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/*
* Copyright (c) 2006-2022, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2022-11-21 GuEe-GUI first version
*/
#include <rthw.h>
#include <rtthread.h>
#include <rtdevice.h>
#define DBG_TAG "dvfs.governor.conservative"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
/* Default parameters (Linux-like) */
#define CONSERVATIVE_DEFAULT_SAMPLING_RATE_MS 1000
#define CONSERVATIVE_DEFAULT_UP_THRESHOLD 80
#define CONSERVATIVE_DEFAULT_DOWN_DIFFERENTIAL 20
#define CONSERVATIVE_DEFAULT_FREQ_STEP 5
#define CONSERVATIVE_DEFAULT_SAMPLING_DOWN_FACTOR 1
struct governor_conservative_data
{
struct rt_work monitor_work;
rt_bool_t running;
};
static rt_bool_t governor_conservative_active(struct rt_dvfs_scaling *dvfs)
{
struct governor_conservative_data *data;
if (!dvfs || !dvfs->gov ||
dvfs->gov->type != RT_DVFS_GOVERNOR_TYPE_CONSERVATIVE)
{
return RT_FALSE;
}
data = dvfs->gov_data;
return data && data->running;
}
static void governor_conservative_monitor(struct rt_work *work, void *work_data)
{
struct rt_dvfs_scaling *dvfs = (struct rt_dvfs_scaling *)work_data;
struct governor_conservative_data *data;
struct rt_dvfs_opp *opp;
rt_ubase_t target_freq;
rt_uint32_t load;
if (!governor_conservative_active(dvfs))
{
return;
}
data = dvfs->gov_data;
/* Update CPU load statistics */
rt_dvfs_load_update(dvfs);
load = rt_dvfs_cpu_load_get(&dvfs->cpu_load);
target_freq = dvfs->cur_freq;
/* Determine target frequency based on load */
if (load >= dvfs->gov_params.up_threshold)
{
/* High load: step up frequency */
rt_ubase_t step_freq = (dvfs->max_freq * dvfs->gov_params.freq_step) / 100;
target_freq = dvfs->cur_freq + step_freq;
/* Find ceil OPP */
opp = rt_dvfs_scaling_find_ceil_opp(dvfs, target_freq);
if (opp && opp->available && opp->freq > dvfs->cur_freq)
{
target_freq = opp->freq;
}
else
{
target_freq = dvfs->max_freq;
}
LOG_D("%s: load=%u%% >= up_threshold=%u%%, step up to %lu Hz",
rt_dm_dev_get_name(dvfs->dev), load,
dvfs->gov_params.up_threshold, target_freq);
}
else if (load < dvfs->gov_params.down_differential)
{
/* Low load: step down frequency */
rt_ubase_t step_freq = (dvfs->max_freq * dvfs->gov_params.freq_step) / 100;
target_freq = (dvfs->cur_freq > step_freq) ? (dvfs->cur_freq - step_freq) : dvfs->min_freq;
/* Find floor OPP */
opp = rt_dvfs_scaling_find_floor_opp(dvfs, target_freq);
if (opp && opp->available && opp->freq < dvfs->cur_freq)
{
target_freq = opp->freq;
}
else
{
target_freq = dvfs->min_freq;
}
LOG_D("%s: load=%u%% < down_threshold=%u%%, step down to %lu Hz",
rt_dm_dev_get_name(dvfs->dev), load,
dvfs->gov_params.down_differential, target_freq);
}
else
{
/* Medium load: keep current frequency */
LOG_D("%s: load=%u%% in range, keep freq %lu Hz",
rt_dm_dev_get_name(dvfs->dev), load, dvfs->cur_freq);
}
/* Set target frequency if different */
if (target_freq != dvfs->cur_freq && governor_conservative_active(dvfs))
{
rt_err_t err = rt_dvfs_scaling_set_frequency(dvfs, target_freq);
if (err)
{
LOG_W("%s: set frequency %lu failed: %s",
rt_dm_dev_get_name(dvfs->dev), target_freq, rt_strerror(err));
}
}
/* Reschedule monitoring work */
if (governor_conservative_active(dvfs))
{
rt_work_submit(&data->monitor_work,
rt_tick_from_millisecond(dvfs->gov_params.sampling_rate_ms));
}
}
static rt_err_t governor_conservative_start(struct rt_dvfs_scaling *dvfs)
{
struct governor_conservative_data *data;
if (!dvfs)
{
return -RT_EINVAL;
}
/* Initialize default parameters if not set */
if (dvfs->gov_params.sampling_rate_ms == 0)
{
dvfs->gov_params.sampling_rate_ms = CONSERVATIVE_DEFAULT_SAMPLING_RATE_MS;
}
if (dvfs->gov_params.up_threshold == 0)
{
dvfs->gov_params.up_threshold = CONSERVATIVE_DEFAULT_UP_THRESHOLD;
}
if (dvfs->gov_params.down_differential == 0)
{
dvfs->gov_params.down_differential = CONSERVATIVE_DEFAULT_DOWN_DIFFERENTIAL;
}
if (dvfs->gov_params.freq_step == 0)
{
dvfs->gov_params.freq_step = CONSERVATIVE_DEFAULT_FREQ_STEP;
}
if (dvfs->gov_params.sampling_down_factor == 0)
{
dvfs->gov_params.sampling_down_factor = CONSERVATIVE_DEFAULT_SAMPLING_DOWN_FACTOR;
}
/* Allocate governor data */
data = rt_calloc(1, sizeof(*data));
if (!data)
{
LOG_E("%s: no memory for conservative data", rt_dm_dev_get_name(dvfs->dev));
return -RT_ENOMEM;
}
dvfs->gov_data = data;
data->running = RT_TRUE;
/* Initialize CPU load */
dvfs->cpu_load.last_update = rt_tick_get();
dvfs->cpu_load.total_tick = 0;
dvfs->cpu_load.idle_tick = 0;
dvfs->cpu_load.load_percentage = 0;
/* Initialize monitoring work */
rt_work_init(&data->monitor_work, governor_conservative_monitor, dvfs);
/* Submit first monitoring work */
rt_work_submit(&data->monitor_work,
rt_tick_from_millisecond(dvfs->gov_params.sampling_rate_ms));
LOG_D("%s: conservative governor started (sampling=%ums, up_threshold=%u%%, down_threshold=%u%%, freq_step=%u%%)",
rt_dm_dev_get_name(dvfs->dev),
dvfs->gov_params.sampling_rate_ms,
dvfs->gov_params.up_threshold,
dvfs->gov_params.down_differential,
dvfs->gov_params.freq_step);
return RT_EOK;
}
static rt_err_t governor_conservative_stop(struct rt_dvfs_scaling *dvfs)
{
struct governor_conservative_data *data;
if (!dvfs || !dvfs->gov)
{
return -RT_EINVAL;
}
data = dvfs->gov_data;
if (data)
{
data->running = RT_FALSE;
rt_work_cancel(&data->monitor_work);
/* Wait for work to complete */
rt_thread_mdelay(10);
rt_free(data);
dvfs->gov_data = RT_NULL;
}
LOG_D("%s: conservative governor stopped", rt_dm_dev_get_name(dvfs->dev));
return RT_EOK;
}
static rt_err_t governor_conservative_suspend(struct rt_dvfs_scaling *dvfs)
{
struct governor_conservative_data *data;
if (!dvfs || !dvfs->gov)
{
return -RT_EINVAL;
}
/* Stop monitoring */
data = dvfs->gov_data;
if (data)
{
data->running = RT_FALSE;
rt_work_cancel(&data->monitor_work);
}
return RT_EOK;
}
static rt_err_t governor_conservative_resume(struct rt_dvfs_scaling *dvfs)
{
struct governor_conservative_data *data;
if (!dvfs || !dvfs->gov)
{
return -RT_EINVAL;
}
/* Resume monitoring */
data = dvfs->gov_data;
if (data)
{
/* Reset CPU load statistics */
dvfs->cpu_load.last_update = rt_tick_get();
dvfs->cpu_load.total_tick = 0;
dvfs->cpu_load.idle_tick = 0;
data->running = RT_TRUE;
rt_work_submit(&data->monitor_work,
rt_tick_from_millisecond(dvfs->gov_params.sampling_rate_ms));
}
return RT_EOK;
}
static rt_err_t governor_conservative_set_interval(struct rt_dvfs_scaling *dvfs, rt_uint32_t interval_ms)
{
if (!dvfs)
{
return -RT_EINVAL;
}
/* Minimum sampling interval: 10ms */
if (interval_ms < 10)
{
interval_ms = 10;
}
dvfs->gov_params.sampling_rate_ms = interval_ms;
LOG_D("%s: conservative sampling interval set to %ums",
rt_dm_dev_get_name(dvfs->dev), interval_ms);
return RT_EOK;
}
static rt_err_t governor_conservative_set_frequency(struct rt_dvfs_scaling *dvfs, rt_ubase_t *out_freq)
{
if (!dvfs || !out_freq)
{
return -RT_EINVAL;
}
/* Conservative sets frequency based on load, not requested frequency */
/* Return current frequency */
*out_freq = dvfs->cur_freq;
return RT_EOK;
}
static struct rt_dvfs_governor governor_conservative =
{
.name = "conservative",
.type = RT_DVFS_GOVERNOR_TYPE_CONSERVATIVE,
.start = governor_conservative_start,
.stop = governor_conservative_stop,
.suspend = governor_conservative_suspend,
.resume = governor_conservative_resume,
.set_interval = governor_conservative_set_interval,
.set_frequency = governor_conservative_set_frequency,
};
static int governor_conservative_init(void)
{
rt_dvfs_governor_register(&governor_conservative);
return 0;
}
INIT_CORE_EXPORT(governor_conservative_init);
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