adaptive dynamic buffering system for power management in server clusters

Abstract

A system, method and computer program product for managing power consumption in a system comprising at least two computing devices. The at least two computing devices are organized as part of active computing device group or a ready computing device group, the ready computing devices configured into various modes of readiness including a standby mode, a hibernating mode, and a power-off mode. A control device receives obtained sensed parameters indicative of the processing load at the group of active computing devices and determines a “Readiness” index value representing a state of system readiness which is a function of a transition time parameter representing a time for moving one or more computing devices from the second group of ready computing devices to the first group of active devices in response to a service level violation. To achieve maximum power saving and yet meet various performance targets, the ready computing devices are dynamically allocated from amongst three states: standby, hibernating or power-off, based on the current readiness index value.

1 . A computer program product for managing power consumption in a system comprising at least two computing devices including a first group of active computing devices each adapted for processing a computational workload, the computer program comprising a computer readable medium having computer usable program code embodied therewith, the computer usable program code comprising:
 computer usable code configured to sense a state of processing operations at said active computing devices,   computer usable code configured to receive, at said control device, a signal requesting that additional computing devices from a second group of inactive computing devices be added to the first group of active computing devices, or that computing devices from the first group of active computing devices be placed in the second group of inactive computing devices according to said state of processing operations;   computer usable code configured to determine a system transition time TT value for moving one or more computing devices from the second group of ready computing devices to said first group of active devices, and comparing said TT value against a minimum value, M_min, representing a minimum acceptable delay time for switching a standby computing device from said second group of ready computing devices to said first group of active computing devices and, against a maximum value, M_max, representing a maximum delay interval when all computing devices are in a powered off state;   said computer usable code configured to enable the control device to further dynamically generate a readiness index parameter RI t  at a current time indicating a state of system readiness where RI t  is a real number from 0 to 1, where 0 represents minimum readiness and 1 represents maximum readiness, said RI t  calculated according to one of:   RI t =RI t−1 +(TT−M_min)/M_max, when increasing system readiness according to a predetermined system response time policy, or,   RI t =RI t−1 −(TT−M_min)/M_max, when decreasing system readiness according to a predetermined system response time policy, and, where RI t−1  is a RI value prior to said current time; and,   computer usable code configured to dynamically allocate one or more computing devices in said second group of ready computing devices in various stages of stand-by, hibernating and power-off readiness according to a value of said readiness index parameter, wherein   if RI=0, all N ready computing devices in the second group are in powered-off state where N=number of total ready computing devices in the second group; and,   if RI=1, all N ready computing devices in the second group are in one of: standby state or hibernating state;   wherein, a time it takes to bringing a computing device from said second group of ready computing device to an active readiness state in said first group is minimized, while maximizing energy savings in said system.   
   
   
       2 . The computer program product for managing power consumption as claimed in  claim 1 , wherein said dynamically allocating includes:
 providing a number N*(1−RI) of powered off computing devices in said second group;   providing a number N*RI/2 of standby computing devices in said second group; and, providing a number N*RI/2 of hibernating computing devices in said second group.