On Tue, Oct 16, 2012 at 07:03:43PM +0200, Stephen Warren wrote: > On 10/16/2012 02:06 AM, Peter De Schrijver wrote: > >>> Even though we have plan to use coupled cpuidle, I still prefer to go > >>> with the LP2 driver first. Then adding one more patch to support coupled > >>> cpuidle based on LP2 driver. This is good for history. And if there is > >>> any issue, it's more easy to roll back to the stable one. > >> > >> I don't think that implementing it one way and then changing to a > >> different way will benefit history at all. It'll make the history more > >> complicated. What exactly is the problem with just using coupled cpuidle > >> from the start? If we did merge this implementation now, then switch to > >> coupled cpuidle later, when do you think the switch would happen? > > > > Before we consider doing this, I think we should have some idea on how > > frequently we run into the situation where CPU0 is idle but a secondary > > core is not. Depending on that we can then decide how useful coupled cpuidle > > would be for us. > > Would it not be 75% of the time where we have 1 of 4 CPUs active? At > least, that's assuming that all work is evenly distributed amongst CPUs, > and hence it's random which CPU is the last to go idle, but perhaps > that's not the case if CPU0 is somehow special workload-wise? > Depends, at least it used to be possible to tune the scheduler to prefer CPU0 if the workload can run on a single CPU. Cheers, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
