On Fri, Jan 31, 2014 at 02:15:47PM +0530, Preeti Murthy wrote: > > > > If the driver does its own random mapping that will break the governor > > logic. So yes, the states are ordered, the higher the index is, the more you > > save power and the higher the exit latency is. > > The above point holds true for only the ladder governor which sees the idle > states indexed in the increasing order of target_residency/exit_latency. > > However this is not true as far as I can see in the menu governor. It > acknowledges the dynamic ordering of idle states as can be seen in the > menu_select() function in the menu governor, where the idle state for the > CPU gets chosen. You will notice that, even if it is found that the predicted > idle time of the CPU is smaller than the target residency of an idle state, > the governor continues to search for suitable idle states in the higher > indexed > states although it should have halted if the idle states' were ordered > according > to their target residency.. The same holds for exit_latency. > > Hence I think this patch would make sense only with additional information > like exit_latency or target_residency is present for the scheduler. The idle > state index alone will not be sufficient.
Alternatively, can we enforce sanity on the cpuidle infrastructure to make the index naturally ordered? If not, please explain why :-) -- 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/