Managing execution of mixed workloads in a simultaneous multi-threaded (smt) enabled system

A simultaneous multi-thread (SMT) enabled processing system, comprising a plurality of processors each enabled for simultaneous execution of multiple hardware threads, wherein said plurality of processors include an exclusive set of processors to execute work on, comprising;

• a kernel, stored on a memory and operative to schedule a single-threaded (ST) workload on said exclusive set of processors by selecting only one hardware thread per processor within said exclusive set of processors to handle a separate one of said plurality of tasks of the ST workload while requiring the remaining hardware threads per processor within said exclusive set of processors to run in an idle process, further comprising:
• the kernel, operative to set a separate dispatcher for each hardware thread of said exclusive set of processors to only execute work on each local run queue associated with each said hardware thread of said exclusive set of processors;
• the kernel, operative to drain any tasks waiting on each local run queue associated with each said hardware thread of said exclusive set of processors;
• the kernel, operative to pass each said hardware thread of said exclusive set of processors to said idle process, wherein said idle process searches each local run queue and cedes each said hardware thread of said exclusive set of processors to a hypervisor while each local run queue associated with each hardware thread of said exclusive set of processors remains empty, wherein said hypervisor automatically returns each said hardware thread to said idle process while each local run queue associated with each said hardware thread of said exclusive set of processors remains empty;
• the kernel, operative to apply each separate task of said ST workload to a separate local run queue of each said selected one hardware thread per processor within said exclusive set of processors;
• the kernel, operative to send an interrupt to direct said hypervisor to return those selected one hardware thread per processor currently ceded to said hypervisor;
• and
• the kernel, responsive to detecting said remaining hardware threads ceded to said hypervisor, operative to place each of said remaining hardware threads in a snooze mode, wherein only a particular selection of interrupts awakens each hardware thread placed in snooze mode to return to said idle process.

A computer program product for managing a simultaneous multi-threaded (SMT) enabled processor system comprising a plurality of processors each activated to simultaneously execute a plurality of hardware threads, wherein said plurality of processors include an exclusive set of processors to execute work on, said computer program product tangibly embodied in a computer-readable storage medium and comprising computer executable instructions which cause a computer to:

• schedule a plurality of tasks of a single-threaded (ST) workload on said exclusive set of processors by selecting only one hardware thread per processor within said exclusive set of processors to handle a separate one of said plurality of tasks of said ST workload while requiring the remaining hardware threads per processor within said exclusive set of processors to run in an idle process, further comprising computer executable instructions which cause a computer to:
• set a separate dispatcher for each hardware thread of said exclusive set of processors to only execute work on each local run queue associated with each said hardware thread of said exclusive set of processors;
• drain any tasks waiting on each local run queue associated with each said hardware thread of said exclusive set of processors;
• pass each said hardware thread of said exclusive set of processors to said idle process, wherein said idle process searches each local run queue and cedes each said hardware thread of said exclusive set of processors to a hypervisor while each local run queue associated with each hardware thread of said exclusive set of processors remains empty, wherein said hypervisor automatically returns each said hardware thread to said idle process while each local run queue associated with each said hardware thread of said exclusive set of processors remains empty;
• apply each separate task of said ST workload to a separate local run queue of each said selected one hardware thread per processor within said exclusive set of processors;
• send an interrupt to direct said hypervisor to return those selected one hardware thread per processor currently ceded to said hypervisor;
• and
• responsive to detecting said remaining hardware threads ceded to said hypervisor, place each of said remaining hardware threads in a snooze mode, wherein only a particular selection of interrupts awakens each hardware thread placed in snooze mode to return to said idle process.