Maintaining Timers
That was, is, and shall be: Time’s wheel runs back or stops.
— ROBERT BROWNING
A timer module in a system is analogous to a secretary who keeps track of all the appointments of a busy executive. The executive tells the secretary to schedule appointments and sometimes to cancel appointments before they occur. It is the secretary’s job to interrupt the executive with a warning just before the scheduled time of an appointment. Many secretaries actually do this using a so-called tickler file, which is a moving window over the next N days. When the day’s appointments are done, the tickler file is rolled to bypass the current day. We will find a strong analogy between a tickler file and a timing wheel, the main data structure ...
Get Network Algorithmics now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
