Messages in this thread | | | Date | Mon, 10 Nov 2014 16:15:50 +0100 | From | Daniel Lezcano <> | Subject | Re: [PATCH V3 3/6] sched: idle: Get the next timer event and pass it the cpuidle framework |
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On 11/10/2014 01:43 PM, Peter Zijlstra wrote: > On Fri, Nov 07, 2014 at 03:31:24PM +0100, Daniel Lezcano wrote: >> static void cpu_idle_loop(void) >> { >> - unsigned int latency_req; >> + unsigned int latency_req, next_timer_event; >> >> while (1) { >> /* >> @@ -221,6 +222,9 @@ static void cpu_idle_loop(void) >> >> latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); >> >> + next_timer_event = >> + ktime_to_us(tick_nohz_get_sleep_length()); >> + >> /* >> * In poll mode we reenable interrupts and spin. >> * >> @@ -238,7 +242,8 @@ static void cpu_idle_loop(void) >> tick_check_broadcast_expired()) >> cpu_idle_poll(); >> else >> - cpuidle_idle_call(latency_req); >> + cpuidle_idle_call(latency_req, >> + next_timer_event); >> >> arch_cpu_idle_exit(); >> } > > Why do we want to query the next timer in the poll case? Afaict the > other patches don't make use of this either.
Well, the direction I am taking when writing those cleanups is to have something like:
"I will sleep X usec, I have Y usec latency constraints". Grouping the latency req and the next timer allows to stick to the next changes.
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