Efficient Timer Algorithm

Question

What is the best algorithm to implement a simple timer library. The library should allow the following:

1. Timers to be started
2. Timers to be stopped

Answer 1

On POSIX-ish systems, you can use the timer_create/timer_settime family of functions to provide a lot of this "for free."

Answer 2

Timers are typically best implemented in an operating system kernel, at the assembly/C level, making use of platform-specific features like APIC timers wherever possible.

You might like to look at http://lwn.net/Articles/167897/ for details on the Linux implementation, and dig through the Linux source code to see working implementations.

Answer 3

Best algorithm I have seen for timers is a timer wheel found in the research paper Hashed and Hierarchical Timing Wheels: Data Structures for the Efficient Implementation of a Timer Facility

I know in Java there is an implementation with Netty, JBoss and I am sure elsewhere too that you can use, if you are writing in Java.