From 145d952a29320dea883246bcb24ba1da7ac4bb7f Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Thu, 4 Oct 2018 14:04:02 +0200 Subject: [PATCH 1/5] sched: Factor out nr_iowait and nr_iowait_cpu The function nr_iowait_cpu() can be used directly by nr_iowait() instead of duplicating code. Call nr_iowait_cpu() from nr_iowait() Signed-off-by: Daniel Lezcano Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki --- kernel/sched/core.c | 41 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 21 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fe0223121883..9245c56b8f5f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2875,6 +2875,25 @@ unsigned long long nr_context_switches(void) return sum; } +/* + * Consumers of these two interfaces, like for example the cpuidle menu + * governor, are using nonsensical data. Preferring shallow idle state selection + * for a CPU that has IO-wait which might not even end up running the task when + * it does become runnable. + */ + +unsigned long nr_iowait_cpu(int cpu) +{ + return atomic_read(&cpu_rq(cpu)->nr_iowait); +} + +void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) +{ + struct rq *rq = this_rq(); + *nr_waiters = atomic_read(&rq->nr_iowait); + *load = rq->load.weight; +} + /* * IO-wait accounting, and how its mostly bollocks (on SMP). * @@ -2910,31 +2929,11 @@ unsigned long nr_iowait(void) unsigned long i, sum = 0; for_each_possible_cpu(i) - sum += atomic_read(&cpu_rq(i)->nr_iowait); + sum += nr_iowait_cpu(i); return sum; } -/* - * Consumers of these two interfaces, like for example the cpuidle menu - * governor, are using nonsensical data. Preferring shallow idle state selection - * for a CPU that has IO-wait which might not even end up running the task when - * it does become runnable. - */ - -unsigned long nr_iowait_cpu(int cpu) -{ - struct rq *this = cpu_rq(cpu); - return atomic_read(&this->nr_iowait); -} - -void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) -{ - struct rq *rq = this_rq(); - *nr_waiters = atomic_read(&rq->nr_iowait); - *load = rq->load.weight; -} - #ifdef CONFIG_SMP /* From a7fe5190c03f8137ef08db84a58dd4daf2c4785d Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Thu, 4 Oct 2018 14:04:03 +0200 Subject: [PATCH 2/5] cpuidle: menu: Remove get_loadavg() from the performance multiplier The function get_loadavg() returns almost always zero. To be more precise, statistically speaking for a total of 1023379 times passing in the function, the load is equal to zero 1020728 times, greater than 100, 610 times, the remaining is between 0 and 5. In 2011, the get_loadavg() was removed from the Android tree because of the above [1]. At this time, the load was: unsigned long this_cpu_load(void) { struct rq *this = this_rq(); return this->cpu_load[0]; } In 2014, the code was changed by commit 372ba8cb46b2 (cpuidle: menu: Lookup CPU runqueues less) and the load is: void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) { struct rq *rq = this_rq(); *nr_waiters = atomic_read(&rq->nr_iowait); *load = rq->load.weight; } with the same result. Both measurements show using the load in this code path does no matter anymore. Removing it. [1] https://android.googlesource.com/kernel/common/+/4dedd9f124703207895777ac6e91dacde0f7cc17 Signed-off-by: Daniel Lezcano Acked-by: Mel Gorman Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/governors/menu.c | 25 ++++++------------------- include/linux/sched/stat.h | 1 - kernel/sched/core.c | 7 ------- 3 files changed, 6 insertions(+), 27 deletions(-) diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index 575a68f31761..76df4f947f07 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -134,11 +134,6 @@ struct menu_device { #define LOAD_INT(x) ((x) >> FSHIFT) #define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100) -static inline int get_loadavg(unsigned long load) -{ - return LOAD_INT(load) * 10 + LOAD_FRAC(load) / 10; -} - static inline int which_bucket(unsigned int duration, unsigned long nr_iowaiters) { int bucket = 0; @@ -172,18 +167,10 @@ static inline int which_bucket(unsigned int duration, unsigned long nr_iowaiters * to be, the higher this multiplier, and thus the higher * the barrier to go to an expensive C state. */ -static inline int performance_multiplier(unsigned long nr_iowaiters, unsigned long load) +static inline int performance_multiplier(unsigned long nr_iowaiters) { - int mult = 1; - - /* for higher loadavg, we are more reluctant */ - - mult += 2 * get_loadavg(load); - - /* for IO wait tasks (per cpu!) we add 5x each */ - mult += 10 * nr_iowaiters; - - return mult; + /* for IO wait tasks (per cpu!) we add 10x each */ + return 1 + 10 * nr_iowaiters; } static DEFINE_PER_CPU(struct menu_device, menu_devices); @@ -301,7 +288,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, int idx; unsigned int interactivity_req; unsigned int predicted_us; - unsigned long nr_iowaiters, cpu_load; + unsigned long nr_iowaiters; ktime_t delta_next; if (data->needs_update) { @@ -312,7 +299,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, /* determine the expected residency time, round up */ data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length(&delta_next)); - get_iowait_load(&nr_iowaiters, &cpu_load); + nr_iowaiters = nr_iowait_cpu(dev->cpu); data->bucket = which_bucket(data->next_timer_us, nr_iowaiters); if (unlikely(drv->state_count <= 1 || latency_req == 0) || @@ -356,7 +343,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, * Use the performance multiplier and the user-configurable * latency_req to determine the maximum exit latency. */ - interactivity_req = predicted_us / performance_multiplier(nr_iowaiters, cpu_load); + interactivity_req = predicted_us / performance_multiplier(nr_iowaiters); if (latency_req > interactivity_req) latency_req = interactivity_req; } diff --git a/include/linux/sched/stat.h b/include/linux/sched/stat.h index 04f1321d14c4..f30954cc059d 100644 --- a/include/linux/sched/stat.h +++ b/include/linux/sched/stat.h @@ -20,7 +20,6 @@ extern unsigned long nr_running(void); extern bool single_task_running(void); extern unsigned long nr_iowait(void); extern unsigned long nr_iowait_cpu(int cpu); -extern void get_iowait_load(unsigned long *nr_waiters, unsigned long *load); static inline int sched_info_on(void) { diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 9245c56b8f5f..c8d5c279be14 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2887,13 +2887,6 @@ unsigned long nr_iowait_cpu(int cpu) return atomic_read(&cpu_rq(cpu)->nr_iowait); } -void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) -{ - struct rq *rq = this_rq(); - *nr_waiters = atomic_read(&rq->nr_iowait); - *load = rq->load.weight; -} - /* * IO-wait accounting, and how its mostly bollocks (on SMP). * From 5906056e52e9ee5e130d880443e83016f892b5dd Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Tue, 23 Oct 2018 21:54:04 +0200 Subject: [PATCH 3/5] cpufreq: intel_pstate: Fix compilation for !CONFIG_ACPI While at it, add a few comments which config options #ifdef and #else statements refer to. Fixes: 86d333a8cc7f (cpufreq: intel_pstate: Add base_frequency attribute) Signed-off-by: Dominik Brodowski Acked-by: Srinivas Pandruvada Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/intel_pstate.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 49c0abf2d48f..9578312e43f2 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -386,16 +386,11 @@ static int intel_pstate_get_cppc_guranteed(int cpu) return cppc_perf.guaranteed_perf; } -#else +#else /* CONFIG_ACPI_CPPC_LIB */ static void intel_pstate_set_itmt_prio(int cpu) { } - -static int intel_pstate_get_cppc_guranteed(int cpu) -{ - return -ENOTSUPP; -} -#endif +#endif /* CONFIG_ACPI_CPPC_LIB */ static void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy) { @@ -477,7 +472,7 @@ static void intel_pstate_exit_perf_limits(struct cpufreq_policy *policy) acpi_processor_unregister_performance(policy->cpu); } -#else +#else /* CONFIG_ACPI */ static inline void intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy) { } @@ -490,7 +485,14 @@ static inline bool intel_pstate_acpi_pm_profile_server(void) { return false; } -#endif +#endif /* CONFIG_ACPI */ + +#ifndef CONFIG_ACPI_CPPC_LIB +static int intel_pstate_get_cppc_guranteed(int cpu) +{ + return -ENOTSUPP; +} +#endif /* CONFIG_ACPI_CPPC_LIB */ static inline void update_turbo_state(void) { From a7314405d83c8f95736edb0ea7ade5d459b79afe Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 24 Oct 2018 14:44:57 +0100 Subject: [PATCH 4/5] cpufreq: drop ARM_BIG_LITTLE_CPUFREQ support for ARM64 ARM_BIG_LITTLE_CPUFREQ depends on topology_physical_package_id to get the cluster id which inturn provides the information on related cpus in the same performance domain. ARM64 core doesn't provide the cluster information as it's not architecturally defined. There are no users of this driver in ARM64 after the one and only user(SCPI) moved away. So let's ban the usage of this driver for ARM64. Signed-off-by: Sudeep Holla Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/Kconfig.arm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 0cd8eb76ad59..040cfedf3e37 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -28,7 +28,7 @@ config ARM_ARMADA_37XX_CPUFREQ # big LITTLE core layer and glue drivers config ARM_BIG_LITTLE_CPUFREQ tristate "Generic ARM big LITTLE CPUfreq driver" - depends on (ARM_CPU_TOPOLOGY || ARM64) && HAVE_CLK + depends on ARM_CPU_TOPOLOGY && HAVE_CLK # if CPU_THERMAL is on and THERMAL=m, ARM_BIT_LITTLE_CPUFREQ cannot be =y depends on !CPU_THERMAL || THERMAL select PM_OPP From f174e49e4906d945a0e4de98fbf796de31614f47 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 24 Oct 2018 14:44:58 +0100 Subject: [PATCH 5/5] cpufreq: remove unused arm_big_little_dt driver Most of the ARM platforms used cpufreq-dt driver irrespective of whether it's big-little(HMP) or SMP system. This arm_big_little_dt is not used actively at all. So let's remove the driver, so that it need not be maintained. Signed-off-by: Sudeep Holla Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- MAINTAINERS | 1 - drivers/cpufreq/Kconfig.arm | 7 -- drivers/cpufreq/Makefile | 3 - drivers/cpufreq/arm_big_little_dt.c | 100 ---------------------------- 4 files changed, 111 deletions(-) delete mode 100644 drivers/cpufreq/arm_big_little_dt.c diff --git a/MAINTAINERS b/MAINTAINERS index 16fb17ce1475..874cc7a54e56 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3838,7 +3838,6 @@ W: http://www.arm.com/products/processors/technologies/biglittleprocessing.php S: Maintained F: drivers/cpufreq/arm_big_little.h F: drivers/cpufreq/arm_big_little.c -F: drivers/cpufreq/arm_big_little_dt.c CPU POWER MONITORING SUBSYSTEM M: Thomas Renninger diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 040cfedf3e37..4e1131ef85ae 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -35,13 +35,6 @@ config ARM_BIG_LITTLE_CPUFREQ help This enables the Generic CPUfreq driver for ARM big.LITTLE platforms. -config ARM_DT_BL_CPUFREQ - tristate "Generic probing via DT for ARM big LITTLE CPUfreq driver" - depends on ARM_BIG_LITTLE_CPUFREQ && OF - help - This enables probing via DT for Generic CPUfreq driver for ARM - big.LITTLE platform. This gets frequency tables from DT. - config ARM_SCPI_CPUFREQ tristate "SCPI based CPUfreq driver" depends on ARM_SCPI_PROTOCOL && COMMON_CLK_SCPI diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index c1ffeabe4ecf..d5ee4562ed06 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -48,9 +48,6 @@ obj-$(CONFIG_X86_SFI_CPUFREQ) += sfi-cpufreq.o ################################################################################## # ARM SoC drivers obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ) += arm_big_little.o -# big LITTLE per platform glues. Keep DT_BL_CPUFREQ as the last entry in all big -# LITTLE drivers, so that it is probed last. -obj-$(CONFIG_ARM_DT_BL_CPUFREQ) += arm_big_little_dt.o obj-$(CONFIG_ARM_ARMADA_37XX_CPUFREQ) += armada-37xx-cpufreq.o obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ) += brcmstb-avs-cpufreq.o diff --git a/drivers/cpufreq/arm_big_little_dt.c b/drivers/cpufreq/arm_big_little_dt.c deleted file mode 100644 index b944f290c8a4..000000000000 --- a/drivers/cpufreq/arm_big_little_dt.c +++ /dev/null @@ -1,100 +0,0 @@ -/* - * Generic big.LITTLE CPUFreq Interface driver - * - * It provides necessary ops to arm_big_little cpufreq driver and gets - * Frequency information from Device Tree. Freq table in DT must be in KHz. - * - * Copyright (C) 2013 Linaro. - * Viresh Kumar - * - * 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. - * - * This program is distributed "as is" WITHOUT ANY WARRANTY of any - * kind, whether express or implied; without even the implied warranty - * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - */ - -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include "arm_big_little.h" - -/* get cpu node with valid operating-points */ -static struct device_node *get_cpu_node_with_valid_op(int cpu) -{ - struct device_node *np = of_cpu_device_node_get(cpu); - - if (!of_get_property(np, "operating-points", NULL)) { - of_node_put(np); - np = NULL; - } - - return np; -} - -static int dt_get_transition_latency(struct device *cpu_dev) -{ - struct device_node *np; - u32 transition_latency = CPUFREQ_ETERNAL; - - np = of_node_get(cpu_dev->of_node); - if (!np) { - pr_info("Failed to find cpu node. Use CPUFREQ_ETERNAL transition latency\n"); - return CPUFREQ_ETERNAL; - } - - of_property_read_u32(np, "clock-latency", &transition_latency); - of_node_put(np); - - pr_debug("%s: clock-latency: %d\n", __func__, transition_latency); - return transition_latency; -} - -static const struct cpufreq_arm_bL_ops dt_bL_ops = { - .name = "dt-bl", - .get_transition_latency = dt_get_transition_latency, - .init_opp_table = dev_pm_opp_of_cpumask_add_table, - .free_opp_table = dev_pm_opp_of_cpumask_remove_table, -}; - -static int generic_bL_probe(struct platform_device *pdev) -{ - struct device_node *np; - - np = get_cpu_node_with_valid_op(0); - if (!np) - return -ENODEV; - - of_node_put(np); - return bL_cpufreq_register(&dt_bL_ops); -} - -static int generic_bL_remove(struct platform_device *pdev) -{ - bL_cpufreq_unregister(&dt_bL_ops); - return 0; -} - -static struct platform_driver generic_bL_platdrv = { - .driver = { - .name = "arm-bL-cpufreq-dt", - }, - .probe = generic_bL_probe, - .remove = generic_bL_remove, -}; -module_platform_driver(generic_bL_platdrv); - -MODULE_AUTHOR("Viresh Kumar "); -MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT"); -MODULE_LICENSE("GPL v2");