Re: [PATCHSET] Announce: High-res timers, tickless/dyntick and dynamic HZ -V4

Pavel Machek
2006-06-30T21:09:34Z

Hi!

> > > > I briefly tested -dyntick5 on my thinkpad, and it seems to work
> > > > okay... but timer still seems to tick at 250Hz.
> > >
> > > > ...am I doing something wrong?
> > >
> > > can you send me the bootlog and your .config file please ?
> >
> > ...attached. (I do not have to enable anything in sysfs/commandline to
> > enable noidlehz, right?).
>
> Right.
>
> You trapped into the no apic on SMP trap. I did not come around to fix
> that yet. What happens that you don't have lapic on the commandline and
> BIOS has lapic disabled. Therefor Linux switches to IPI broadcasting if
> the PIT interrupt, which does not work with idle_hz and highres timer as
> those are per cpu. I will fix that for SMP kernels which bring up only
> one CPU.
>
> You can work around that for now by either using an UP kernel or
> enabling local APIC, which is recommended anyway because the APIC timer
> is faster to access and has longer max time than PIT.

Thanks, it works okay with UP kernel.
Pavel
--
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