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sched: fix sched_domain aggregation

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Keeping the aggregate on the first cpu of the sched domain has two problems:
 - it could collide between different sched domains on different cpus
 - it could slow things down because of the remote accesses

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2008-06-27 13:41:18 +02:00 committed by Ingo Molnar
parent 32df2ee86a
commit b6a86c746f
3 changed files with 60 additions and 66 deletions
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1
include/linux/sched.h
View File

@ -765,7 +765,6 @@ struct sched_domain {
struct sched_domain *child; /* bottom domain must be null terminated */
struct sched_group *groups; /* the balancing groups of the domain */
cpumask_t span; /* span of all CPUs in this domain */
int first_cpu; /* cache of the first cpu in this domain */
unsigned long min_interval; /* Minimum balance interval ms */
unsigned long max_interval; /* Maximum balance interval ms */
unsigned int busy_factor; /* less balancing by factor if busy */

113
kernel/sched.c
View File

@ -1480,12 +1480,12 @@ static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
*/
static inline struct aggregate_struct *
aggregate(struct task_group *tg, struct sched_domain *sd)
aggregate(struct task_group *tg, int cpu)
{
return &tg->cfs_rq[sd->first_cpu]->aggregate;
return &tg->cfs_rq[cpu]->aggregate;
}
typedef void (*aggregate_func)(struct task_group *, struct sched_domain *);
typedef void (*aggregate_func)(struct task_group *, int, struct sched_domain *);
/*
* Iterate the full tree, calling @down when first entering a node and @up when
@ -1493,14 +1493,14 @@ typedef void (*aggregate_func)(struct task_group *, struct sched_domain *);
*/
static
void aggregate_walk_tree(aggregate_func down, aggregate_func up,
struct sched_domain *sd)
int cpu, struct sched_domain *sd)
{
struct task_group *parent, *child;
rcu_read_lock();
parent = &root_task_group;
down:
(*down)(parent, sd);
(*down)(parent, cpu, sd);
list_for_each_entry_rcu(child, &parent->children, siblings) {
parent = child;
goto down;
@ -1508,7 +1508,7 @@ down:
up:
continue;
}
(*up)(parent, sd);
(*up)(parent, cpu, sd);
child = parent;
parent = parent->parent;
@ -1520,8 +1520,8 @@ up:
/*
* Calculate the aggregate runqueue weight.
*/
static
void aggregate_group_weight(struct task_group *tg, struct sched_domain *sd)
static void
aggregate_group_weight(struct task_group *tg, int cpu, struct sched_domain *sd)
{
unsigned long rq_weight = 0;
unsigned long task_weight = 0;
@ -1532,15 +1532,15 @@ void aggregate_group_weight(struct task_group *tg, struct sched_domain *sd)
task_weight += tg->cfs_rq[i]->task_weight;
}
aggregate(tg, sd)->rq_weight = rq_weight;
aggregate(tg, sd)->task_weight = task_weight;
aggregate(tg, cpu)->rq_weight = rq_weight;
aggregate(tg, cpu)->task_weight = task_weight;
}
/*
* Compute the weight of this group on the given cpus.
*/
static
void aggregate_group_shares(struct task_group *tg, struct sched_domain *sd)
static void
aggregate_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd)
{
unsigned long shares = 0;
int i;
@ -1548,18 +1548,18 @@ void aggregate_group_shares(struct task_group *tg, struct sched_domain *sd)
for_each_cpu_mask(i, sd->span)
shares += tg->cfs_rq[i]->shares;
if ((!shares && aggregate(tg, sd)->rq_weight) || shares > tg->shares)
if ((!shares && aggregate(tg, cpu)->rq_weight) || shares > tg->shares)
shares = tg->shares;
aggregate(tg, sd)->shares = shares;
aggregate(tg, cpu)->shares = shares;
}
/*
* Compute the load fraction assigned to this group, relies on the aggregate
* weight and this group's parent's load, i.e. top-down.
*/
static
void aggregate_group_load(struct task_group *tg, struct sched_domain *sd)
static void
aggregate_group_load(struct task_group *tg, int cpu, struct sched_domain *sd)
{
unsigned long load;
@ -1571,17 +1571,17 @@ void aggregate_group_load(struct task_group *tg, struct sched_domain *sd)
load += cpu_rq(i)->load.weight;
} else {
load = aggregate(tg->parent, sd)->load;
load = aggregate(tg->parent, cpu)->load;
/*
* shares is our weight in the parent's rq so
* shares/parent->rq_weight gives our fraction of the load
*/
load *= aggregate(tg, sd)->shares;
load /= aggregate(tg->parent, sd)->rq_weight + 1;
load *= aggregate(tg, cpu)->shares;
load /= aggregate(tg->parent, cpu)->rq_weight + 1;
}
aggregate(tg, sd)->load = load;
aggregate(tg, cpu)->load = load;
}
static void __set_se_shares(struct sched_entity *se, unsigned long shares);
@ -1590,8 +1590,8 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares);
* Calculate and set the cpu's group shares.
*/
static void
__update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd,
int tcpu)
__update_group_shares_cpu(struct task_group *tg, int cpu,
struct sched_domain *sd, int tcpu)
{
int boost = 0;
unsigned long shares;
@ -1618,8 +1618,8 @@ __update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd,
* \Sum rq_weight
*
*/
shares = aggregate(tg, sd)->shares * rq_weight;
shares /= aggregate(tg, sd)->rq_weight + 1;
shares = aggregate(tg, cpu)->shares * rq_weight;
shares /= aggregate(tg, cpu)->rq_weight + 1;
/*
* record the actual number of shares, not the boosted amount.
@ -1639,15 +1639,15 @@ __update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd,
* task went to.
*/
static void
__move_group_shares(struct task_group *tg, struct sched_domain *sd,
__move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd,
int scpu, int dcpu)
{
unsigned long shares;
shares = tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares;
__update_group_shares_cpu(tg, sd, scpu);
__update_group_shares_cpu(tg, sd, dcpu);
__update_group_shares_cpu(tg, cpu, sd, scpu);
__update_group_shares_cpu(tg, cpu, sd, dcpu);
/*
* ensure we never loose shares due to rounding errors in the
@ -1663,19 +1663,19 @@ __move_group_shares(struct task_group *tg, struct sched_domain *sd,
* we need to walk up the tree and change all shares until we hit the root.
*/
static void
move_group_shares(struct task_group *tg, struct sched_domain *sd,
move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd,
int scpu, int dcpu)
{
while (tg) {
__move_group_shares(tg, sd, scpu, dcpu);
__move_group_shares(tg, cpu, sd, scpu, dcpu);
tg = tg->parent;
}
}
static
void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd)
static void
aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *sd)
{
unsigned long shares = aggregate(tg, sd)->shares;
unsigned long shares = aggregate(tg, cpu)->shares;
int i;
for_each_cpu_mask(i, sd->span) {
@ -1683,20 +1683,20 @@ void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd)
unsigned long flags;
spin_lock_irqsave(&rq->lock, flags);
__update_group_shares_cpu(tg, sd, i);
__update_group_shares_cpu(tg, cpu, sd, i);
spin_unlock_irqrestore(&rq->lock, flags);
}
aggregate_group_shares(tg, sd);
aggregate_group_shares(tg, cpu, sd);
/*
* ensure we never loose shares due to rounding errors in the
* above redistribution.
*/
shares -= aggregate(tg, sd)->shares;
shares -= aggregate(tg, cpu)->shares;
if (shares) {
tg->cfs_rq[sd->first_cpu]->shares += shares;
aggregate(tg, sd)->shares += shares;
tg->cfs_rq[cpu]->shares += shares;
aggregate(tg, cpu)->shares += shares;
}
}
@ -1704,21 +1704,21 @@ void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd)
* Calculate the accumulative weight and recursive load of each task group
* while walking down the tree.
*/
static
void aggregate_get_down(struct task_group *tg, struct sched_domain *sd)
static void
aggregate_get_down(struct task_group *tg, int cpu, struct sched_domain *sd)
{
aggregate_group_weight(tg, sd);
aggregate_group_shares(tg, sd);
aggregate_group_load(tg, sd);
aggregate_group_weight(tg, cpu, sd);
aggregate_group_shares(tg, cpu, sd);
aggregate_group_load(tg, cpu, sd);
}
/*
* Rebalance the cpu shares while walking back up the tree.
*/
static
void aggregate_get_up(struct task_group *tg, struct sched_domain *sd)
static void
aggregate_get_up(struct task_group *tg, int cpu, struct sched_domain *sd)
{
aggregate_group_set_shares(tg, sd);
aggregate_group_set_shares(tg, cpu, sd);
}
static DEFINE_PER_CPU(spinlock_t, aggregate_lock);
@ -1731,18 +1731,18 @@ static void __init init_aggregate(void)
spin_lock_init(&per_cpu(aggregate_lock, i));
}
static int get_aggregate(struct sched_domain *sd)
static int get_aggregate(int cpu, struct sched_domain *sd)
{
if (!spin_trylock(&per_cpu(aggregate_lock, sd->first_cpu)))
if (!spin_trylock(&per_cpu(aggregate_lock, cpu)))
return 0;
aggregate_walk_tree(aggregate_get_down, aggregate_get_up, sd);
aggregate_walk_tree(aggregate_get_down, aggregate_get_up, cpu, sd);
return 1;
}
static void put_aggregate(struct sched_domain *sd)
static void put_aggregate(int cpu, struct sched_domain *sd)
{
spin_unlock(&per_cpu(aggregate_lock, sd->first_cpu));
spin_unlock(&per_cpu(aggregate_lock, cpu));
}
static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
@ -1756,12 +1756,12 @@ static inline void init_aggregate(void)
{
}
static inline int get_aggregate(struct sched_domain *sd)
static inline int get_aggregate(int cpu, struct sched_domain *sd)
{
return 0;
}
static inline void put_aggregate(struct sched_domain *sd)
static inline void put_aggregate(int cpu, struct sched_domain *sd)
{
}
#endif
@ -3539,7 +3539,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
cpus_setall(*cpus);
unlock_aggregate = get_aggregate(sd);
unlock_aggregate = get_aggregate(this_cpu, sd);
/*
* When power savings policy is enabled for the parent domain, idle
@ -3678,7 +3678,7 @@ out_one_pinned:
ld_moved = 0;
out:
if (unlock_aggregate)
put_aggregate(sd);
put_aggregate(this_cpu, sd);
return ld_moved;
}
@ -7292,7 +7292,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
SD_INIT(sd, ALLNODES);
set_domain_attribute(sd, attr);
sd->span = *cpu_map;
sd->first_cpu = first_cpu(sd->span);
cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
p = sd;
sd_allnodes = 1;
@ -7303,7 +7302,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
SD_INIT(sd, NODE);
set_domain_attribute(sd, attr);
sched_domain_node_span(cpu_to_node(i), &sd->span);
sd->first_cpu = first_cpu(sd->span);
sd->parent = p;
if (p)
p->child = sd;
@ -7315,7 +7313,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
SD_INIT(sd, CPU);
set_domain_attribute(sd, attr);
sd->span = *nodemask;
sd->first_cpu = first_cpu(sd->span);
sd->parent = p;
if (p)
p->child = sd;
@ -7327,7 +7324,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
SD_INIT(sd, MC);
set_domain_attribute(sd, attr);
sd->span = cpu_coregroup_map(i);
sd->first_cpu = first_cpu(sd->span);
cpus_and(sd->span, sd->span, *cpu_map);
sd->parent = p;
p->child = sd;
@ -7340,7 +7336,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map,
SD_INIT(sd, SIBLING);
set_domain_attribute(sd, attr);
sd->span = per_cpu(cpu_sibling_map, i);
sd->first_cpu = first_cpu(sd->span);
cpus_and(sd->span, sd->span, *cpu_map);
sd->parent = p;
p->child = sd;

12
kernel/sched_fair.c
View File

@ -1429,11 +1429,11 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
/*
* empty group
*/
if (!aggregate(tg, sd)->task_weight)
if (!aggregate(tg, this_cpu)->task_weight)
continue;
rem_load = rem_load_move * aggregate(tg, sd)->rq_weight;
rem_load /= aggregate(tg, sd)->load + 1;
rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight;
rem_load /= aggregate(tg, this_cpu)->load + 1;
this_weight = tg->cfs_rq[this_cpu]->task_weight;
busiest_weight = tg->cfs_rq[busiest_cpu]->task_weight;
@ -1451,10 +1451,10 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
if (!moved_load)
continue;
move_group_shares(tg, sd, busiest_cpu, this_cpu);
move_group_shares(tg, this_cpu, sd, busiest_cpu, this_cpu);
moved_load *= aggregate(tg, sd)->load;
moved_load /= aggregate(tg, sd)->rq_weight + 1;
moved_load *= aggregate(tg, this_cpu)->load;
moved_load /= aggregate(tg, this_cpu)->rq_weight + 1;
rem_load_move -= moved_load;
if (rem_load_move < 0)