the event source number. The IRC issues the ENM to an interrupt presentation controller (IPC) at the scope associated with the ETG.

A technique for handling interrupts in a data processing system includes receiving, by an interrupt routing controller (IRC), an event routing message (ERM) that includes an event source number for a notification source with an unserviced interrupt. In response to receiving the ERM, the IRC builds an event notification message (ENM) based on the event source number. The IRC determines a scope for the ENM based on an event target group (ETG) associated with the event source number. The IRC issues the ENM to an interrupt presentation controller (IPC) at the scope associated with the ETG.