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-rw-r--r--include/linux/sched.h1
-rw-r--r--include/linux/topology.h1
-rw-r--r--kernel/sched.c8
3 files changed, 9 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 651dded25720..9c81c921acb3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -921,6 +921,7 @@ struct sched_domain {
unsigned int newidle_idx;
unsigned int wake_idx;
unsigned int forkexec_idx;
+ unsigned int smt_gain;
int flags; /* See SD_* */
enum sched_domain_level level;
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 7402c1a27c4f..6203ae5067ce 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -99,6 +99,7 @@ int arch_update_cpu_topology(void);
| SD_SHARE_CPUPOWER, \
.last_balance = jiffies, \
.balance_interval = 1, \
+ .smt_gain = 1178, /* 15% */ \
}
#endif
#endif /* CONFIG_SCHED_SMT */
diff --git a/kernel/sched.c b/kernel/sched.c
index ecb4a47d4214..55112261027b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8523,9 +8523,15 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd)
weight = cpumask_weight(sched_domain_span(sd));
/*
* SMT siblings share the power of a single core.
+ * Usually multiple threads get a better yield out of
+ * that one core than a single thread would have,
+ * reflect that in sd->smt_gain.
*/
- if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1)
+ if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
+ power *= sd->smt_gain;
power /= weight;
+ power >>= SCHED_LOAD_SHIFT;
+ }
sg_inc_cpu_power(sd->groups, power);
return;
}