Re: time warps, I despair

Ingo Molnar (
Thu, 31 Oct 1996 10:41:49 +0100 (MET)

On Thu, 31 Oct 1996, Ulrich Windl wrote:

> So what's the effect? From time to time the clock offset jumps for
> some amount always less or equal to what's worth one tick (i.e.
> offset jumps around from -5ms to 5ms when synchronized). To thos who
> might get an idea when they see the pattern, I put two files on a FTP
> server (

i think my previous post wasnt exact enough:

... >anomalies< might happen in 2.0. Note the comment in time.c:

* Fast hack to avoid time warps if calling do_gettimeofday() from an
* interrupt handler. A better solution will be done in 2.1

this means an ugly detection is done in gettimeofday that prevents time
warps (but not anomalies).

- from user space no anomalies and no time warps should happen, in 2.0.
- from an interrupt handler, anomalies might happen, to be fixed in 2.1

-- mingo