Patent ID: 7228441

Claim:
In a computer system comprising: a plurality of computers operating as servers each computer having at least one processing unit, a memory coupled to said at least one processing unit, logic circuits coupled to said processing unit contributing to operation of said computer system, and an activity monitor identifying a level of activity information for said at least one processor, a method for controlling the operating mode and as a result the power consumption each of said plurality of computers in said computer system between a plurality of operating modes each having a different electrical power consumption levels or ranges; said method comprising: configuring each of said computers to be operable in at least: (i) a first mode having a first maximum performance level and a first power consumption rate, (ii) a third mode having a third maximum performance level lower than said first maximum performance level and a third power consumption rate lower than said first power consumption rate, and (iii) a second mode having a second maximum performance level intermediate between said first maximum performance level and said third maximum performance level and a second power consumption rate intermediate between said first power consumption rate and said third power consumption rate; generating, by each of said plurality of computers, a level of activity information; communicating the level of activity information from each of said plurality of computers to a power manager computer, the power manager computer being one of the plurality of computers or a different computer; receiving by the power manager computer said level of activity information from each of said plurality of computers; analyzing by said power manager computer said plurality of received level of activity information; determining by said power manager computer an operating mode for each of said computers selected from said first mode, said second mode, and third mode based on said analyzed activity information and predetermined policies; generating commands to each of said plurality of computers directing each of said plurality of computers to operate in said determined operating mode; and while operating in a first selected operating mode exhibiting that first selected mode's characteristic power consumption range, (i) monitoring said computer system to detect the occurrence or non-occurrence of a first event; and (ii) transitioning said computer system from said first selected operating mode to a second selected operating mode exhibiting that second selected operating mode's power consumption range.