On Thu, Apr 09, 2015 at 09:20:39AM +0200, Ingo Molnar wrote: > if at least one base is active (on my fairly standard system all cpus > have at least one active hrtimer base all the time - and many cpus > have two bases active), then we run hrtimer_get_softirq_time(), which > dirties the cachelines of all 4 clock bases: > > base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim; > base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono; > base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot; > base->clock_base[HRTIMER_BASE_TAI].softirq_time = tai; > > so in practice we not only touch every cacheline in every timer > interrupt, but we _dirty_ them, even the inactive ones. >
Urgh we should really _really_ kill that entire softirq mess. All it needs it hrtimer_start*() returning -ENOTIME when it cannot queue the timer. Of course, all that needs it auditing all hrtimer_start*() callsites, which is a lot of work. -- 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/