On Sat, 2007-05-19 at 13:33 +1000, Paul Mackerras wrote: > Daniel Walker writes: > > > On Fri, 2007-05-18 at 19:06 +0400, Sergei Shtylyov wrote: > > > Well, the decrementer frequency may change, at least in theory (if > > > the bus > > > clock changes). > > > > Does that happen very often? > > If it did, gettimeofday would start reporting seriously wrong values, > since the timebase and the decrementer count at the same rate, and we > don't have any provision for fixing things up if that rate changed. > Fortunately there are no powerpc platforms where the rate is > variable.
In terms of clocksources, gettimeofday() would have to switch to another clocksource if the decrementer started to act that way .. That's why it is possible to register more than one clocksource, to allow for the switching. The decrementer frequency doesn't change even with cpufreq? Daniel - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
