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authorVenkatesh Pallipadi <venki@google.com>2010-10-04 17:03:22 -0700
committerIngo Molnar <mingo@elte.hu>2010-10-18 20:52:27 +0200
commitaa483808516ca5cacfa0e5849691f64fec25828e (patch)
tree38a1d9f1cb1157bd68dc2475447bacbb4b63c64a /kernel/sched.c
parent305e6835e05513406fa12820e40e4a8ecb63743c (diff)
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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 <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1286237003-12406-8-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 9e01b7100ef..bff9ef537df 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"