From 9bd721c55c8a886b938a45198aab0ccb52f1f7fa Mon Sep 17 00:00:00 2001 From: Jason Low Date: Fri, 13 Sep 2013 11:26:52 -0700 Subject: sched/balancing: Consider max cost of idle balance per sched domain In this patch, we keep track of the max cost we spend doing idle load balancing for each sched domain. If the avg time the CPU remains idle is less then the time we have already spent on idle balancing + the max cost of idle balancing in the sched domain, then we don't continue to attempt the balance. We also keep a per rq variable, max_idle_balance_cost, which keeps track of the max time spent on newidle load balances throughout all its domains so that we can determine the avg_idle's max value. By using the max, we avoid overrunning the average. This further reduces the chance we attempt balancing when the CPU is not idle for longer than the cost to balance. Signed-off-by: Jason Low Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1379096813-3032-3-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + include/linux/topology.h | 3 +++ 2 files changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 6682da36b293..be078ff9157f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -810,6 +810,7 @@ struct sched_domain { unsigned int nr_balance_failed; /* initialise to 0 */ u64 last_update; + u64 max_newidle_lb_cost; #ifdef CONFIG_SCHEDSTATS /* load_balance() stats */ diff --git a/include/linux/topology.h b/include/linux/topology.h index d3cf0d6e7712..e2a2c3da2929 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -106,6 +106,7 @@ int arch_update_cpu_topology(void); .last_balance = jiffies, \ .balance_interval = 1, \ .smt_gain = 1178, /* 15% */ \ + .max_newidle_lb_cost = 0, \ } #endif #endif /* CONFIG_SCHED_SMT */ @@ -135,6 +136,7 @@ int arch_update_cpu_topology(void); , \ .last_balance = jiffies, \ .balance_interval = 1, \ + .max_newidle_lb_cost = 0, \ } #endif #endif /* CONFIG_SCHED_MC */ @@ -166,6 +168,7 @@ int arch_update_cpu_topology(void); , \ .last_balance = jiffies, \ .balance_interval = 1, \ + .max_newidle_lb_cost = 0, \ } #endif -- cgit v1.2.3