On Tue, 2008-01-22 at 17:05 +0100, Ingo Molnar wrote: > * S.Çağlar Onur <[EMAIL PROTECTED]> wrote: > > > > My theory is that for whatever reason we get "repeat" IPIs: multiple > > > reschedule IPIs although the other CPU only initiated one. > > > > Ok, please see http://cekirdek.pardus.org.tr/~caglar/dmesg.3rd :) > > hm, the IPI sending and receiving is nicely paired up: > > [ 625.795008] IPI (@smp_reschedule_interrupt) from task swapper:0 on CPU#1: > [ 625.795223] IPI (@native_smp_send_reschedule) from task amarokapp:2882 on > CPU#1: > > amarokapp does wake up threads every 20 microseconds - that could > explain it. It's probably Xorg running on one core, amarokapp on the > other core. That's already 100 reschedules/sec.
That suggests we want an "anti-load-balancing" heuristic when CPU usage is very low. Migrating everything onto one core when we're close to idle will save power and probably reduce latencies. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
