diff options
| author | Jason Low <jason.low2@hp.com> | 2013-09-13 18:26:53 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-09-20 10:03:46 (GMT) |
| commit | f48627e686a69f5215cb0761e731edb3d9859dd9 (patch) | |
| tree | 510f55a0971da16bdb2922da2c0ebad47bdc5e3d /kernel/sched/fair.c | |
| parent | 9bd721c55c8a886b938a45198aab0ccb52f1f7fa (diff) | |
| download | linux-f48627e686a69f5215cb0761e731edb3d9859dd9.tar.xz | |
sched/balancing: Periodically decay max cost of idle balance
This patch builds on patch 2 and periodically decays that max value to
do idle balancing per sched domain by approximately 1% per second. Also
decay the rq's max_idle_balance_cost value.
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1379096813-3032-4-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 38 |
1 files changed, 31 insertions, 7 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ffc99d8..2b89cd2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5681,15 +5681,39 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) /* Earliest time when we have to do rebalance again */ unsigned long next_balance = jiffies + 60*HZ; int update_next_balance = 0; - int need_serialize; + int need_serialize, need_decay = 0; + u64 max_cost = 0; update_blocked_averages(cpu); rcu_read_lock(); for_each_domain(cpu, sd) { + /* + * Decay the newidle max times here because this is a regular + * visit to all the domains. Decay ~1% per second. + */ + if (time_after(jiffies, sd->next_decay_max_lb_cost)) { + sd->max_newidle_lb_cost = + (sd->max_newidle_lb_cost * 253) / 256; + sd->next_decay_max_lb_cost = jiffies + HZ; + need_decay = 1; + } + max_cost += sd->max_newidle_lb_cost; + if (!(sd->flags & SD_LOAD_BALANCE)) continue; + /* + * Stop the load balance at this level. There is another + * CPU in our sched group which is doing load balancing more + * actively. + */ + if (!continue_balancing) { + if (need_decay) + continue; + break; + } + interval = sd->balance_interval; if (idle != CPU_IDLE) interval *= sd->busy_factor; @@ -5723,14 +5747,14 @@ out: next_balance = sd->last_balance + interval; update_next_balance = 1; } - + } + if (need_decay) { /* - * Stop the load balance at this level. There is another - * CPU in our sched group which is doing load balancing more - * actively. + * Ensure the rq-wide value also decays but keep it at a + * reasonable floor to avoid funnies with rq->avg_idle. */ - if (!continue_balancing) - break; + rq->max_idle_balance_cost = + max((u64)sysctl_sched_migration_cost, max_cost); } rcu_read_unlock(); |