Messages in this thread | | | Date | Thu, 24 Sep 2009 18:00:51 +0200 | From | Martin Schwidefsky <> | Subject | Re: [RFC PATCH] timer: provide microaccounting for iowait in addition to idle time |
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On Thu, 24 Sep 2009 13:39:38 +0200 Arjan van de Ven <arjan@infradead.org> wrote:
> @@ -190,19 +195,61 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts) > u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) > { > struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); > + ktime_t now, delta; > > if (!tick_nohz_enabled) > return -1; > > - if (ts->idle_active) > - *last_update_time = ktime_to_us(ts->idle_lastupdate); > - else > - *last_update_time = ktime_to_us(ktime_get()); > + now = ktime_get(); > + if (ts->idle_active) { > + delta = ktime_sub(now, ts->idle_entrytime); > + ts->idle_lastupdate = now; > + ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); > + if (nr_iowait_cpu()>0) > + ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); > + ts->idle_entrytime = now; > + } > + > + if (last_update_time) { > + if (ts->idle_active) > + *last_update_time = ktime_to_us(ts->idle_lastupdate); > + else > + *last_update_time = ktime_to_us(ktime_get()); > + } > > return ktime_to_us(ts->idle_sleeptime); > } > EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
Is the second ktime_get() call really necessary? Why can't "now" be reused?
> +u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time) > +{ > + struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); > + ktime_t now, delta; > + > + if (!tick_nohz_enabled) > + return -1; > + > + now = ktime_get(); > + if (ts->idle_active) { > + delta = ktime_sub(now, ts->idle_entrytime); > + ts->idle_lastupdate = now; > + ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); > + if (nr_iowait_cpu()>0) > + ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); > + ts->idle_entrytime = now; > + } > + > + if (last_update_time) { > + if (ts->idle_active) > + *last_update_time = ktime_to_us(ts->idle_lastupdate); > + else > + *last_update_time = ktime_to_us(ktime_get()); > + } > + > + return ktime_to_us(ts->iowait_sleeptime); > +} > +EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
Same here.
But except for the superfluous ktime_gets I have no objections.
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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