Re: gettimeofday() goes backwards on FreeBSD 4.9

On Fri, 28 Nov 2003, Tom Lane wrote:

> "Nigel J. Andrews" <nandrews@investsystems.co.uk> writes:
> > On an Intel Linux 2.4.18 I get them quite often, 25 in 1'45", but they
> > are all just a microsecond.
> 
> What do you mean by "just a microsecond"?

I mean it's always a "out of order tv_usec..." line and the difference is
1us. That is a.out gives:

out of order tv_usec: 1070065862 374978, prev 1070065862 374979
out of order tv_usec: 1070065867 814300, prev 1070065867 814301
out of order tv_usec: 1070065868 794176, prev 1070065868 794177
out of order tv_usec: 1070065871 553831, prev 1070065871 553832

etc.


> 
> Attached is a tightened-up test program that will only complain if the
> value of gettimeofday goes backward (at all) or forward by more than
> 10 seconds (adjustable as MAX_SKIP).  This should be suitable to run on
> moderately loaded machines where the test program might occasionally not
> get dispatched for a few seconds.

I don't think that would show any for me. I've only got two skips showing from
a longer run on my FreeBSD 3.3 and those differ in the seconds counter by only
2. Time between the occurances is about 1100s.


--
Nigel