Loading drivers/devfreq/Kconfig +9 −0 Original line number Diff line number Diff line Loading @@ -73,6 +73,15 @@ config DEVFREQ_GOV_PASSIVE through sysfs entries. The passive governor recommends that devfreq device uses the OPP table to get the frequency/voltage. config DEVFREQ_GOV_QCOM_CACHE_HWMON tristate "HW monitor based governor for cache frequency" help HW monitor based governor for cache frequency scaling. This governor sets the cache frequency by using PM counters to monitor the CPU's use of cache. Since this governor uses some of the PM counters it can conflict with existing profiling tools. This governor is unlikely to be useful for other devices. comment "DEVFREQ Drivers" config ARM_EXYNOS_BUS_DEVFREQ Loading drivers/devfreq/Makefile +1 −0 Original line number Diff line number Diff line Loading @@ -6,6 +6,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE) += governor_performance.o obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o obj-$(CONFIG_DEVFREQ_GOV_QCOM_CACHE_HWMON) += governor_cache_hwmon.o # DEVFREQ Drivers obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o Loading drivers/devfreq/governor_cache_hwmon.c 0 → 100644 +314 −0 Original line number Diff line number Diff line // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2014, 2019 The Linux Foundation. All rights reserved. */ #define pr_fmt(fmt) "cache-hwmon: " fmt #include <linux/kernel.h> #include <linux/sizes.h> #include <linux/module.h> #include <linux/init.h> #include <linux/io.h> #include <linux/delay.h> #include <linux/ktime.h> #include <linux/time.h> #include <linux/err.h> #include <linux/errno.h> #include <linux/mutex.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/of.h> #include <linux/devfreq.h> #include "governor.h" #include "governor_cache_hwmon.h" #define show_attr(name) \ static ssize_t show_##name(struct device *dev, \ struct device_attribute *attr, char *buf) \ { \ return scnprintf(buf, PAGE_SIZE, "%u\n", name); \ } #define store_attr(name, _min, _max) \ static ssize_t store_##name(struct device *dev, \ struct device_attribute *attr, const char *buf, \ size_t count) \ { \ int ret; \ unsigned int val; \ ret = kstrtoint(buf, 10, &val); \ if (ret) \ return ret; \ val = max(val, _min); \ val = min(val, _max); \ name = val; \ return count; \ } #define gov_attr(__attr, min, max) \ show_attr(__attr) \ store_attr(__attr, (min), (max)) \ static DEVICE_ATTR(__attr, 0644, show_##__attr, store_##__attr) static struct cache_hwmon *hw; static unsigned int cycles_per_low_req; static unsigned int cycles_per_med_req = 20; static unsigned int cycles_per_high_req = 35; static unsigned int min_busy = 100; static unsigned int max_busy = 100; static unsigned int tolerance_mrps = 5; static unsigned int guard_band_mhz = 100; static unsigned int decay_rate = 90; #define MIN_MS 10U #define MAX_MS 500U static unsigned int sample_ms = 50; static unsigned long prev_mhz; static ktime_t prev_ts; static unsigned long measure_mrps_and_set_irq(struct devfreq *df, struct mrps_stats *stat) { ktime_t ts; unsigned int us; /* * Since we are stopping the counters, we don't want this short work * to be interrupted by other tasks and cause the measurements to be * wrong. Not blocking interrupts to avoid affecting interrupt * latency and since they should be short anyway because they run in * atomic context. */ preempt_disable(); ts = ktime_get(); us = ktime_to_us(ktime_sub(ts, prev_ts)); if (!us) us = 1; hw->meas_mrps_and_set_irq(df, tolerance_mrps, us, stat); prev_ts = ts; preempt_enable(); pr_debug("stat H=%3lu, M=%3lu, T=%3lu, b=%3u, f=%4lu, us=%d\n", stat->high, stat->med, stat->high + stat->med, stat->busy_percent, df->previous_freq / 1000, us); return 0; } static void compute_cache_freq(struct mrps_stats *mrps, unsigned long *freq) { unsigned long new_mhz; unsigned int busy; new_mhz = mrps->high * cycles_per_high_req + mrps->med * cycles_per_med_req + mrps->low * cycles_per_low_req; busy = max(min_busy, mrps->busy_percent); busy = min(max_busy, busy); new_mhz *= 100; new_mhz /= busy; if (new_mhz < prev_mhz) { new_mhz = new_mhz * decay_rate + prev_mhz * (100 - decay_rate); new_mhz /= 100; } prev_mhz = new_mhz; new_mhz += guard_band_mhz; *freq = new_mhz * 1000; } #define TOO_SOON_US (1 * USEC_PER_MSEC) static irqreturn_t mon_intr_handler(int irq, void *dev) { struct devfreq *df = dev; ktime_t ts; unsigned int us; int ret; if (!hw->is_valid_irq(df)) return IRQ_NONE; pr_debug("Got interrupt\n"); devfreq_monitor_stop(df); /* * Don't recalc cache freq if the interrupt comes right after a * previous cache freq calculation. This is done for two reasons: * * 1. Sampling the cache request during a very short duration can * result in a very inaccurate measurement due to very short * bursts. * 2. This can only happen if the limit was hit very close to the end * of the previous sample period. Which means the current cache * request estimate is not very off and doesn't need to be * readjusted. */ ts = ktime_get(); us = ktime_to_us(ktime_sub(ts, prev_ts)); if (us > TOO_SOON_US) { mutex_lock(&df->lock); ret = update_devfreq(df); if (ret) pr_err("Unable to update freq on IRQ!\n"); mutex_unlock(&df->lock); } devfreq_monitor_start(df); return IRQ_HANDLED; } static int devfreq_cache_hwmon_get_freq(struct devfreq *df, unsigned long *freq) { struct mrps_stats stat; measure_mrps_and_set_irq(df, &stat); compute_cache_freq(&stat, freq); return 0; } gov_attr(cycles_per_low_req, 1U, 100U); gov_attr(cycles_per_med_req, 1U, 100U); gov_attr(cycles_per_high_req, 1U, 100U); gov_attr(min_busy, 1U, 100U); gov_attr(max_busy, 1U, 100U); gov_attr(tolerance_mrps, 0U, 100U); gov_attr(guard_band_mhz, 0U, 500U); gov_attr(decay_rate, 0U, 100U); static struct attribute *dev_attr[] = { &dev_attr_cycles_per_low_req.attr, &dev_attr_cycles_per_med_req.attr, &dev_attr_cycles_per_high_req.attr, &dev_attr_min_busy.attr, &dev_attr_max_busy.attr, &dev_attr_tolerance_mrps.attr, &dev_attr_guard_band_mhz.attr, &dev_attr_decay_rate.attr, NULL, }; static struct attribute_group dev_attr_group = { .name = "cache_hwmon", .attrs = dev_attr, }; static int start_monitoring(struct devfreq *df) { int ret; struct mrps_stats mrps; prev_ts = ktime_get(); prev_mhz = 0; mrps.high = (df->previous_freq / 1000) - guard_band_mhz; mrps.high /= cycles_per_high_req; ret = hw->start_hwmon(df, &mrps); if (ret) { pr_err("Unable to start HW monitor!\n"); return ret; } devfreq_monitor_start(df); ret = request_threaded_irq(hw->irq, NULL, mon_intr_handler, IRQF_ONESHOT | IRQF_SHARED, "cache_hwmon", df); if (ret) { pr_err("Unable to register interrupt handler!\n"); goto req_irq_fail; } ret = sysfs_create_group(&df->dev.kobj, &dev_attr_group); if (ret) { pr_err("Error creating sys entries!\n"); goto sysfs_fail; } return 0; sysfs_fail: disable_irq(hw->irq); free_irq(hw->irq, df); req_irq_fail: devfreq_monitor_stop(df); hw->stop_hwmon(df); return ret; } static void stop_monitoring(struct devfreq *df) { sysfs_remove_group(&df->dev.kobj, &dev_attr_group); disable_irq(hw->irq); free_irq(hw->irq, df); devfreq_monitor_stop(df); hw->stop_hwmon(df); } static int devfreq_cache_hwmon_ev_handler(struct devfreq *df, unsigned int event, void *data) { int ret; switch (event) { case DEVFREQ_GOV_START: sample_ms = df->profile->polling_ms; sample_ms = max(MIN_MS, sample_ms); sample_ms = min(MAX_MS, sample_ms); df->profile->polling_ms = sample_ms; ret = start_monitoring(df); if (ret) return ret; pr_debug("Enabled Cache HW monitor governor\n"); break; case DEVFREQ_GOV_STOP: stop_monitoring(df); pr_debug("Disabled Cache HW monitor governor\n"); break; case DEVFREQ_GOV_INTERVAL: sample_ms = *(unsigned int *)data; sample_ms = max(MIN_MS, sample_ms); sample_ms = min(MAX_MS, sample_ms); devfreq_interval_update(df, &sample_ms); break; } return 0; } static struct devfreq_governor devfreq_cache_hwmon = { .name = "cache_hwmon", .get_target_freq = devfreq_cache_hwmon_get_freq, .event_handler = devfreq_cache_hwmon_ev_handler, }; int register_cache_hwmon(struct cache_hwmon *hwmon) { int ret; hw = hwmon; ret = devfreq_add_governor(&devfreq_cache_hwmon); if (ret) { pr_err("devfreq governor registration failed\n"); return ret; } return 0; } MODULE_DESCRIPTION("HW monitor based cache freq driver"); MODULE_LICENSE("GPL v2"); drivers/devfreq/governor_cache_hwmon.h 0 → 100644 +38 −0 Original line number Diff line number Diff line /* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (c) 2014, 2016, 2019, The Linux Foundation. All rights reserved. */ #ifndef _GOVERNOR_CACHE_HWMON_H #define _GOVERNOR_CACHE_HWMON_H #include <linux/kernel.h> #include <linux/devfreq.h> struct mrps_stats { unsigned long high; unsigned long med; unsigned long low; unsigned int busy_percent; }; struct cache_hwmon { int (*start_hwmon)(struct devfreq *df, struct mrps_stats *mrps); void (*stop_hwmon)(struct devfreq *df); bool (*is_valid_irq)(struct devfreq *df); unsigned long (*meas_mrps_and_set_irq)(struct devfreq *df, unsigned int tol, unsigned int us, struct mrps_stats *mrps); int irq; }; #ifdef CONFIG_DEVFREQ_GOV_QCOM_CACHE_HWMON int register_cache_hwmon(struct cache_hwmon *hwmon); #else static inline int register_cache_hwmon(struct cache_hwmon *hwmon) { return 0; } #endif #endif /* _GOVERNOR_CACHE_HWMON_H */ Loading
drivers/devfreq/Kconfig +9 −0 Original line number Diff line number Diff line Loading @@ -73,6 +73,15 @@ config DEVFREQ_GOV_PASSIVE through sysfs entries. The passive governor recommends that devfreq device uses the OPP table to get the frequency/voltage. config DEVFREQ_GOV_QCOM_CACHE_HWMON tristate "HW monitor based governor for cache frequency" help HW monitor based governor for cache frequency scaling. This governor sets the cache frequency by using PM counters to monitor the CPU's use of cache. Since this governor uses some of the PM counters it can conflict with existing profiling tools. This governor is unlikely to be useful for other devices. comment "DEVFREQ Drivers" config ARM_EXYNOS_BUS_DEVFREQ Loading
drivers/devfreq/Makefile +1 −0 Original line number Diff line number Diff line Loading @@ -6,6 +6,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE) += governor_performance.o obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o obj-$(CONFIG_DEVFREQ_GOV_QCOM_CACHE_HWMON) += governor_cache_hwmon.o # DEVFREQ Drivers obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o Loading
drivers/devfreq/governor_cache_hwmon.c 0 → 100644 +314 −0 Original line number Diff line number Diff line // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2014, 2019 The Linux Foundation. All rights reserved. */ #define pr_fmt(fmt) "cache-hwmon: " fmt #include <linux/kernel.h> #include <linux/sizes.h> #include <linux/module.h> #include <linux/init.h> #include <linux/io.h> #include <linux/delay.h> #include <linux/ktime.h> #include <linux/time.h> #include <linux/err.h> #include <linux/errno.h> #include <linux/mutex.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/of.h> #include <linux/devfreq.h> #include "governor.h" #include "governor_cache_hwmon.h" #define show_attr(name) \ static ssize_t show_##name(struct device *dev, \ struct device_attribute *attr, char *buf) \ { \ return scnprintf(buf, PAGE_SIZE, "%u\n", name); \ } #define store_attr(name, _min, _max) \ static ssize_t store_##name(struct device *dev, \ struct device_attribute *attr, const char *buf, \ size_t count) \ { \ int ret; \ unsigned int val; \ ret = kstrtoint(buf, 10, &val); \ if (ret) \ return ret; \ val = max(val, _min); \ val = min(val, _max); \ name = val; \ return count; \ } #define gov_attr(__attr, min, max) \ show_attr(__attr) \ store_attr(__attr, (min), (max)) \ static DEVICE_ATTR(__attr, 0644, show_##__attr, store_##__attr) static struct cache_hwmon *hw; static unsigned int cycles_per_low_req; static unsigned int cycles_per_med_req = 20; static unsigned int cycles_per_high_req = 35; static unsigned int min_busy = 100; static unsigned int max_busy = 100; static unsigned int tolerance_mrps = 5; static unsigned int guard_band_mhz = 100; static unsigned int decay_rate = 90; #define MIN_MS 10U #define MAX_MS 500U static unsigned int sample_ms = 50; static unsigned long prev_mhz; static ktime_t prev_ts; static unsigned long measure_mrps_and_set_irq(struct devfreq *df, struct mrps_stats *stat) { ktime_t ts; unsigned int us; /* * Since we are stopping the counters, we don't want this short work * to be interrupted by other tasks and cause the measurements to be * wrong. Not blocking interrupts to avoid affecting interrupt * latency and since they should be short anyway because they run in * atomic context. */ preempt_disable(); ts = ktime_get(); us = ktime_to_us(ktime_sub(ts, prev_ts)); if (!us) us = 1; hw->meas_mrps_and_set_irq(df, tolerance_mrps, us, stat); prev_ts = ts; preempt_enable(); pr_debug("stat H=%3lu, M=%3lu, T=%3lu, b=%3u, f=%4lu, us=%d\n", stat->high, stat->med, stat->high + stat->med, stat->busy_percent, df->previous_freq / 1000, us); return 0; } static void compute_cache_freq(struct mrps_stats *mrps, unsigned long *freq) { unsigned long new_mhz; unsigned int busy; new_mhz = mrps->high * cycles_per_high_req + mrps->med * cycles_per_med_req + mrps->low * cycles_per_low_req; busy = max(min_busy, mrps->busy_percent); busy = min(max_busy, busy); new_mhz *= 100; new_mhz /= busy; if (new_mhz < prev_mhz) { new_mhz = new_mhz * decay_rate + prev_mhz * (100 - decay_rate); new_mhz /= 100; } prev_mhz = new_mhz; new_mhz += guard_band_mhz; *freq = new_mhz * 1000; } #define TOO_SOON_US (1 * USEC_PER_MSEC) static irqreturn_t mon_intr_handler(int irq, void *dev) { struct devfreq *df = dev; ktime_t ts; unsigned int us; int ret; if (!hw->is_valid_irq(df)) return IRQ_NONE; pr_debug("Got interrupt\n"); devfreq_monitor_stop(df); /* * Don't recalc cache freq if the interrupt comes right after a * previous cache freq calculation. This is done for two reasons: * * 1. Sampling the cache request during a very short duration can * result in a very inaccurate measurement due to very short * bursts. * 2. This can only happen if the limit was hit very close to the end * of the previous sample period. Which means the current cache * request estimate is not very off and doesn't need to be * readjusted. */ ts = ktime_get(); us = ktime_to_us(ktime_sub(ts, prev_ts)); if (us > TOO_SOON_US) { mutex_lock(&df->lock); ret = update_devfreq(df); if (ret) pr_err("Unable to update freq on IRQ!\n"); mutex_unlock(&df->lock); } devfreq_monitor_start(df); return IRQ_HANDLED; } static int devfreq_cache_hwmon_get_freq(struct devfreq *df, unsigned long *freq) { struct mrps_stats stat; measure_mrps_and_set_irq(df, &stat); compute_cache_freq(&stat, freq); return 0; } gov_attr(cycles_per_low_req, 1U, 100U); gov_attr(cycles_per_med_req, 1U, 100U); gov_attr(cycles_per_high_req, 1U, 100U); gov_attr(min_busy, 1U, 100U); gov_attr(max_busy, 1U, 100U); gov_attr(tolerance_mrps, 0U, 100U); gov_attr(guard_band_mhz, 0U, 500U); gov_attr(decay_rate, 0U, 100U); static struct attribute *dev_attr[] = { &dev_attr_cycles_per_low_req.attr, &dev_attr_cycles_per_med_req.attr, &dev_attr_cycles_per_high_req.attr, &dev_attr_min_busy.attr, &dev_attr_max_busy.attr, &dev_attr_tolerance_mrps.attr, &dev_attr_guard_band_mhz.attr, &dev_attr_decay_rate.attr, NULL, }; static struct attribute_group dev_attr_group = { .name = "cache_hwmon", .attrs = dev_attr, }; static int start_monitoring(struct devfreq *df) { int ret; struct mrps_stats mrps; prev_ts = ktime_get(); prev_mhz = 0; mrps.high = (df->previous_freq / 1000) - guard_band_mhz; mrps.high /= cycles_per_high_req; ret = hw->start_hwmon(df, &mrps); if (ret) { pr_err("Unable to start HW monitor!\n"); return ret; } devfreq_monitor_start(df); ret = request_threaded_irq(hw->irq, NULL, mon_intr_handler, IRQF_ONESHOT | IRQF_SHARED, "cache_hwmon", df); if (ret) { pr_err("Unable to register interrupt handler!\n"); goto req_irq_fail; } ret = sysfs_create_group(&df->dev.kobj, &dev_attr_group); if (ret) { pr_err("Error creating sys entries!\n"); goto sysfs_fail; } return 0; sysfs_fail: disable_irq(hw->irq); free_irq(hw->irq, df); req_irq_fail: devfreq_monitor_stop(df); hw->stop_hwmon(df); return ret; } static void stop_monitoring(struct devfreq *df) { sysfs_remove_group(&df->dev.kobj, &dev_attr_group); disable_irq(hw->irq); free_irq(hw->irq, df); devfreq_monitor_stop(df); hw->stop_hwmon(df); } static int devfreq_cache_hwmon_ev_handler(struct devfreq *df, unsigned int event, void *data) { int ret; switch (event) { case DEVFREQ_GOV_START: sample_ms = df->profile->polling_ms; sample_ms = max(MIN_MS, sample_ms); sample_ms = min(MAX_MS, sample_ms); df->profile->polling_ms = sample_ms; ret = start_monitoring(df); if (ret) return ret; pr_debug("Enabled Cache HW monitor governor\n"); break; case DEVFREQ_GOV_STOP: stop_monitoring(df); pr_debug("Disabled Cache HW monitor governor\n"); break; case DEVFREQ_GOV_INTERVAL: sample_ms = *(unsigned int *)data; sample_ms = max(MIN_MS, sample_ms); sample_ms = min(MAX_MS, sample_ms); devfreq_interval_update(df, &sample_ms); break; } return 0; } static struct devfreq_governor devfreq_cache_hwmon = { .name = "cache_hwmon", .get_target_freq = devfreq_cache_hwmon_get_freq, .event_handler = devfreq_cache_hwmon_ev_handler, }; int register_cache_hwmon(struct cache_hwmon *hwmon) { int ret; hw = hwmon; ret = devfreq_add_governor(&devfreq_cache_hwmon); if (ret) { pr_err("devfreq governor registration failed\n"); return ret; } return 0; } MODULE_DESCRIPTION("HW monitor based cache freq driver"); MODULE_LICENSE("GPL v2");
drivers/devfreq/governor_cache_hwmon.h 0 → 100644 +38 −0 Original line number Diff line number Diff line /* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (c) 2014, 2016, 2019, The Linux Foundation. All rights reserved. */ #ifndef _GOVERNOR_CACHE_HWMON_H #define _GOVERNOR_CACHE_HWMON_H #include <linux/kernel.h> #include <linux/devfreq.h> struct mrps_stats { unsigned long high; unsigned long med; unsigned long low; unsigned int busy_percent; }; struct cache_hwmon { int (*start_hwmon)(struct devfreq *df, struct mrps_stats *mrps); void (*stop_hwmon)(struct devfreq *df); bool (*is_valid_irq)(struct devfreq *df); unsigned long (*meas_mrps_and_set_irq)(struct devfreq *df, unsigned int tol, unsigned int us, struct mrps_stats *mrps); int irq; }; #ifdef CONFIG_DEVFREQ_GOV_QCOM_CACHE_HWMON int register_cache_hwmon(struct cache_hwmon *hwmon); #else static inline int register_cache_hwmon(struct cache_hwmon *hwmon) { return 0; } #endif #endif /* _GOVERNOR_CACHE_HWMON_H */
