Abstract: Systems, apparatuses, and methods for implementing a hierarchical scheduler. In various implementations, a processor includes a global scheduler, and a plurality of independent local schedulers with each of the local schedulers coupled to a plurality of processors. In one implementation, the processor is a graphics processing unit and the processors are computation units. The processor further includes a shared cache that is shared by the plurality of local schedulers. Each of the local schedulers also includes a local cache used by the local scheduler and processors coupled to the local scheduler. To schedule work items for execution, the global scheduler is configured to store one or more work items in the shared cache and convey an indication to a first local scheduler of the plurality of local schedulers which causes the first local scheduler to retrieve the one or more work items from the shared cache.

Abstract: Systems, apparatuses, and methods for implementing a message passing system to schedule work in a computing system. In various implementations, a processor includes a global scheduler, and a plurality of local schedulers with each of the local schedulers coupled to a plurality of processors. The processor further includes a shared cache that is shared by the plurality of local schedulers. Also, a plurality of mailboxes are implemented to enable communication between the local schedulers and the global scheduler. To schedule work items for execution, the global scheduler is configured to store one or more work items in the shared cache and store an indication in a mailbox for a first local scheduler of the plurality of local schedulers. Responsive to detecting the message in the mailbox, the first local scheduler identifies a location of the one or more work items in the shared cache and retrieves them for scheduling locally.