From aa483808516ca5cacfa0e5849691f64fec25828e Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Mon, 4 Oct 2010 17:03:22 -0700 Subject: sched: Remove irq time from available CPU power The idea was suggested by Peter Zijlstra here: http://marc.info/?l=linux-kernel&m=127476934517534&w=2 irq time is technically not available to the tasks running on the CPU. This patch removes irq time from CPU power piggybacking on sched_rt_avg_update(). Tested this by keeping CPU X busy with a network intensive task having 75% oa a single CPU irq processing (hard+soft) on a 4-way system. And start seven cycle soakers on the system. Without this change, there will be two tasks on each CPU. With this change, there is a single task on irq busy CPU X and remaining 7 tasks are spread around among other 3 CPUs. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Peter Zijlstra LKML-Reference: <1286237003-12406-8-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 9e01b7100ef6..bff9ef537df0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -519,6 +519,10 @@ struct rq { u64 avg_idle; #endif +#ifdef CONFIG_IRQ_TIME_ACCOUNTING + u64 prev_irq_time; +#endif + /* calc_load related fields */ unsigned long calc_load_update; long calc_load_active; @@ -643,6 +647,7 @@ static inline struct task_group *task_group(struct task_struct *p) #endif /* CONFIG_CGROUP_SCHED */ static u64 irq_time_cpu(int cpu); +static void sched_irq_time_avg_update(struct rq *rq, u64 irq_time); inline void update_rq_clock(struct rq *rq) { @@ -654,6 +659,8 @@ inline void update_rq_clock(struct rq *rq) irq_time = irq_time_cpu(cpu); if (rq->clock - irq_time > rq->clock_task) rq->clock_task = rq->clock - irq_time; + + sched_irq_time_avg_update(rq, irq_time); } } @@ -1985,6 +1992,15 @@ void account_system_vtime(struct task_struct *curr) local_irq_restore(flags); } +static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) +{ + if (sched_clock_irqtime && sched_feat(NONIRQ_POWER)) { + u64 delta_irq = curr_irq_time - rq->prev_irq_time; + rq->prev_irq_time = curr_irq_time; + sched_rt_avg_update(rq, delta_irq); + } +} + #else static u64 irq_time_cpu(int cpu) @@ -1992,6 +2008,8 @@ static u64 irq_time_cpu(int cpu) return 0; } +static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) { } + #endif #include "sched_idletask.c" -- cgit v1.2.3-59-g8ed1b