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Message-Id: <1371761141-25386-4-git-send-email-fweisbec@gmail.com>
Date: Thu, 20 Jun 2013 22:45:40 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...nel.org>,
Li Zhong <zhong@...ux.vnet.ibm.com>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Peter Zijlstra <peterz@...radead.org>,
Steven Rostedt <rostedt@...dmis.org>,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...en8.de>, Alex Shi <alex.shi@...el.com>,
Paul Turner <pjt@...gle.com>, Mike Galbraith <efault@....de>,
Vincent Guittot <vincent.guittot@...aro.org>
Subject: [RFC PATCH 3/4] sched: Conditionally build decaying cpu load stats
Now that the decaying cpu load stat indexes used by LB_BIAS
are ignored in full dynticks mode, let's conditionally build
that code to optimize the off case.
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Li Zhong <zhong@...ux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Alex Shi <alex.shi@...el.com>
Cc: Paul Turner <pjt@...gle.com>
Cc: Mike Galbraith <efault@....de>
Cc: Vincent Guittot <vincent.guittot@...aro.org>
---
kernel/sched/proc.c | 45 ++++++++++++++++++++++++++++-----------------
kernel/sched/sched.h | 4 ++++
2 files changed, 32 insertions(+), 17 deletions(-)
diff --git a/kernel/sched/proc.c b/kernel/sched/proc.c
index 030528a..34920e4 100644
--- a/kernel/sched/proc.c
+++ b/kernel/sched/proc.c
@@ -394,6 +394,7 @@ static void calc_load_account_active(struct rq *this_rq)
this_rq->calc_load_update += LOAD_FREQ;
}
+#ifdef CONFIG_NO_HZ_IDLE
/*
* End of global load-average stuff
*/
@@ -465,26 +466,13 @@ decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
return load;
}
-/*
- * Update rq->cpu_load[] statistics. This function is usually called every
- * scheduler tick (TICK_NSEC). With tickless idle this will not be called
- * every tick. We fix it up based on jiffies.
- */
-static void __update_cpu_load(struct rq *this_rq, unsigned long this_load)
+static void update_cpu_load_decayed(struct rq *this_rq, unsigned long this_load,
+ unsigned long pending_updates)
{
- unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
- unsigned long pending_updates;
int i, scale;
+ unsigned long old_load, new_load;
- pending_updates = curr_jiffies - this_rq->last_load_update_tick;
- this_rq->last_load_update_tick = curr_jiffies;
- this_rq->nr_load_updates++;
-
- /* Update our load: */
- this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
- unsigned long old_load, new_load;
-
/* scale is effectively 1 << i now, and >> i divides by scale */
old_load = this_rq->cpu_load[i];
@@ -500,6 +488,30 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load)
this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
}
+}
+#else /* CONFIG_NO_HZ_IDLE */
+static inline void update_cpu_load_decayed(struct rq *this_rq, unsigned long this_load,
+ unsigned long pending_updates)
+{ }
+#endif
+
+/*
+ * Update rq->cpu_load[] statistics. This function is usually called every
+ * scheduler tick (TICK_NSEC). With tickless idle this will not be called
+ * every tick. We fix it up based on jiffies.
+ */
+static void __update_cpu_load(struct rq *this_rq, unsigned long this_load)
+{
+ unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
+ unsigned long pending_updates;
+
+ pending_updates = curr_jiffies - this_rq->last_load_update_tick;
+ this_rq->last_load_update_tick = curr_jiffies;
+ this_rq->nr_load_updates++;
+
+ /* Update our load: */
+ this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
+ update_cpu_load_decayed(this_rq, this_load, pending_updates);
sched_avg_update(this_rq);
}
@@ -561,6 +573,5 @@ void update_cpu_load_nohz(void)
void update_cpu_load_active(struct rq *this_rq)
{
__update_cpu_load(this_rq, this_rq->load.weight);
-
calc_load_account_active(this_rq);
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 029601a..ffa241df 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -410,7 +410,11 @@ struct rq {
* remote CPUs use both these fields when doing load calculation.
*/
unsigned int nr_running;
+#ifdef CONFIG_NO_HZ_IDLE
#define CPU_LOAD_IDX_MAX 5
+#else
+ #define CPU_LOAD_IDX_MAX 1
+#endif
unsigned long cpu_load[CPU_LOAD_IDX_MAX];
unsigned long last_load_update_tick;
#ifdef CONFIG_NO_HZ_COMMON
--
1.7.5.4
--
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