Re: boot time, process start time, and NOW time

[James Courtier-Dutton]

Albert Cahalan wrote:
> > > That's userspace, which works fine on a 2.4.xx kernel.
> > > If userspace were to change, it wouldn't work OK for
> > > a 2.4.xx kernel anymore. So consider that cast in stone.
> > >
> > > "now" is the time() function. Using gettimeofday()
> > > would only make sense if I decided to pay the cost
> > > of asking for the time every time I look at a task.

While on the subject of time, is it possible to get a monotonic timer 
with 1ms or better resolution?
We need this for linux multimedia applications, and it is used to sync 
audio and video. Currently we use gettimeofday(). If a movie is playing, 
and the user goes and changes the time, or changes the timezone, we do 
not want that to effect the movie playing. I have not been able to find 
a monotonic 1ms accurate timer in the linux kernel, that is available to 
applications, and has little overhead. Some efficient ioctl or function 
call for uptime to 1ms accuracy would do perfectly.

James
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