On Wed, 2007-05-16 at 12:12 +0200, Robert Schwebel wrote: > > > Once again. On this piece of hardware there is no other useful timer as > > > the > > > PIT. > > > > Cyclictest tell me this: > > > > "WARNING: High resolution timers not available" > > > > also if i add "clocksource=pit" in the kernel command line! :-( > > Looks like it didn't switch to highres mode. You can check this by > looking into /proc/timer_list.
It can _NOT_ switch into highres mode on a machine, where the only clock source is the PIT. Highres / dyntick mode requires a reliable continuous counting clock source to keep track of time. PIT is not continuous. We can use PIT as clock source only when PIT is in periodic mode, but it is slow and unreliable. If we would switch to highres/dyntick with PIT we would lose track of time completely, because we would try to read the time from the device which we use to program the next event interrupt. There is no way to solve this on systems, which have only a PIT. tglx - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html