On Thu, Feb 18, 2016 at 12:09 AM, Rafael J. Wysocki <[email protected]> wrote: > On Tue, Feb 16, 2016 at 5:44 PM, Nicolas Pitre <[email protected]> > wrote: >> On Tue, 16 Feb 2016, Daniel Lezcano wrote: >> >>> Many IRQs are quiet most of the time, or they tend to come in bursts of >>> fairly equal time intervals within each burst. It is therefore possible >>> to detect those IRQs with stable intervals and guestimate when the next >>> IRQ event is most likely to happen. >>> >>> Examples of such IRQs may include audio related IRQs where the FIFO size >>> and/or DMA descriptor size with the sample rate create stable intervals, >>> block devices during large data transfers, etc. Even network streaming >>> of multimedia content creates patterns of periodic network interface IRQs >>> in some cases. >>> >>> This patch adds code to compute the mean interval and variance for each IRQ >>> over a window of time intervals between IRQ events. Those statistics can >>> be used to assist cpuidle in selecting the most appropriate sleep state >>> by predicting the most likely time for the next interrupt. >>> >>> Signed-off-by: Daniel Lezcano <[email protected]> >> >> The math in next_irq_event() is correct even though I think it could be >> done more simply. But that can be optimized at a later time. >> >> Reviewed-by: Nicolas Pitre <[email protected]> > > Well, I'm likely overlooking something, but how is this going to be > hooked up to the code in idle.c?
My somewhat educated guess is that sched_idle() in your patch is intended to replace cpuidle_idle_call(), right? If so, why do you want to replace it? And assuming that you have a good enough reason to do that, you need to ensure that suspend-to-idle will work anyway. Thanks, Rafael
