Conserving power by reducing voltage supplied to an instruction-processing portion of a processor
View Patent ↗One embodiment of the present invention provides a system that facilitates reducing static power consumption of a processor. During operation, the system receives a signal indicating that instruction execution within the processor is to be temporarily halted. In response to this signal, the system halts an instruction-processing portion of the processor, and reduces the voltage supplied to the instruction-processing portion of the processor. Full voltage is maintained to a remaining portion of the processor, so that the remaining portion of the processor can continue to operate while the instruction-processing portion of the processor is in reduced power mode.
1. A method for reducing power consumption of a processor, comprising:
monitoring an execution pattern of the processor to determine whether processing can be suspended for an instruction-processing portion of the processor or whether the instruction-processing portion of the processor should remain fully active to process instructions;
if processing can be suspended for the instruction-processing portion of the processor,
saving state information from the instruction-processing portion of the processor to a second portion of the processor; and
reducing a voltage to the instruction-processing portion of the processor, but maintaining full voltage to the second portion of the processor.
2. The method of claim 1 , wherein reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to zero.
3. The method of claim 1 , wherein upon receiving a wakeup signal, the method further comprises:
restoring flail voltage to the instruction-processing portion of the processor;
restoring state information to the instruction-processing portion of the processor; and
resuming processing of computer instructions.
4. The method of claim 1 , wherein maintaining full voltage to the second portion of the processor involves maintaining full voltage to a snoop-logic portion of the processor, whereby the processor can continue to perform cache snooping operations while the instruction-processing portion of the processor is in the reduced power mode.
5. The method of claim 1 , further comprising reducing the voltage to a cache memory portion of the processor.
6. The method of claim 5 , further comprising writing cache memory data to main memory prior to reducing the voltage.
7. The method of claim 1 , wherein the second portion of the processor includes a control portion of the processor that includes interrupt and clock circuitry.
8. The method of claim 1 , wherein the second portion of the processor includes a cache memory portion of the processor.
9. The method of claim 1 , wherein saving state information involves saving state information to a main memory outside the processor.
10. An apparatus for reducing static power consumption of a processor, comprising:
a monitoring mechanism;
a saving mechanism coupled to the monitoring mechanism;
a voltage-adjusting mechanism coupled to the monitoring mechanism;
wherein the monitoring mechanism is configured to monitor an execution pattern of the processor to determine whether processing can be suspended for an instruction-processing portion of the processor or whether the instruction-processing portion of the processor should remain fully active to process instructions;
responsive to the monitoring mechanism determining that processing can be suspended for the instruction-processing portion of the processor,
the saving mechanism is configured to save state information from the instruction-processing portion of the processor to a second portion of the processor; and
the voltage-adjusting mechanism is configured to reduce a voltage to the instruction-processing portion of the processor, but maintain full voltage to the second portion of the processor.
11. The apparatus of claim 10 , wherein reducing the voltage supplied to the instruction-processing portion of the processor involves reducing the voltage to zero.
12. The apparatus of claim 10 , further comprising:
a voltage restoring mechanism configured to restore full voltage to the instruction-processing portion of the processor;
a state restoring mechanism configured to restore state information to the instruction-processing portion of the processor; and
a resuming mechanism configured to resume processing of computer instructions.
13. The apparatus of claim 10 , wherein maintaining full voltage to the second portion of the processor involves maintaining full voltage to a snoop-logic portion of the processor, whereby the processor can continue to perform cache snooping operations while the instruction-processing portion of the processor is in the reduced power mode.
14. The apparatus of claim 10 , wherein the voltage-adjusting mechanism is further configured to reduce the voltage to a cache memory portion of the processor.
15. The apparatus of claim 14 , further comprising a writing mechanism configured to write cache memory data to main memory prior to reducing the voltage.
16. The apparatus of claim 10 , wherein the second portion of the processor includes a control portion of the processor that includes interrupt circuitry and clock circuitry.
17. The apparatus of claim 10 , wherein the second portion of the processor includes a cache memory portion of the processor.
18. The apparatus of claim 10 , wherein the saving mechanism is configured to save state information to a main memory outside the processor.