Search results
Results from the WOW.Com Content Network
Idle is a state that a computer processor is in when it is not being used by any program. Every program or task that runs on a computer system occupies a certain amount of processing time on the CPU. If the CPU has completed all tasks it is idle. Modern processors use idle time to save power.
In Windows NT operating systems, the System Idle Process contains one or more kernel threads which run when no other runnable thread can be scheduled on a CPU. In a multiprocessor system, there is one idle thread associated with each CPU core. For a system with hyperthreading enabled, there is an idle thread for each logical processor.
For premium support please call: 800-290-4726 more ways to reach us
For example, one can interpret a load average of "1.73 0.60 7.98" on a single-CPU system as: During the last minute, the system was overloaded by 73% on average (1.73 runnable processes, so that 0.73 processes had to wait for a turn for a single CPU system on average). During the last 5 minutes, the CPU was idling 40% of the time, on average.
For example, hardware timers send interrupts to the CPU at regular intervals. Most operating systems execute a HLT instruction when there is no immediate work to be done, putting the processor into an idle state. In Windows NT, for example, this instruction is run in the "System Idle Process". On x86 processors, the opcode of HLT is 0xF4.
In many applications, the CPU and other components are idle much of the time, so idle power contributes significantly to overall system power usage. When the CPU uses power management features to reduce energy use, other components, such as the motherboard and chipset, take up a larger proportion of the computer's energy.
CPU Idle: 0x05: Requests system suspend. 0) Clock halted until timer tick interrupt. 1) Slow clock [1] CPU Busy: 0x06: Driver tells system APM to restore clock speed of the CPU. Set Power State: 0x07: Set system or device into Suspend/Standby/Off state. Enable/Disable Power Management: 0x08: Restore APM BIOS Power-On Defaults: 0x09: Get Power ...
ACPI 1.0 (1996) defines a way for a CPU to go to idle "C states", but defines no frequency-scaling system.. ACPI 2.0 (2000) introduces a system of P states (power-performance states) that a processor can use to communicate its possible frequency–power settings to the OS.