On Thu, 8 Oct 2009 16:55:36 +0200 Frans Pop <elendil@xxxxxxxxx> wrote: > > It turns out that on x86, these two 'opportunistic' timers only > > get checked when another "real" timer happens. > > These opportunistic timers have the objective to save power by > > hitchhiking on other wakeups, as to avoid CPU wakeups by themselves > > as much as possible. > > This patch makes quite a difference for me. iwlagn and phy0 now > consistently show at ~10 ms or lower.\ most excellent > I do still get occasional high latencies, but those are for things > like "[rpc_wait_bit_killable]" or "Writing a page to disk", where I > guess you'd expect them. Those high latencies are mostly only listed > for "Global" and don't translate to individual processes. and they're very different types of latencies, caused by disk and such. > The ~10 ms I still get for iwlagn and phy0 (and sometimes higher (~30 > ms) for others like Xorg and artsd) is still "Scheduler: waiting for > cpu'. If it is actually due to (un)interuptable sleep, isn't that a > misleading label? I directly associated that with scheduler latency. it's actually the time between wakeup and running, as measured by scheduler statistics -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
