Re: /proc or ps tools bug? 2.6.3, time is off

[George Anzinger]

john stultz wrote:
> On Thu, 2004-05-06 at 17:33, George Anzinger wrote:
>
> > john stultz wrote:
> >
> > > Roughly, I'd like to see the time code for all arches in 2.7 to look
> > > like:
> > >
> > > u64 system_time 	/* NTP adjusted nanosecs since boot */
> > > u64 wall_time_offset	/* offset to system_time for time of day */
> > > u64 offset_base		/* last read raw hw value */
> >
> > Hm.  In 2.6 we use an NTP adjusted wall time and a wall_to_monotonic offset.  I 
> > don't really see the advantage here.  Does this change buy us something?
> > For what its worth, I introduced the wall_to_monotonic offset just because it 
> > was easier to do (and understand, I think) in the current kernel.
>
>
> Well, in my opinion it seems much cleaner. Right now any time we adjust
> xtime, we have to remember to adjust wall_to_monotonic. I believe we've
> had issues where a change was made to just one and not the other. 
>
> This is easier and has simpler rules. system_time always increments and
> is only modified by the periodic time_interrupt_hook(). Then
> wall_time_offset is only changes by do_settimeofday(). In fact, I hope
> to make these values static to the time code, so that all in-kernel
> users must go through the monotonic_clock() and do_gettimeofday()
> interfaces. 

All that is fine for the kernel coder and such, but the fact remains that 
gettimeofday() is the BIG user and I keep seeing folks trying to make it faster. 
 Also xtime.tv_sec is used a LOT in the kernel under the name: get_seconds().
~>
--
George Anzinger   george@xxxxxxxxxx
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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