id	summary	reporter	owner	description	type	status	priority	milestone	component	resolution	keywords	cc	branch	branch_author	launchpad_bug
5552	accurate periodic calls	zoranbosnjak		"Twisted reactor uses python's time.time() to handle time intervals and periodic calls.

On posix (on python 2.7), this provides incorrect behaviour if the system time changes during program execution. At this situation, all pending time calculations are wrong by this time jump (which can be huge). So the program would yield completely wrong timing responses or might even stall.

The reactor shall (by default) not depend on system time, but instead on some form of monotonic time.

To workaround the problem, an application can do something like this:
---
from twisted.internet import reactor
from monotonic_time import monotonic_time
reactor.seconds = monotonic_time
---

Example monotonic_time implementation is attached for posix platform. Not sure about other platforms.

I recommend to include monotonic time as default behaviour of the reactor.
"	defect	closed	normal		core	duplicate	reactor, monotonic time, looping, periodic