On Sat, Jul 19, 2014 at 01:31:25PM -0400, Nicolas Pitre wrote: > On Sat, 19 Jul 2014, Frederic Weisbecker wrote: > > > The timekeeper gets initialized to the value of the CPU where the > > first clockevent device is setup. This works well because the timekeeper > > can be any online CPU in most configs. > > > > Full dynticks has its own requirement though and needs the timekeeper > > to always be 0. And this requirement seem to accomodate pretty well with > > the above described boot timekeeper setting because the first clockevent > > device happens to be initialized, most of the time, on the boot CPU > > (which should be CPU 0). > > This might have been discussed before... but this isn't ARM big.LITTLE > friendly at all. > > Could we accommodate for any arbitrary CPU instead of making CPU 0 > "special" other than its role as the boot CPU please? It doesn't have > to be completely dynamic, but CPU 0 might be a really bad choice for > ongoing periodic duties in some configurations. For example, we might > highly prefer to do this on CPU 4 for power efficiency reasons once it > is online and keep CPU 0 in a deep C-state as much as possible.
This is because CPU0 can be a big core, right? IIRC this is done because a big core as boot cpu, boots faster and some people think boot time is relevant. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/