Hashed and Hierarchical Timing Wheels: Efficient Data Structures for Implementing a Timer Facility

Hashed and Hierarchical Timing Wheels: Efficient Data Structures for Implementing a Timer Facility (1996)

by George Varghese , Tony Lauck

Citations:

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Datum	Value	Source
TITLE	Hashed and Hierarchical Timing Wheels: Efficient Data Structures for Implementing a Timer Facility	user correction - Legacy Corrections
AUTHOR NAME	George Varghese	SVM HeaderParse 0.1
AUTHOR AFFIL	y	SVM HeaderParse 0.2
AUTHOR NAME	Tony Lauck	SVM HeaderParse 0.1
AUTHOR AFFIL	z	SVM HeaderParse 0.2
ABSTRACT	Conventional algorithms to implement an Operating System timer module take O(n) time to start or maintain a timer, where n is the number of outstanding timers: this is expensive for large n. This paper shows that by using a circular buffer or timing wheel, it takes O(1) time to start, stop, and maintain timers within the range of the wheel. Two extensions for larger values of the interval are described. In the first, the timer interval is hashed into a slot on the timing wheel. In the second, a hierarchy of timing wheels with different granularities is used to span a greater range of intervals. The performance of these two schemes and various implementation tradeoffs are discussed. We have used one of our schemes to replace the current BSD UNIX callout and timer facilities. Our new implementation can support thousands of outstanding timers without much overhead. Our timer schemes have also been implemented in other operating systems and network protocol packages. 1 Introduction In a ...	user correction - Legacy Corrections
YEAR	1996	user correction - Legacy Corrections
CITATIONS	24 found	ParsCit 1.0