/* This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ /* * main loop scheduler for ArduPilot * Author: Andrew Tridgell, January 2013 * */ #include "AP_Scheduler_config.h" #if AP_SCHEDULER_ENABLED #include "AP_Scheduler.h" #include #include #include #include #include #include #include #include #include #if CONFIG_HAL_BOARD == HAL_BOARD_SITL #include #endif #include #if APM_BUILD_COPTER_OR_HELI || APM_BUILD_TYPE(APM_BUILD_ArduSub) #define SCHEDULER_DEFAULT_LOOP_RATE 400 #else #define SCHEDULER_DEFAULT_LOOP_RATE 50 #endif #define debug(level, fmt, args...) do { if ((level) <= _debug.get()) { hal.console->printf(fmt, ##args); }} while (0) extern const AP_HAL::HAL& hal; const AP_Param::GroupInfo AP_Scheduler::var_info[] = { // @Param: DEBUG // @DisplayName: Scheduler debug level // @Description: Set to non-zero to enable scheduler debug messages. When set to show "Slips" the scheduler will display a message whenever a scheduled task is delayed due to too much CPU load. When set to ShowOverruns the scheduled will display a message whenever a task takes longer than the limit promised in the task table. // @Values: 0:Disabled,2:ShowSlips,3:ShowOverruns // @User: Advanced AP_GROUPINFO("DEBUG", 0, AP_Scheduler, _debug, 0), // @Param: LOOP_RATE // @DisplayName: Scheduling main loop rate // @Description: This controls the rate of the main control loop in Hz. This should only be changed by developers. This only takes effect on restart. Values over 400 are considered highly experimental. // @Values: 50:50Hz,100:100Hz,200:200Hz,250:250Hz,300:300Hz,400:400Hz // @RebootRequired: True // @User: Advanced AP_GROUPINFO("LOOP_RATE", 1, AP_Scheduler, _loop_rate_hz, SCHEDULER_DEFAULT_LOOP_RATE), // @Param: OPTIONS // @DisplayName: Scheduling options // @Description: This controls optional aspects of the scheduler. // @Bitmask: 0:Enable per-task perf info // @User: Advanced AP_GROUPINFO("OPTIONS", 2, AP_Scheduler, _options, 0), AP_GROUPEND }; // constructor AP_Scheduler::AP_Scheduler() { if (_singleton) { #if CONFIG_HAL_BOARD == HAL_BOARD_SITL AP_HAL::panic("Too many schedulers"); #endif return; } _singleton = this; AP_Param::setup_object_defaults(this, var_info); } /* * Get the AP_Scheduler singleton */ AP_Scheduler *AP_Scheduler::_singleton; AP_Scheduler *AP_Scheduler::get_singleton() { return _singleton; } // initialise the scheduler void AP_Scheduler::init(const AP_Scheduler::Task *tasks, uint8_t num_tasks, uint32_t log_performance_bit) { // grab the semaphore before we start anything _rsem.take_blocking(); // only allow 50 to 2000 Hz if (_loop_rate_hz < 50) { _loop_rate_hz.set(50); } else if (_loop_rate_hz > 2000) { _loop_rate_hz.set(2000); } _last_loop_time_s = 1.0 / _loop_rate_hz; _vehicle_tasks = tasks; _num_vehicle_tasks = num_tasks; #if AP_VEHICLE_ENABLED AP_Vehicle* vehicle = AP::vehicle(); if (vehicle != nullptr) { vehicle->get_common_scheduler_tasks(_common_tasks, _num_common_tasks); } #endif _num_tasks = _num_vehicle_tasks + _num_common_tasks; _last_run = NEW_NOTHROW uint16_t[_num_tasks]; _tick_counter = 0; // setup initial performance counters perf_info.set_loop_rate(get_loop_rate_hz()); perf_info.reset(); if (_options & uint8_t(Options::RECORD_TASK_INFO)) { perf_info.allocate_task_info(_num_tasks); } _log_performance_bit = log_performance_bit; // sanity check the task lists to ensure the priorities are // never decrease uint8_t old = 0; for (uint8_t i=0; i<_num_common_tasks; i++) { if (_common_tasks[i].priority < old){ INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control); break; } old = _common_tasks[i].priority; } old = 0; for (uint8_t i=0; i<_num_vehicle_tasks; i++) { if (_vehicle_tasks[i].priority < old) { INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control); break; } old = _vehicle_tasks[i].priority; } } // one tick has passed void AP_Scheduler::tick(void) { _tick_counter++; _tick_counter32++; } #if CONFIG_HAL_BOARD == HAL_BOARD_SITL /* fill stack with NaN so we can catch use of uninitialised stack variables in SITL */ static void fill_nanf_stack(void) { float v[1024]; fill_nanf(v, ARRAY_SIZE(v)); } #endif /* run one tick this will run as many scheduler tasks as we can in the specified time */ void AP_Scheduler::run(uint32_t time_available) { uint32_t run_started_usec = AP_HAL::micros(); uint32_t now = run_started_usec; uint8_t vehicle_tasks_offset = 0; uint8_t common_tasks_offset = 0; for (uint8_t i=0; i<_num_tasks; i++) { // determine which of the common task / vehicle task to run bool run_vehicle_task = false; if (vehicle_tasks_offset < _num_vehicle_tasks && common_tasks_offset < _num_common_tasks) { // still have entries on both lists; compare the // priorities. In case of a tie the vehicle-specific // entry wins. const Task &vehicle_task = _vehicle_tasks[vehicle_tasks_offset]; const Task &common_task = _common_tasks[common_tasks_offset]; if (vehicle_task.priority <= common_task.priority) { run_vehicle_task = true; } } else if (vehicle_tasks_offset < _num_vehicle_tasks) { // out of common tasks to run run_vehicle_task = true; } else if (common_tasks_offset < _num_common_tasks) { // out of vehicle tasks to run run_vehicle_task = false; } else { // this is an error; the outside loop should have terminated INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control); break; } const AP_Scheduler::Task &task = run_vehicle_task ? _vehicle_tasks[vehicle_tasks_offset] : _common_tasks[common_tasks_offset]; if (run_vehicle_task) { vehicle_tasks_offset++; } else { common_tasks_offset++; } if (task.priority > MAX_FAST_TASK_PRIORITIES) { const uint16_t dt = _tick_counter - _last_run[i]; // we allow 0 to mean loop rate uint32_t interval_ticks = (is_zero(task.rate_hz) ? 1 : _loop_rate_hz / task.rate_hz); if (interval_ticks < 1) { interval_ticks = 1; } if (dt < interval_ticks) { // this task is not yet scheduled to run again continue; } // this task is due to run. Do we have enough time to run it? _task_time_allowed = task.max_time_micros; if (dt >= interval_ticks*2) { perf_info.task_slipped(i); } if (dt >= interval_ticks*max_task_slowdown) { // we are going beyond the maximum slowdown factor for a // task. This will trigger increasing the time budget task_not_achieved++; } if (_task_time_allowed > time_available) { // not enough time to run this task. Continue loop - // maybe another task will fit into time remaining continue; } } else { _task_time_allowed = get_loop_period_us(); } // run it _task_time_started = now; hal.util->persistent_data.scheduler_task = i; #if CONFIG_HAL_BOARD == HAL_BOARD_SITL fill_nanf_stack(); #endif task.function(); hal.util->persistent_data.scheduler_task = -1; // record the tick counter when we ran. This drives // when we next run the event _last_run[i] = _tick_counter; // work out how long the event actually took now = AP_HAL::micros(); uint32_t time_taken = now - _task_time_started; bool overrun = false; if (time_taken > _task_time_allowed) { overrun = true; // the event overran! debug(3, "Scheduler overrun task[%u-%s] (%u/%u)\n", (unsigned)i, task.name, (unsigned)time_taken, (unsigned)_task_time_allowed); } perf_info.update_task_info(i, time_taken, overrun); if (time_taken >= time_available) { /* we are out of time, but we need to keep walking the task table in case there is another fast loop task after this task, plus we need to update the accouting so we can work out if we need to allocate extra time for the loop (lower the loop rate) Just set time_available to zero, which means we will only run fast tasks after this one */ time_available = 0; } else { time_available -= time_taken; } } // update number of spare microseconds _spare_micros += time_available; _spare_ticks++; if (_spare_ticks == 32) { _spare_ticks /= 2; _spare_micros /= 2; } } /* return number of micros until the current task reaches its deadline */ uint16_t AP_Scheduler::time_available_usec(void) const { uint32_t dt = AP_HAL::micros() - _task_time_started; if (dt > _task_time_allowed) { return 0; } return _task_time_allowed - dt; } /* calculate load average as a number from 0 to 1 */ float AP_Scheduler::load_average() { // return 1 if filtered main loop rate is 5% below the configured rate if (get_filtered_loop_rate_hz() < get_loop_rate_hz() * 0.95) { return 1.0; } if (_spare_ticks == 0) { return 0.0f; } const uint32_t loop_us = get_loop_period_us(); const uint32_t used_time = loop_us - (_spare_micros/_spare_ticks); return constrain_float(used_time / (float)loop_us, 0, 1); } void AP_Scheduler::loop() { // wait for an INS sample hal.util->persistent_data.scheduler_task = -3; _rsem.give(); AP::ins().wait_for_sample(); _rsem.take_blocking(); hal.util->persistent_data.scheduler_task = -1; const uint32_t sample_time_us = AP_HAL::micros(); if (_loop_timer_start_us == 0) { _loop_timer_start_us = sample_time_us; _last_loop_time_s = get_loop_period_s(); } else { _last_loop_time_s = (sample_time_us - _loop_timer_start_us) * 1.0e-6; } #if CONFIG_HAL_BOARD == HAL_BOARD_SITL { /* for testing low CPU conditions we can add an optional delay in SITL */ auto *sitl = AP::sitl(); uint32_t loop_delay_us = sitl? sitl->loop_delay.get() : 1000U; hal.scheduler->delay_microseconds(loop_delay_us); } #endif // tell the scheduler one tick has passed tick(); // run all the tasks that are due to run. Note that we only // have to call this once per loop, as the tasks are scheduled // in multiples of the main loop tick. So if they don't run on // the first call to the scheduler they won't run on a later // call until scheduler.tick() is called again const uint32_t loop_us = get_loop_period_us(); uint32_t now = AP_HAL::micros(); uint32_t time_available = 0; const uint32_t loop_tick_us = now - sample_time_us; if (loop_tick_us < loop_us) { // get remaining time available for this loop time_available = loop_us - loop_tick_us; } // add in extra loop time determined by not achieving scheduler tasks time_available += extra_loop_us; // run the tasks run(time_available); #if CONFIG_HAL_BOARD == HAL_BOARD_SITL // move result of AP_HAL::micros() forward: hal.scheduler->delay_microseconds(1); #endif if (task_not_achieved > 0) { // add some extra time to the budget extra_loop_us = MIN(extra_loop_us+100U, 5000U); task_not_achieved = 0; task_all_achieved = 0; } else if (extra_loop_us > 0) { task_all_achieved++; if (task_all_achieved > 50) { // we have gone through 50 loops without a task taking too // long. CPU pressure has eased, so drop the extra time we're // giving each loop task_all_achieved = 0; // we are achieving all tasks, slowly lower the extra loop time extra_loop_us = MAX(0U, extra_loop_us-50U); } } // check loop time perf_info.check_loop_time(sample_time_us - _loop_timer_start_us); _loop_timer_start_us = sample_time_us; #if AP_SIM_ENABLED && CONFIG_HAL_BOARD != HAL_BOARD_SITL hal.simstate->update(); #endif } #if HAL_LOGGING_ENABLED void AP_Scheduler::update_logging() { if (debug_flags()) { perf_info.update_logging(); } if (_log_performance_bit != (uint32_t)-1 && AP::logger().should_log(_log_performance_bit)) { Log_Write_Performance(); } perf_info.set_loop_rate(get_loop_rate_hz()); perf_info.reset(); // dynamically update the per-task perf counter if (!(_options & uint8_t(Options::RECORD_TASK_INFO)) && perf_info.has_task_info()) { perf_info.free_task_info(); } else if ((_options & uint8_t(Options::RECORD_TASK_INFO)) && !perf_info.has_task_info()) { perf_info.allocate_task_info(_num_tasks); } } // Write a performance monitoring packet void AP_Scheduler::Log_Write_Performance() { const AP_HAL::Util::PersistentData &pd = hal.util->persistent_data; struct log_Performance pkt = { LOG_PACKET_HEADER_INIT(LOG_PERFORMANCE_MSG), time_us : AP_HAL::micros64(), loop_rate : (uint16_t)(get_filtered_loop_rate_hz() + 0.5f), num_long_running : perf_info.get_num_long_running(), num_loops : perf_info.get_num_loops(), max_time : perf_info.get_max_time(), mem_avail : hal.util->available_memory(), load : (uint16_t)(load_average() * 1000), internal_error_last_line : AP::internalerror().last_error_line(), internal_errors : AP::internalerror().errors(), internal_error_count : AP::internalerror().count(), spi_count : pd.spi_count, i2c_count : pd.i2c_count, i2c_isr_count : pd.i2c_isr_count, extra_loop_us : extra_loop_us, }; AP::logger().WriteCriticalBlock(&pkt, sizeof(pkt)); } #endif // HAL_LOGGING_ENABLED // display task statistics as text buffer for @SYS/tasks.txt void AP_Scheduler::task_info(ExpandingString &str) { // a header to allow for machine parsers to determine format str.printf("TasksV2\n"); // dynamically enable statistics collection if (!(_options & uint8_t(Options::RECORD_TASK_INFO))) { _options.set(_options | uint8_t(Options::RECORD_TASK_INFO)); return; } if (perf_info.get_task_info(0) == nullptr) { return; } // baseline the total time taken by all tasks float total_time = 1.0f; for (uint8_t i = 0; i < _num_tasks + 1; i++) { const AP::PerfInfo::TaskInfo* ti = perf_info.get_task_info(i); if (ti != nullptr && ti->tick_count > 0) { total_time += ti->elapsed_time_us; } } uint8_t vehicle_tasks_offset = 0; uint8_t common_tasks_offset = 0; for (uint8_t i = 0; i < _num_tasks; i++) { const AP::PerfInfo::TaskInfo* ti = perf_info.get_task_info(i); const char *task_name; // determine which of the common task / vehicle task to run bool run_vehicle_task = false; if (vehicle_tasks_offset < _num_vehicle_tasks && common_tasks_offset < _num_common_tasks) { // still have entries on both lists; compare the // priorities. In case of a tie the vehicle-specific // entry wins. const Task &vehicle_task = _vehicle_tasks[vehicle_tasks_offset]; const Task &common_task = _common_tasks[common_tasks_offset]; if (vehicle_task.priority <= common_task.priority) { run_vehicle_task = true; } } else if (vehicle_tasks_offset < _num_vehicle_tasks) { // out of common tasks to run run_vehicle_task = true; } else if (common_tasks_offset < _num_common_tasks) { // out of vehicle tasks to run run_vehicle_task = false; } else { // this is an error; the outside loop should have terminated INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control); return; } if (run_vehicle_task) { task_name = _vehicle_tasks[vehicle_tasks_offset++].name; } else { task_name = _common_tasks[common_tasks_offset++].name; } ti->print(task_name, total_time, str); } } namespace AP { AP_Scheduler &scheduler() { return *AP_Scheduler::get_singleton(); } }; #endif // AP_SCHEDULER_ENABLED