Firefox performs a number of tasks (like checking for an application update or flushing Places updates to disk) that don't necessarily need to be done immediately and could be delayed until the CPU and/or network is idle. In some cases, delaying these tasks to an idle moment could improve the responsiveness of the application. We should implement a service that queues such tasks and executes them at the appropriate time. The service should distinguish between tasks to be performed during idle CPU and those waiting for idle network (or both). And tasks should be able to set a upper bound on how long they can be delayed.

on a related note, there is a bug about not prompting on update when the user is busy, as the software update dialog can grab your keystroke. (I'll find the bug #) i think tbird could benefit from this as well, especially to avoid doing certain tasks when the user is busy typing away in the compose window.

myk, please see bug #349251 comment #5 and comment #6

Seth: good point. Perhaps there's a third category of tasks that should wait until the user isn't (or doesn't appear to be) using input devices.

I have created an extension that periodically pings a remote server using XHR looking for new information. In the case where the user is not using the application I would like to not ping the server (or perhaps reduce the frequency) - reducing unnecessary load on the remote server.

note: benjamin points out we already have nsIIdleService on the trunk, see bug #343416

This is really not what you want, afaict. nsIIdleService is about user idle time, and has nothing to do with CPU or network idle time, as the idl says pretty clearly, as far as I'm concerned.

Ugh, I need to read more comments before commenting. That said, the summary isn't quite accurate anymore, as far as I can tell. Sorry!

Right, here's a new summary about extending the idle service, which I didn't know about before, to support CPU/network idle notifications in addition to the current user activity notifications.