Timer coalescing
Operating system feature to reduce CPU idle time
Timer coalescing is a computer system energy-saving technique that reduces central processing unit (CPU) power consumption by reducing the precision of software timers used for synchronization of process wake-ups, minimizing the number of times the CPU is forced to perform the relatively power-costly operation of entering and exiting idle states.[1]
Implementations of timer coalescing
- The Linux kernel gained support for deferrable timers in 2.6.22,[2][3] and controllable "timer slack" for threads in 2.6.28 allowing timer coalescing.[4][5]
- Timer coalescing has been a feature of Microsoft Windows from Windows 7 onward.[6]
- Apple's XNU kernel based OS X gained support as of OS X Mavericks.[7][8]
- FreeBSD supports it since September 2010.[9]
See also
- Advanced Configuration and Power Interface (ACPI)
- Advanced Programmable Interrupt Controller (APIC)
- High Precision Event Timer (HPET)
- HLT (x86 instruction)
- Interrupt coalescing
- Programmable interval timer
- Time Stamp Counter (TSC)
References
- ^ Anderson, Nate (June 11, 2013). "How OS X "Mavericks" works its power-saving magic". Ars Technica. Retrieved 2014-03-22.
- ^ "Linux Kernel 2 6 22". kernelnewbies.org. Retrieved 2014-03-22.
- ^ "Add support for deferrable timers". 2007-05-08. Retrieved 2014-03-22.
- ^ "time(7) - Linux manual page". Man7.org. Retrieved 2014-03-24.
- ^ "prctl(2) - Linux manual page". Man7.org. Retrieved 2014-03-24.
- ^ "Windows Timer Coalescing". Microsoft. January 20, 2009. Retrieved 2009-04-21.
- ^ "OS X Mavericks - Advanced Technologies". Apple Inc. Retrieved 2014-03-22.
- ^ "OS X Mavericks: Core Technologies Overview" (PDF). Apple, Inc. June 10, 2013. Archived from the original (PDF) on June 26, 2013. Retrieved 2013-06-10.
- ^ "Refactor timer management code". 13 September 2010.
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