[lug] High resolution timers

[Jeffrey Siegal]

D. Stimits wrote:
> average system. I gettimeofday() actually useful as a microsecond 
> resolution clock on non-RT x86 linux?

In short, yes.

> Even the earlier mentioned URL 
> talks about how the scheduler itself can cause a 10 ms error simply by 
> scheduling something else temporarily.

Of course it can.  You can't expect real time behavior with a non-real 
time scheduler.  That's an issue of the scheduler, not gettimeofday.  If 
you use SCHED_FIFO or SCHED_RR, you won't have to be converned deal with 
the scheduler.  There are still other uncontrolled interruptions that 
can occur on a non-RT operating system, but again, that's an issue of 
the OS, not gettimeofday.  You would have exactly the same problems with 
a program running on such an OS reading a hardware timer.