Wait state
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A wait state is a delay experienced by a computer
Computer microprocessors generally run much faster than the computer's other subsystems, which hold the data the CPU reads and writes. Even memory, the fastest of these, cannot supply data as fast as the CPU could process it. In an example from 2011, typical PC processors like the
When the processor needs to access external memory, it starts placing the address of the requested information on the
Wait states are a pure waste of a processor's performance. Modern designs try to eliminate or hide them using a variety of techniques:
Energy conservation
Wait states can be used to reduce the energy consumption of a processor, by allowing the main processor clock to either slow down or temporarily pause during the wait state if the CPU has no other work to do. Rather than spinning uselessly in a tight loop waiting for data, sporadically reducing the clock speed in this manner helps to keep the processor core cool and to extend battery life in portable computing devices.
Alternative meaning on IBM mainframes
On
See also
- Bubble (computing)
- Cache coherence § Coherence protocols
- Consistency model
- Cache miss
- Multithreading (computer architecture)
References
- ^ "IBM Knowledge Center". www.ibm.com. 9 December 2016. Retrieved 14 April 2017.