On Tue, 19 Feb 2013, Daniel Lezcano wrote: > I am working on identifying the different wakeup sources from the > interrupts and I have a question regarding the timer broadcast. > > The broadcast timer is setup to the next event and that will wake up any > idle cpu belonging to the "broadcast cpumask", right ? > > The cpu which has been woken up will look for each cpu the next-event > and send an IPI to wake it up. > > Although, it is possible the sender of this IPI may not be concerned by > the timer expiration and has been woken up just for sending the IPI, right ?
Correct. > If this is correct, is it possible to setup the timer irq affinity to a > cpu which will be concerned by the timer expiration ? so we prevent an > unnecessary wake up for a cpu. It is possible, but we never implemented it. If we go there, we want to make that conditional on a property flag, because some interrupt controllers especially on x86 only allow to move the affinity from interrupt context, which is pointless. Thanks, tglx -- 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/