Commit-ID: 011b27bb5d3139e8b5fe9ceff1fc7f6dc3145071 Gitweb: https://git.kernel.org/tip/011b27bb5d3139e8b5fe9ceff1fc7f6dc3145071 Author: Quentin Perret <[email protected]> AuthorDate: Mon, 3 Dec 2018 09:56:19 +0000 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 11 Dec 2018 15:16:59 +0100
sched/topology: Add lowest CPU asymmetry sched_domain level pointer Add another member to the family of per-cpu sched_domain shortcut pointers. This one, sd_asym_cpucapacity, points to the lowest level at which the SD_ASYM_CPUCAPACITY flag is set. While at it, rename the sd_asym shortcut to sd_asym_packing to avoid confusions. Generally speaking, the largest opportunity to save energy via scheduling comes from a smarter exploitation of heterogeneous platforms (i.e. big.LITTLE). Consequently, the sd_asym_cpucapacity shortcut will be used at first as the lowest domain where Energy-Aware Scheduling (EAS) should be applied. For example, it is possible to apply EAS within a socket on a multi-socket system, as long as each socket has an asymmetric topology. Energy-aware cross-sockets wake-up balancing will only happen when the system is over-utilized, or this_cpu and prev_cpu are in different sockets. Suggested-by: Morten Rasmussen <[email protected]> Signed-off-by: Quentin Perret <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- kernel/sched/fair.c | 2 +- kernel/sched/sched.h | 3 ++- kernel/sched/topology.c | 8 ++++++-- 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index fdc8356ea742..a31a6d325901 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9299,7 +9299,7 @@ static void nohz_balancer_kick(struct rq *rq) } } - sd = rcu_dereference(per_cpu(sd_asym, cpu)); + sd = rcu_dereference(per_cpu(sd_asym_packing, cpu)); if (sd) { for_each_cpu(i, sched_domain_span(sd)) { if (i == cpu || diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 808a565187b1..75c403674706 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1303,7 +1303,8 @@ DECLARE_PER_CPU(int, sd_llc_size); DECLARE_PER_CPU(int, sd_llc_id); DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared); DECLARE_PER_CPU(struct sched_domain *, sd_numa); -DECLARE_PER_CPU(struct sched_domain *, sd_asym); +DECLARE_PER_CPU(struct sched_domain *, sd_asym_packing); +DECLARE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity); extern struct static_key_false sched_asym_cpucapacity; struct sched_group_capacity { diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 169d25cafab5..137ccfed9a43 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -508,7 +508,8 @@ DEFINE_PER_CPU(int, sd_llc_size); DEFINE_PER_CPU(int, sd_llc_id); DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared); DEFINE_PER_CPU(struct sched_domain *, sd_numa); -DEFINE_PER_CPU(struct sched_domain *, sd_asym); +DEFINE_PER_CPU(struct sched_domain *, sd_asym_packing); +DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity); DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity); static void update_top_cache_domain(int cpu) @@ -534,7 +535,10 @@ static void update_top_cache_domain(int cpu) rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); sd = highest_flag_domain(cpu, SD_ASYM_PACKING); - rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); + rcu_assign_pointer(per_cpu(sd_asym_packing, cpu), sd); + + sd = lowest_flag_domain(cpu, SD_ASYM_CPUCAPACITY); + rcu_assign_pointer(per_cpu(sd_asym_cpucapacity, cpu), sd); } /*
