Managing efficient selection of a particular processor thread for handling an interrupt

A system comprising:

• a particular processing unit, of a plurality of processing units connected via a system fabric;
• the processing unit, in response to receiving, by a particular snooper of the particular processing unit, a first single bus command in a bus protocol that allows sampling over the system fabric of the capability of a plurality of snoopers to handle an interrupt, for returning, by the particular snooper, a first response indicating the capability of the particular snooper to handle the interrupt, wherein each of the plurality of processing units comprises a respective snooper from among the plurality of snoopers distributed across the plurality of processing units, wherein each respective snooper of the plurality of snoopers controls assignment of interrupts to one or more separate selections of processor threads distributed in each of the plurality of processing units;
• the processing unit, in response to receiving, by the particular snooper, a second single bus command in the bus protocol to poll a first selection of snoopers indicating capability of the plurality of snoopers for an availability status to service a criteria specified in the second single bus command, for returning, by the particular snooper, a second response indicating the availability of the particular snooper to service the criteria;
• and
• the processing unit, in response to receiving, by the particular snooper, a third single bus command in the bus protocol to direct the particular snooper to handle the interrupt, for assigning, by the particular snooper, the interrupt to a particular processor thread of a respective selection of the one or more separate selections of processors threads distributed in the particular processing unit.

A computer program product comprising one or more computer-readable storage devices and program instructions, stored on at least one of the one or more storage devices, the stored program instructions comprising:

• program instructions, in response to receiving, by a particular snooper of a particular processing unit of a plurality of processing units connected via a system fabric, a first single bus command in a bus protocol that allows sampling over the system fabric of the capability of a plurality of snoopers to handle an interrupt, to return, by the particular snooper, a first response indicating the capability of the particular snooper to handle the interrupt, wherein each of the plurality of processing units comprises a respective snooper from among the plurality of snoopers distributed across the plurality of processing units, wherein each respective snooper of the plurality of snoopers controls assignment of interrupts to one or more separate selections of processor threads distributed in each of the plurality of processing units;
• program instructions, in response to receiving, by the particular snooper, a second single bus command in the bus protocol to poll a first selection of snoopers indicating capability of the plurality of snoopers for an availability status to service a criteria specified in the second single bus command, to return, by the particular snooper, a second response indicating the availability of the particular snooper to service the criteria;
• and
• program instructions, in response to receiving, by the particular snooper, a third single bus command in the bus protocol to direct the particular snooper to handle the interrupt, to assign, by the particular snooper, the interrupt to a particular processor thread of a respective selection of the one or more separate selections of processors threads distributed in the particular processing unit.