From 63b2ca30bdb3dbf60bc7ac5f46713c0d32308261 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Mon, 26 May 2014 18:19:37 -0400 Subject: sched: Let 'struct sched_group_power' care about CPU capacity It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. Since struct sched_group_power is really about compute capacity of sched groups, let's rename it to struct sched_group_capacity. Similarly sgp becomes sgc. Related variables and functions dealing with groups are also adjusted accordingly. Signed-off-by: Nicolas Pitre Signed-off-by: Peter Zijlstra Cc: Vincent Guittot Cc: Daniel Lezcano Cc: Morten Rasmussen Cc: "Rafael J. Wysocki" Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-5yeix833vvgf2uyj5o36hpu9@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/sched.h | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'kernel/sched/sched.h') diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 600e2291a75c..a5b957d53c92 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -728,15 +728,15 @@ DECLARE_PER_CPU(struct sched_domain *, sd_numa); DECLARE_PER_CPU(struct sched_domain *, sd_busy); DECLARE_PER_CPU(struct sched_domain *, sd_asym); -struct sched_group_power { +struct sched_group_capacity { atomic_t ref; /* - * CPU power of this group, SCHED_LOAD_SCALE being max power for a - * single CPU. + * CPU capacity of this group, SCHED_LOAD_SCALE being max capacity + * for a single CPU. */ - unsigned int power, power_orig; + unsigned int capacity, capacity_orig; unsigned long next_update; - int imbalance; /* XXX unrelated to power but shared group state */ + int imbalance; /* XXX unrelated to capacity but shared group state */ /* * Number of busy cpus in this group. */ @@ -750,7 +750,7 @@ struct sched_group { atomic_t ref; unsigned int group_weight; - struct sched_group_power *sgp; + struct sched_group_capacity *sgc; /* * The CPUs this group covers. @@ -773,7 +773,7 @@ static inline struct cpumask *sched_group_cpus(struct sched_group *sg) */ static inline struct cpumask *sched_group_mask(struct sched_group *sg) { - return to_cpumask(sg->sgp->cpumask); + return to_cpumask(sg->sgc->cpumask); } /** @@ -1167,7 +1167,7 @@ extern const struct sched_class idle_sched_class; #ifdef CONFIG_SMP -extern void update_group_power(struct sched_domain *sd, int cpu); +extern void update_group_capacity(struct sched_domain *sd, int cpu); extern void trigger_load_balance(struct rq *rq); -- cgit v1.2.1 From ced549fa5fc1fdaf7fac93894dc673092eb3dc20 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Mon, 26 May 2014 18:19:38 -0400 Subject: sched: Remove remaining dubious usage of "power" It is better not to think about compute capacity as being equivalent to "CPU power". The upcoming "power aware" scheduler work may create confusion with the notion of energy consumption if "power" is used too liberally. This is the remaining "power" -> "capacity" rename for local symbols. Those symbols visible to the rest of the kernel are not included yet. Signed-off-by: Nicolas Pitre Signed-off-by: Peter Zijlstra Cc: Vincent Guittot Cc: Daniel Lezcano Cc: Morten Rasmussen Cc: "Rafael J. Wysocki" Cc: linaro-kernel@lists.linaro.org Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-yyyhohzhkwnaotr3lx8zd5aa@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sched/sched.h') diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index a5b957d53c92..956b8ca24893 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -567,7 +567,7 @@ struct rq { struct root_domain *rd; struct sched_domain *sd; - unsigned long cpu_power; + unsigned long cpu_capacity; unsigned char idle_balance; /* For active balancing */ -- cgit v1.2.1 From e3baac47f0e82c4be632f4f97215bb93bf16b342 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 4 Jun 2014 10:31:18 -0700 Subject: sched/idle: Optimize try-to-wake-up IPI [ This series reduces the number of IPIs on Andy's workload by something like 99%. It's down from many hundreds per second to very few. The basic idea behind this series is to make TIF_POLLING_NRFLAG be a reliable indication that the idle task is polling. Once that's done, the rest is reasonably straightforward. ] When enqueueing tasks on remote LLC domains, we send an IPI to do the work 'locally' and avoid bouncing all the cachelines over. However, when the remote CPU is idle (and polling, say x86 mwait), we don't need to send an IPI, we can simply kick the TIF word to wake it up and have the 'idle' loop do the work. So when _TIF_POLLING_NRFLAG is set, but _TIF_NEED_RESCHED is not (yet) set, set _TIF_NEED_RESCHED and avoid sending the IPI. Much-requested-by: Andy Lutomirski Signed-off-by: Peter Zijlstra [Edited by Andy Lutomirski, but this is mostly Peter Zijlstra's code.] Signed-off-by: Andy Lutomirski Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: Mike Galbraith Cc: umgwanakikbuti@gmail.com Cc: Rafael J. Wysocki Cc: Linus Torvalds Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/ce06f8b02e7e337be63e97597fc4b248d3aa6f9b.1401902905.git.luto@amacapital.net Signed-off-by: Ingo Molnar --- kernel/sched/sched.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/sched/sched.h') diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 956b8ca24893..2f8636199b83 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -670,6 +670,8 @@ extern int migrate_swap(struct task_struct *, struct task_struct *); #ifdef CONFIG_SMP +extern void sched_ttwu_pending(void); + #define rcu_dereference_check_sched_domain(p) \ rcu_dereference_check((p), \ lockdep_is_held(&sched_domains_mutex)) @@ -787,6 +789,10 @@ static inline unsigned int group_first_cpu(struct sched_group *group) extern int group_balance_cpu(struct sched_group *sg); +#else + +static inline void sched_ttwu_pending(void) { } + #endif /* CONFIG_SMP */ #include "stats.h" -- cgit v1.2.1