Abstract: A method and system for energy management in a simultaneous multi-threaded (SMT) processing system including per-thread device usage monitoring provides control of energy usage that accommodates thread parallelism. Per-device usage information is measured and stored on a per-thread basis, so that upon a context switch, the previous usage evaluation state can be restored. The per-thread usage information is used to adjust the thresholds of device energy management decision control logic, so that energy use can be managed with consideration as to which threads will be running in a given execution slice. A device controller can then provide for per-thread control of attached device power management states without intervention by the processor and without losing the historical evaluation state when a process is switched out. The device controller may be a memory controller and the controlled devices memory modules or banks within modules if individual banks can be power-managed.

Abstract: A method and system for power management including local bounding of device group power consumption provides the responsiveness of local power control while meeting global system power consumption and power dissipation limits. At the system level, a global power bound is determined and divided among groups of devices in the system so that local bounds are determined that meet the global system bound. The local bounds are communicated to device controllers associated with each group of devices and the device controllers control the power management states of the associated devices in the group to meet the local bound. Thus, by action of all of the device controllers, the global bound is met. The controllers may be memory controllers and the devices memory modules, or the devices may be other devices within a processing system having associated local controllers.

Abstract: A method and system for energy management via energy-aware process scheduling provides per-process energy use/power dissipation control to manage system energy requirements and thermal conditions without throttling overall system performance. Use of energy by a particular process is measured or is estimated from resource requirements that are determined by the operating system or reported by the application owning the process. The scheduler then determines whether or not to allocate execution slices to the process in conformity with the measured or estimated energy requirements of the process. The scheduler may insert “idle” execution slices to reduce energy use/power dissipation or may prefer low energy-use processes over high energy-use processes. Pragmatic faults may be issued as warnings from the operating system to an application to indicate that energy requirements need to be curtailed.

Abstract: A method and system for power management including device controller-based device use evaluation and power-state control provides improved performance in a power-managed processing system. Per-device usage information is measured and evaluated during process execution and is retrieved from the device controller upon a context switch, so that upon reactivation of the process, the previous usage evaluation state can be restored. The device controller can then provide for per-process control of attached device power management states without intervention by the processor and without losing the historical evaluation state when a process is switched out. The device controller can control power-saving states of connected devices in conformity with the usage evaluation without processor intervention and across multiple process execution slices. The device controller may be a memory controller and the controlled devices memory modules or banks within modules if individual banks can be power-managed.