There are times when you want to recreate a network test that would typically take a while to complete. In addition, when you run the tests, you want the results to be consistent in different runs.
In this talk, Johannes Berg and Richard Weinberger describe their solution to this requirement. They introduce a mechanism to do "time travel" in User Mode Linux(UML) with a virtual clock.
The time travel mode allows for reproducible testing at significantly faster test execution times; as an example, on a relatively slow laptop: two simulated machines in such a setup can simulate 61 pings, at a default 1 second interval, in about 1.6 seconds real time (as opposed to 61 seconds).
More info: https://netdevconf.info/0x14/session.html?talk-time-travel-linux-network-sim...
Reminder, registration is now open and early bird is still in effect. https://netdevconf.info/0x14/registration.html
cheers, jamal