timer coalescing
{{Short description|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.
== Implementations of timer coalescing ==
- The Linux kernel gained support for deferrable timers in 2.6.22, and controllable "timer slack" for threads in 2.6.28 allowing timer coalescing.
- Timer coalescing has been a feature of Microsoft Windows from Windows 7 onward.{{cite web
|url=http://www.microsoft.com/whdc/system/pnppwr/powermgmt/TimerCoal.mspx
|title=Windows Timer Coalescing
|date=January 20, 2009
|accessdate=2009-04-21
|publisher=Microsoft
}}
- Apple's XNU kernel based OS X gained support as of OS X Mavericks.
- FreeBSD supports it since September 2010.{{cite web|url=https://lists.freebsd.org/pipermail/svn-src-all/2010-September/028792.html
|title=Refactor timer management code
|date=13 September 2010
}}
See also
{{Div col}}
- 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)
{{Div col end}}
References
{{reflist | 30em | refs=
{{cite web | url = https://arstechnica.com/apple/2013/06/how-os-x-mavericks-works-its-power-saving-magic/
| title = How OS X "Mavericks" works its power-saving magic | author = Anderson, Nate | publisher = Ars Technica
| date = June 11, 2013 | accessdate=2014-03-22}}
{{cite web|url=https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6e453a67510a17f01b63835f18569e8c3939a38c
| title = Add support for deferrable timers | date = 2007-05-08 | accessdate=2014-03-22}}
{{cite web|url=http://kernelnewbies.org/Linux_2_6_22|title=Linux Kernel 2 6 22|publisher=kernelnewbies.org|accessdate=2014-03-22}}
{{cite web|url=https://www.apple.com/osx/preview/advanced-technologies.html|title=OS X Mavericks - Advanced Technologies
|publisher=Apple Inc.|accessdate=2014-03-22}}
{{cite web
|title = OS X Mavericks: Core Technologies Overview
|url = https://images.apple.com/osx/preview/docs/OSX_Mavericks_Core_Technology_Overview.pdf
|publisher = Apple, Inc.
|date = June 10, 2013
|accessdate = 2013-06-10
|url-status = dead
|archiveurl = https://web.archive.org/web/20130626042313/http://images.apple.com/osx/preview/docs/OSX_Mavericks_Core_Technology_Overview.pdf
|archivedate = June 26, 2013
}}
}}
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