Infrastructure for power driver registration and defines three initial power driver interface calls: go_faster(), go_slower(), and at_max_capacity(). The intention is to use these to guide scheduling decisions and frequency state selection in the power driver.
Signed-off-by: Morten Rasmussen morten.rasmussen@arm.com --- arch/arm/Kconfig | 4 +++ include/linux/sched/power.h | 32 ++++++++++++++++++++++++ kernel/sched/Makefile | 1 + kernel/sched/power.c | 58 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 95 insertions(+) create mode 100644 include/linux/sched/power.h create mode 100644 kernel/sched/power.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 43594d5..763d147 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1844,6 +1844,10 @@ config XEN help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM.
+config SCHED_POWER + bool "(EXPERIMENTAL) Power aware scheduling" + default n + endmenu
menu "Boot options" diff --git a/include/linux/sched/power.h b/include/linux/sched/power.h new file mode 100644 index 0000000..cb2cf37 --- /dev/null +++ b/include/linux/sched/power.h @@ -0,0 +1,32 @@ +/* + * include/linux/sched/power.h + * + * Copyright (C) 2013 ARM Limited. + * Author: Morten Rasmussen morten.rasmussen@arm.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef _LINUX_SCHED_POWER_H +#define _LINUX_SCHED_POWER_H + +struct power_driver { + + /* + * Power driver calls may happen from scheduler context with irq + * disabled and rq locks held. This must be taken into account in the + * power driver. + */ + + /* cpu already at max capacity? */ + int (*at_max_capacity) (int cpu); + /* Increase cpu capacity hint */ + int (*go_faster) (int cpu, int hint); + /* Decrease cpu capacity hint */ + int (*go_slower) (int cpu, int hint); +}; + +int power_driver_register(struct power_driver *driver); +int power_driver_unregister(struct power_driver *driver); +#endif diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 54adcf3..55727b4 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -17,3 +17,4 @@ obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o obj-$(CONFIG_SCHEDSTATS) += stats.o obj-$(CONFIG_SCHED_DEBUG) += debug.o obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o +obj-$(CONFIG_SCHED_POWER) += power.o diff --git a/kernel/sched/power.c b/kernel/sched/power.c new file mode 100644 index 0000000..b82965a --- /dev/null +++ b/kernel/sched/power.c @@ -0,0 +1,58 @@ +/* + * kernel/sched/power.c + * + * Copyright (C) 2013 ARM Limited. + * Author: Morten Rasmussen morten.rasmussen@arm.com + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/kernel.h> +#include <linux/sched/power.h> + +static struct power_driver *power_driver; + +int power_driver_register(struct power_driver *driver) +{ + power_driver = driver; + + return 1; +} + +int power_driver_unregister(struct power_driver *driver) +{ + power_driver = NULL; + + return 1; +} + +int at_max_capacity(int cpu) +{ + /* Assume no performance scaling when no driver */ + if (!power_driver) + return 1; + + return power_driver->at_max_capacity(cpu); +} + +int go_faster(int cpu, int hint) +{ + /* Assume no performance scaling when no driver */ + if (!power_driver) + return 0; + + return power_driver->go_faster(cpu, hint); +} + +int go_slower(int cpu, int hint) +{ + /* Assume no performance scaling when no driver */ + if (!power_driver) + return 0; + + return power_driver->go_slower(cpu, hint); +} +