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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