[lug] High resolution timers

[D. Stimits]

Ed Hill wrote:

> On Fri, 2003-02-21 at 10:55, Steve Sullivan wrote:
>
> >Hi,
> >I'm interested in running a high resolution timer (1 microsecond or 
> better)
> >with standard redhat 8 or suse 8.1, not with a RT linux system.
> >Has anyone done this?
> >What hardware timer would you recommend?
> >What software did you need?
>
>
>
> I've needed microsecond timing (NOT sub-micro) for an oddball device
> driver and was satisfied with gettimeofday().  It can easily provide 1us
> resolution without any special hardware (or RT kernel extensions) on
> most modern machines:


I doubt that any non-RT extension will get you better than 10 milli 
seconds, even if the code resolves to micro seconds. A question that 
needs to be asked is not just whether it must resolve a micro second, 
but whether it is allowed to have an error of +/- 50 ms (with a 100 Hz 
IRQ rate) on that 1 micro second tick.

D. Stimits, stimits AT attbi DOT com