bizhang_-obav/src/modules/load_mon/load_mon.cpp

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/**
 * @file load_mon.cpp
 *
 * @author Jonathan Challinger <jonathan@3drobotics.com>
 * @author Julian Oes <julian@oes.ch
 * @author Andreas Antener <andreas@uaventure.com>
 */

#include <drivers/drv_hrt.h>
#include <lib/perf/perf_counter.h>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/defines.h>
#include <px4_platform_common/module.h>
#include <px4_platform_common/module_params.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <systemlib/cpuload.h>
#include <uORB/Publication.hpp>
#include <uORB/topics/cpuload.h>
#include <uORB/topics/task_stack_info.h>

#if defined(__PX4_NUTTX) && !defined(CONFIG_SCHED_INSTRUMENTATION)
#  error load_mon support requires CONFIG_SCHED_INSTRUMENTATION
#endif

// if free stack space falls below this, print a warning
#if defined(CONFIG_ARMV7M_STACKCHECK)
static constexpr unsigned STACK_LOW_WARNING_THRESHOLD = 100;
#else
static constexpr unsigned STACK_LOW_WARNING_THRESHOLD = 300;
#endif

static constexpr unsigned FDS_LOW_WARNING_THRESHOLD = 2; ///< if free file descriptors fall below this, print a warning

using namespace time_literals;

namespace load_mon
{

class LoadMon : public ModuleBase<LoadMon>, public ModuleParams, public px4::ScheduledWorkItem
{
public:
	LoadMon();
	~LoadMon() override;

	static int task_spawn(int argc, char *argv[]);

	/** @see ModuleBase */
	static int custom_command(int argc, char *argv[])
	{
		return print_usage("unknown command");
	}

	/** @see ModuleBase */
	static int print_usage(const char *reason = nullptr);

	void start();

private:
	/** Do a compute and schedule the next cycle. */
	void Run() override;

	/** Do a calculation of the CPU load and publish it. */
	void cpuload();

	/* Calculate stack usage */
	void stack_usage();

	int _stack_task_index{0};
	uORB::PublicationQueued<task_stack_info_s> _task_stack_info_pub{ORB_ID(task_stack_info)};

	DEFINE_PARAMETERS(
		(ParamBool<px4::params::SYS_STCK_EN>) _param_sys_stck_en
	)

	uORB::Publication<cpuload_s>  _cpuload_pub{ORB_ID(cpuload)};

	hrt_abstime _last_idle_time{0};
	hrt_abstime _last_idle_time_sample{0};

	perf_counter_t _cycle_perf{perf_alloc(PC_ELAPSED, MODULE_NAME": cycle")};
};

LoadMon::LoadMon() :
	ModuleParams(nullptr),
	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::lp_default)
{
}

LoadMon::~LoadMon()
{
	ScheduleClear();

	perf_free(_cycle_perf);
}

int LoadMon::task_spawn(int argc, char *argv[])
{
	LoadMon *obj = new LoadMon();

	if (!obj) {
		PX4_ERR("alloc failed");
		return -1;
	}

	_object.store(obj);
	_task_id = task_id_is_work_queue;

	/* Schedule a cycle to start things. */
	obj->start();

	return 0;
}

void LoadMon::start()
{
	ScheduleOnInterval(300_ms);
}

void LoadMon::Run()
{
	perf_begin(_cycle_perf);

	cpuload();

	if (_param_sys_stck_en.get()) {
		stack_usage();
	}

	if (should_exit()) {
		ScheduleClear();
		exit_and_cleanup();
	}

	perf_end(_cycle_perf);
}

void LoadMon::cpuload()
{
	if (_last_idle_time == 0) {
		// Just get the time in the first iteration */
		_last_idle_time = system_load.tasks[0].total_runtime;
		_last_idle_time_sample = hrt_absolute_time();
		return;
	}

	irqstate_t irqstate = enter_critical_section();
	const hrt_abstime now = hrt_absolute_time();
	const hrt_abstime total_runtime = system_load.tasks[0].total_runtime;
	leave_critical_section(irqstate);

	// compute system load
	const float interval = now - _last_idle_time_sample;
	const float interval_idletime = total_runtime - _last_idle_time;

	// get ram usage
	struct mallinfo mem = mallinfo();
	float ram_usage = (float)mem.uordblks / mem.arena;

	cpuload_s cpuload{};
	cpuload.load = 1.f - interval_idletime / interval;
	cpuload.ram_usage = ram_usage;
	cpuload.timestamp = hrt_absolute_time();

	_cpuload_pub.publish(cpuload);

	// store for next iteration
	_last_idle_time = total_runtime;
	_last_idle_time_sample = now;
}

void LoadMon::stack_usage()
{
	unsigned stack_free = 0;
	unsigned fds_free = FDS_LOW_WARNING_THRESHOLD + 1;

	bool checked_task = false;

	task_stack_info_s task_stack_info{};
	static_assert(sizeof(task_stack_info.task_name) == CONFIG_TASK_NAME_SIZE,
		      "task_stack_info.task_name must match NuttX CONFIG_TASK_NAME_SIZE");

	sched_lock();

	if (system_load.tasks[_stack_task_index].valid && (system_load.tasks[_stack_task_index].tcb->pid > 0)) {

		stack_free = up_check_tcbstack_remain(system_load.tasks[_stack_task_index].tcb);

		strncpy((char *)task_stack_info.task_name, system_load.tasks[_stack_task_index].tcb->name, CONFIG_TASK_NAME_SIZE - 1);
		task_stack_info.task_name[CONFIG_TASK_NAME_SIZE - 1] = '\0';

		checked_task = true;

#if CONFIG_NFILE_DESCRIPTORS > 0
		FAR struct task_group_s *group = system_load.tasks[_stack_task_index].tcb->group;

		unsigned tcb_num_used_fds = 0;

		if (group) {
			for (int fd_index = 0; fd_index < CONFIG_NFILE_DESCRIPTORS; ++fd_index) {
				if (group->tg_filelist.fl_files[fd_index].f_inode) {
					++tcb_num_used_fds;
				}
			}

			fds_free = CONFIG_NFILE_DESCRIPTORS - tcb_num_used_fds;
		}

#endif // CONFIG_NFILE_DESCRIPTORS
	}

	sched_unlock();

	if (checked_task) {
		task_stack_info.stack_free = stack_free;
		task_stack_info.timestamp = hrt_absolute_time();

		_task_stack_info_pub.publish(task_stack_info);

		// Found task low on stack, report and exit. Continue here in next cycle.
		if (stack_free < STACK_LOW_WARNING_THRESHOLD) {
			PX4_WARN("%s low on stack! (%i bytes left)", task_stack_info.task_name, stack_free);
		}

		// Found task low on file descriptors, report and exit. Continue here in next cycle.
		if (fds_free < FDS_LOW_WARNING_THRESHOLD) {
			PX4_WARN("%s low on FDs! (%i FDs left)", task_stack_info.task_name, fds_free);
		}
	}

	// Continue after last checked task next cycle
	_stack_task_index = (_stack_task_index + 1) % CONFIG_MAX_TASKS;
}

int LoadMon::print_usage(const char *reason)
{
	if (reason) {
		PX4_ERR("%s\n", reason);
	}

	PRINT_MODULE_DESCRIPTION(
		R"DESCR_STR(
### Description
Background process running periodically with 1 Hz on the low priority work queue to calculate the CPU load and RAM
usage and publish the `cpuload` topic.

On NuttX it also checks the stack usage of each process and if it falls below 300 bytes, a warning is output,
which will also appear in the log file.
)DESCR_STR");

	PRINT_MODULE_USAGE_NAME("load_mon", "system");
	PRINT_MODULE_USAGE_COMMAND_DESCR("start", "Start the background task");
	PRINT_MODULE_USAGE_DEFAULT_COMMANDS();
	return 0;
}

extern "C" __EXPORT int load_mon_main(int argc, char *argv[])
{
	return LoadMon::main(argc, argv);
}

} // namespace load_mon