[patch 2/2] sched: Fix and rate-limit newidle
Mike Galbraith
sched: Fix and rate-limit newidle
Commit 1b9508f, "Rate-limit newidle" has been confirmed to fix the netperf
UDP loopback regression reported by Alex Shi. This is a replacement, moved
to a more out of the way spot, and with a fix to ensure that balancing
doesn't try to balance runqueues which haven't gone online yet, which can
mess up CPU enumeration during boot.
Signed-off-by: Mike Galbraith <efa...@gmx.de>
Cc: Peter Zijlstra <a.p.zi...@chello.nl>
Reported-by: Alex Shi <alex...@intel.com>
Reported-by: Zhang, Yanmin <yanmin...@linux.intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mi...@elte.hu>
---
kernel/sched.c | 28 +++++++++++++++++++++++++---
kernel/sched_debug.c | 2 ++
2 files changed, 27 insertions(+), 3 deletions(-)
Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -589,6 +589,8 @@ struct rq {
u64 rt_avg;
u64 age_stamp;
+ u64 idle_stamp;
+ u64 avg_idle;
#endif
/* calc_load related fields */
@@ -2437,6 +2439,17 @@ out_running:
#ifdef CONFIG_SMP
if (p->sched_class->task_wake_up)
p->sched_class->task_wake_up(rq, p);
+
+ if (unlikely(rq->idle_stamp)) {
+ u64 delta = rq->clock - rq->idle_stamp;
+ u64 max = 2*sysctl_sched_migration_cost;
+
+ if (delta > max)
+ rq->avg_idle = max;
+ else
+ update_avg(&rq->avg_idle, delta);
+ rq->idle_stamp = 0;
+ }
#endif
out:
task_rq_unlock(rq, &flags);
@@ -4114,7 +4127,7 @@ static int load_balance(int this_cpu, st
unsigned long flags;
struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
- cpumask_setall(cpus);
+ cpumask_copy(cpus, cpu_online_mask);
/*
* When power savings policy is enabled for the parent domain, idle
@@ -4277,7 +4290,7 @@ load_balance_newidle(int this_cpu, struc
int all_pinned = 0;
struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
- cpumask_setall(cpus);
+ cpumask_copy(cpus, cpu_online_mask);
/*
* When power savings policy is enabled for the parent domain, idle
@@ -4417,6 +4430,11 @@ static void idle_balance(int this_cpu, s
int pulled_task = 0;
unsigned long next_balance = jiffies + HZ;
+ this_rq->idle_stamp = this_rq->clock;
+
+ if (this_rq->avg_idle < sysctl_sched_migration_cost)
+ return;
+
for_each_domain(this_cpu, sd) {
unsigned long interval;
@@ -4431,8 +4449,10 @@ static void idle_balance(int this_cpu, s
interval = msecs_to_jiffies(sd->balance_interval);
if (time_after(next_balance, sd->last_balance + interval))
next_balance = sd->last_balance + interval;
- if (pulled_task)
+ if (pulled_task) {
+ this_rq->idle_stamp = 0;
break;
+ }
}
if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
/*
@@ -9535,6 +9555,8 @@ void __init sched_init(void)
rq->cpu = i;
rq->online = 0;
rq->migration_thread = NULL;
+ rq->idle_stamp = 0;
+ rq->avg_idle = 2*sysctl_sched_migration_cost;
INIT_LIST_HEAD(&rq->migration_queue);
rq_attach_root(rq, &def_root_domain);
#endif
Index: linux-2.6/kernel/sched_debug.c
===================================================================
--- linux-2.6.orig/kernel/sched_debug.c
+++ linux-2.6/kernel/sched_debug.c
@@ -285,12 +285,14 @@ static void print_cpu(struct seq_file *m
#ifdef CONFIG_SCHEDSTATS
#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
+#define P64(n) SEQ_printf(m, " .%-30s: %Ld\n", #n, rq->n);
P(yld_count);
P(sched_switch);
P(sched_count);
P(sched_goidle);
+ P64(avg_idle);
P(ttwu_count);
P(ttwu_local);
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Gitweb: http://git.kernel.org/tip/eae0c9dfb534cb3449888b9601228efa6480fdb5
Author: Mike Galbraith <efa...@gmx.de>
AuthorDate: Tue, 10 Nov 2009 03:50:02 +0100
Committer: Ingo Molnar <mi...@elte.hu>
CommitDate: Tue, 10 Nov 2009 04:25:58 +0100
sched: Fix and clean up rate-limit newidle code
Commit 1b9508f, "Rate-limit newidle" has been confirmed to fix
the netperf UDP loopback regression reported by Alex Shi.
This is a cleanup and a fix:
- moved to a more out of the way spot
- fix to ensure that balancing doesn't try to balance
runqueues which haven't gone online yet, which can
mess up CPU enumeration during boot.
Reported-by: Alex Shi <alex...@intel.com>
Reported-by: Zhang, Yanmin <yanmin...@linux.intel.com>
Signed-off-by: Mike Galbraith <efa...@gmx.de>
Acked-by: Peter Zijlstra <a.p.zi...@chello.nl>
Cc: <sta...@kernel.org> # .32.x: a1f84a3: sched: Check for an idle shared cache
Cc: <sta...@kernel.org> # .32.x: 1b9508f: sched: Rate-limit newidle
Cc: <sta...@kernel.org> # .32.x: fd21073: sched: Fix affinity logic
Cc: <sta...@kernel.org> # .32.x
LKML-Reference: <1257821402.5...@marge.simson.net>
Signed-off-by: Ingo Molnar <mi...@elte.hu>
---
kernel/sched.c | 28 +++++++++++++++-------------
1 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 23e3535..ad37776 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2354,17 +2354,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
if (rq != orig_rq)
update_rq_clock(rq);
- if (rq->idle_stamp) {
- u64 delta = rq->clock - rq->idle_stamp;
- u64 max = 2*sysctl_sched_migration_cost;
-
- if (delta > max)
- rq->avg_idle = max;
- else
- update_avg(&rq->avg_idle, delta);
- rq->idle_stamp = 0;
- }
-
WARN_ON(p->state != TASK_WAKING);
cpu = task_cpu(p);
@@ -2421,6 +2410,17 @@ out_running:
#ifdef CONFIG_SMP
if (p->sched_class->task_wake_up)
p->sched_class->task_wake_up(rq, p);
+
+ if (unlikely(rq->idle_stamp)) {
+ u64 delta = rq->clock - rq->idle_stamp;
+ u64 max = 2*sysctl_sched_migration_cost;
+
+ if (delta > max)
+ rq->avg_idle = max;
+ else
+ update_avg(&rq->avg_idle, delta);
+ rq->idle_stamp = 0;
+ }
#endif
out:
task_rq_unlock(rq, &flags);
@@ -4098,7 +4098,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
unsigned long flags;
struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
- cpumask_setall(cpus);
+ cpumask_copy(cpus, cpu_online_mask);
/*
* When power savings policy is enabled for the parent domain, idle
@@ -4261,7 +4261,7 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
int all_pinned = 0;
struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
- cpumask_setall(cpus);
+ cpumask_copy(cpus, cpu_online_mask);
/*
* When power savings policy is enabled for the parent domain, idle
@@ -9522,6 +9522,8 @@ void __init sched_init(void)
rq->cpu = i;
rq->online = 0;
rq->migration_thread = NULL;
+ rq->idle_stamp = 0;
+ rq->avg_idle = 2*sysctl_sched_migration_cost;
INIT_LIST_HEAD(&rq->migration_queue);
rq_attach_root(rq, &def_root_domain);
#endif