System and method for controlling processor low power states

Abstract

A next idle state for a processor in a system may be determined based on a previous idle period and a previous idle state. The next idle state for the processor may also be determined based on times when interrupts are generated by devices in the system.

1 . A method, comprising:
 determining a possible next idle state for a processor by comparing a previous idle period of the processor and threshold times associated with available idle states.   
     
     
         2 . The method of  claim 1 , wherein the possible next idle state is to be verified against a probability that the possible next idle state is to be selected as a next idle state. 
     
     
         3 . The method of  claim 2 , wherein each of the available idle states is associated with a probability that it is selected as the next idle state. 
     
     
         4 . The method of  claim 3 , wherein the probability that an idle state is selected as the next idle state is adjusted after the possible next idle state is determined. 
     
     
         5 . The method of  claim 4 , wherein when a first idle state is determined to be the possible next idle state, the probability that the first idle state is selected as the next idle state is increased. 
     
     
         6 . The method of  claim 5 , wherein when a second idle state is determined not to be the possible next idle state, the probability that the second idle state is selected as the next idle state is decreased. 
     
     
         7 . The method of  claim 6 , wherein when the probability that the first idle state is selected is above a threshold, the next idle state is the first idle state. 
     
     
         8 . The method of  claim 7 , wherein the threshold is 50 percent. 
     
     
         9 . The method of  claim 7 , wherein when the probability that the first idle state is selected is below a threshold, the next idle state is determined by comparing the first idle state with a previous idle state. 
     
     
         10 . The method of  claim 9 , wherein when the first idle state is to consume more power than the previous idle state, the next idle state is an idle state that is to consume less power than the first idle state. 
     
     
         11 . The method of  claim 9 , wherein when the first idle state is to consume less power than the previous idle state, the next idle state is an idle state that is to consume more power than the first idle state. 
     
     
         12 . A system, comprising:
 means for determining a possible next idle state;   means for adjusting selection states associated with available idle states including the possible next idle state, wherein a selection state corresponds to a probability that an associated idle state is selected as a next idle state; and   means for determining the next idle state based on the possible next idle state and the adjusted selection state associated with the possible next idle state.   
     
     
         13 . The system of  claim 12 , wherein means for adjusting the selection states associated with the available idle states comprises:
 means for determining whether to keep a selection state at a current level, to increase the selection state to a next higher level, or to decrease the selection state to a next lower level.   
     
     
         14 . The system of  claim 13 , wherein the possible next idle state is determined using a previous idle period and threshold times associated with the available idle states. 
     
     
         15 . The system of  claim 14 , wherein when the selection state associated with the possible next idle state corresponds to a probability of more than 50 percent, the possible next idle state is selected as the next idle state. 
     
     
         16 . The system of  claim 14 , wherein when the selection state associated with the possible next idle state corresponds to a probability of less than 50 percent, a previous idle state is used to determine the next idle state. 
     
     
         17 . An article of manufacture contained on a tangible embodied computer readable medium including data that, when accessed by a machine, cause the machine to performs operations comprising:
 determining a possible next idle state for a processor based on a previous idle period of the processor and threshold times associated with available idle states; and   determining a next idle state based on the possible next idle state and a probability that the possible next idle state is to be selected as a next idle state.   
     
     
         18 . The article of manufacture of  claim 17 , wherein there are one or more idle states, and wherein each of the idle states is associated with a probability that it is selected as the next idle state. 
     
     
         19 . The article of manufacture of  claim 18 , wherein the probability that an idle state is selected as the next idle state is adjusted after the possible next idle state is determined. 
     
     
         20 . The article of manufacture of  claim 19 ,
 wherein when a first idle state is determined to be the possible next idle state, the probability that the first idle state is selected as the next idle state is increased, and   wherein when a second idle state is determined not to be the possible next idle state, the probability that the second idle state is selected as the next idle state is decreased.