/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2010-2014  Université de Bordeaux 1
 * Copyright (C) 2010  Mehdi Juhoor <mjuhoor@gmail.com>
 * Copyright (C) 2010-2013  Centre National de la Recherche Scientifique
 * Copyright (C) 2011  Télécom-SudParis
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU 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 Lesser General Public License in COPYING.LGPL for more details.
 */

#include <common/config.h>

#include <math.h>
#include <starpu.h>
#include <starpu_profiling.h>
#include <drivers/driver_common/driver_common.h>
#include <common/utils.h>
#include <core/debug.h>
#include <core/workers.h>
#include "driver_cpu.h"
#include <core/sched_policy.h>
#include <datawizard/memory_manager.h>
#include <datawizard/malloc.h>

#ifdef STARPU_HAVE_HWLOC
#include <hwloc.h>
#ifndef HWLOC_API_VERSION
#define HWLOC_OBJ_PU HWLOC_OBJ_PROC
#endif
#endif

#ifdef STARPU_HAVE_WINDOWS
#include <windows.h>
#endif

#ifdef STARPU_SIMGRID
#include <core/simgrid.h>
#endif

#ifdef STARPU_SIMGRID
void
_starpu_cpu_discover_devices(struct _starpu_machine_config *config)
{
	config->topology.nhwcpus = _starpu_simgrid_get_nbhosts("CPU");
}
#elif defined(STARPU_HAVE_HWLOC)
void
_starpu_cpu_discover_devices(struct _starpu_machine_config *config)
{
	/* Discover the CPUs relying on the hwloc interface and fills CONFIG
	 * accordingly. */

	struct _starpu_machine_topology *topology = &config->topology;

	config->cpu_depth = hwloc_get_type_depth (topology->hwtopology,
						  HWLOC_OBJ_CORE);

	/* Would be very odd */
	STARPU_ASSERT(config->cpu_depth != HWLOC_TYPE_DEPTH_MULTIPLE);

	if (config->cpu_depth == HWLOC_TYPE_DEPTH_UNKNOWN) {
		/* unknown, using logical procesors as fallback */
		_STARPU_DISP("Warning: The OS did not report CPU cores. Assuming there is only one hardware thread per core.\n");
		config->cpu_depth = hwloc_get_type_depth(topology->hwtopology,
							 HWLOC_OBJ_PU);
	}

	topology->nhwcpus = hwloc_get_nbobjs_by_depth (topology->hwtopology,
						       config->cpu_depth);
}

#elif defined(HAVE_SYSCONF)
void
_starpu_cpu_discover_devices(struct _starpu_machine_config *config)
{
	/* Discover the CPUs relying on the sysconf(3) function and fills
	 * CONFIG accordingly. */

	config->topology.nhwcpus = sysconf(_SC_NPROCESSORS_ONLN);
}

#elif defined(__MINGW32__) || defined(__CYGWIN__)
void
_starpu_cpu_discover_devices(struct _starpu_machine_config *config)
{
	/* Discover the CPUs on Cygwin and MinGW systems. */

	SYSTEM_INFO sysinfo;
	GetSystemInfo(&sysinfo);
	config->topology.nhwcpus = sysinfo.dwNumberOfProcessors;
}
#else
#warning no way to know number of cores, assuming 1
void
_starpu_cpu_discover_devices(struct _starpu_machine_config *config)
{
	config->topology.nhwcpus = 1;
}
#endif


/* Actually launch the job on a cpu worker.
 * Handle binding CPUs on cores.
 * In the case of a combined worker WORKER_TASK != J->TASK */

static int execute_job_on_cpu(struct _starpu_job *j, struct starpu_task *worker_task, struct _starpu_worker *cpu_args, int rank, enum starpu_perfmodel_archtype perf_arch)
{
	int ret;
	int is_parallel_task = (j->task_size > 1);
	int profiling = starpu_profiling_status_get();
	struct timespec codelet_start, codelet_end;

	struct starpu_task *task = j->task;
	struct starpu_codelet *cl = task->cl;

	STARPU_ASSERT(cl);

	if (rank == 0)
	{
		ret = _starpu_fetch_task_input(j, 0);
		if (ret != 0)
		{
			/* there was not enough memory so the codelet cannot be executed right now ... */
			/* push the codelet back and try another one ... */
			return -EAGAIN;
		}
	}

	if (is_parallel_task)
	{
		STARPU_PTHREAD_BARRIER_WAIT(&j->before_work_barrier);

		/* In the case of a combined worker, the scheduler needs to know
		 * when each actual worker begins the execution */
		_starpu_sched_pre_exec_hook(worker_task);
	}

	/* Give profiling variable */
	_starpu_driver_start_job(cpu_args, j, &codelet_start, rank, profiling);

	/* In case this is a Fork-join parallel task, the worker does not
	 * execute the kernel at all. */
	if ((rank == 0) || (cl->type != STARPU_FORKJOIN))
	{
		_starpu_cl_func_t func = _starpu_task_get_cpu_nth_implementation(cl, j->nimpl);
		if (is_parallel_task && cl->type == STARPU_FORKJOIN)
			/* bind to parallel worker */
			_starpu_bind_thread_on_cpus(cpu_args->config, _starpu_get_combined_worker_struct(j->combined_workerid));
		STARPU_ASSERT_MSG(func, "when STARPU_CPU is defined in 'where', cpu_func or cpu_funcs has to be defined");
		if (starpu_get_env_number("STARPU_DISABLE_KERNELS") <= 0)
		{
#ifdef STARPU_SIMGRID
			_starpu_simgrid_execute_job(j, perf_arch, NAN);
#else
			func(_STARPU_TASK_GET_INTERFACES(task), task->cl_arg);
#endif
		}
		if (is_parallel_task && cl->type == STARPU_FORKJOIN)
			/* rebind to single CPU */
			_starpu_bind_thread_on_cpu(cpu_args->config, cpu_args->bindid);
	}

	_starpu_driver_end_job(cpu_args, j, perf_arch, &codelet_end, rank, profiling);

	if (is_parallel_task)
		STARPU_PTHREAD_BARRIER_WAIT(&j->after_work_barrier);

	if (rank == 0)
	{
		_starpu_driver_update_job_feedback(j, cpu_args,
				perf_arch, &codelet_start, &codelet_end, profiling);
		_starpu_push_task_output(j, 0);
	}

	return 0;
}

static size_t _starpu_cpu_get_global_mem_size(int nodeid, struct _starpu_machine_config *config)
{
	size_t global_mem;
	starpu_ssize_t limit;

	limit = starpu_get_env_number("STARPU_LIMIT_CPU_MEM");
#ifdef STARPU_DEVEL
#  warning TODO: take into account NUMA node and check STARPU_LIMIT_CPU_numanode_MEM
#endif

#if defined(STARPU_HAVE_HWLOC)
        int depth_node;
	struct _starpu_machine_topology *topology = &config->topology;

#if 0
	/* Do not limit ourself to a single NUMA node yet, as we don't have real NUMA support for now */
        depth_node = hwloc_get_type_depth(topology->hwtopology, HWLOC_OBJ_NODE);

	if (depth_node == HWLOC_TYPE_DEPTH_UNKNOWN)
	     global_mem = hwloc_get_root_obj(topology->hwtopology)->memory.total_memory;
	else
	     global_mem = hwloc_get_obj_by_depth(topology->hwtopology, depth_node, nodeid)->memory.local_memory;
#else
	global_mem = hwloc_get_root_obj(topology->hwtopology)->memory.total_memory;
#endif

#else /* STARPU_HAVE_HWLOC */
#ifdef STARPU_DEVEL
#  warning use sysinfo when available to get global size
#endif
	global_mem = 0;
#endif

	if (limit < 0)
		// No limit is defined, we return the global memory size
		return global_mem;
	else if ((size_t)limit * 1024*1024 > global_mem)
		// The requested limit is higher than what is available, we return the global memory size
		return global_mem;
	else
		// We limit the memory
		return limit*1024*1024;
}

int _starpu_cpu_driver_init(struct _starpu_worker *cpu_worker)
{
	int devid = cpu_worker->devid;

	_starpu_worker_start(cpu_worker, _STARPU_FUT_CPU_KEY);
	/* FIXME: when we have NUMA support, properly turn node number into NUMA node number */
	_starpu_memory_manager_set_global_memory_size(cpu_worker->memory_node, _starpu_cpu_get_global_mem_size(cpu_worker->memory_node, cpu_worker->config));

	snprintf(cpu_worker->name, sizeof(cpu_worker->name), "CPU %d", devid);
	snprintf(cpu_worker->short_name, sizeof(cpu_worker->short_name), "CPU %d", devid);

	cpu_worker->status = STATUS_UNKNOWN;

	_STARPU_TRACE_WORKER_INIT_END;

	/* tell the main thread that we are ready */
	STARPU_PTHREAD_MUTEX_LOCK(&cpu_worker->mutex);
	cpu_worker->worker_is_initialized = 1;
	STARPU_PTHREAD_COND_SIGNAL(&cpu_worker->ready_cond);
	STARPU_PTHREAD_MUTEX_UNLOCK(&cpu_worker->mutex);
	return 0;
}

int _starpu_cpu_driver_run_once(struct _starpu_worker *cpu_worker)
{
	unsigned memnode = cpu_worker->memory_node;
	int workerid = cpu_worker->workerid;

	_STARPU_TRACE_START_PROGRESS(memnode);
	_starpu_datawizard_progress(memnode, 1);
	_STARPU_TRACE_END_PROGRESS(memnode);

	struct _starpu_job *j;
	struct starpu_task *task;
	int res;

	task = _starpu_get_worker_task(cpu_worker, workerid, memnode);

	if (!task)
		return 0;

	j = _starpu_get_job_associated_to_task(task);

	/* can a cpu perform that task ? */
	if (!_STARPU_CPU_MAY_PERFORM(j))
	{
		/* put it and the end of the queue ... XXX */
		_starpu_push_task_to_workers(task);
		return 0;
	}

	int rank = 0;
	int is_parallel_task = (j->task_size > 1);

	enum starpu_perfmodel_archtype perf_arch;

	/* Get the rank in case it is a parallel task */
	if (is_parallel_task)
	{
		STARPU_PTHREAD_MUTEX_LOCK(&j->sync_mutex);
		rank = j->active_task_alias_count++;
		STARPU_PTHREAD_MUTEX_UNLOCK(&j->sync_mutex);

		struct _starpu_combined_worker *combined_worker;
		combined_worker = _starpu_get_combined_worker_struct(j->combined_workerid);

		cpu_worker->combined_workerid = j->combined_workerid;
		cpu_worker->worker_size = combined_worker->worker_size;
		cpu_worker->current_rank = rank;
		perf_arch = combined_worker->perf_arch;
	}
	else
	{
		cpu_worker->combined_workerid = cpu_worker->workerid;
		cpu_worker->worker_size = 1;
		cpu_worker->current_rank = 0;
		perf_arch = cpu_worker->perf_arch;
	}

	_starpu_set_current_task(j->task);
	cpu_worker->current_task = j->task;

	res = execute_job_on_cpu(j, task, cpu_worker, rank, perf_arch);

	_starpu_set_current_task(NULL);
	cpu_worker->current_task = NULL;

	if (res)
	{
		switch (res)
		{
		case -EAGAIN:
			_starpu_push_task_to_workers(task);
			return 0;
		default:
			STARPU_ABORT();
		}
	}

	/* In the case of combined workers, we need to inform the
	 * scheduler each worker's execution is over.
	 * Then we free the workers' task alias */
	if (is_parallel_task)
	{
		_starpu_sched_post_exec_hook(task);
		free(task);
	}

	if (rank == 0)
		_starpu_handle_job_termination(j);
	return 0;
}

int _starpu_cpu_driver_deinit(struct _starpu_worker *cpu_worker)
{
	_STARPU_TRACE_WORKER_DEINIT_START;

	unsigned memnode = cpu_worker->memory_node;
	_starpu_handle_all_pending_node_data_requests(memnode);

	/* In case there remains some memory that was automatically
	 * allocated by StarPU, we release it now. Note that data
	 * coherency is not maintained anymore at that point ! */
	_starpu_free_all_automatically_allocated_buffers(memnode);

	_STARPU_TRACE_WORKER_DEINIT_END(_STARPU_FUT_CPU_KEY);

	return 0;
}

void *
_starpu_cpu_worker(void *arg)
{
	struct _starpu_worker *args = arg;

	_starpu_cpu_driver_init(args);
	while (_starpu_machine_is_running())
		_starpu_cpu_driver_run_once(args);
	_starpu_cpu_driver_deinit(args);

	return NULL;
}

int _starpu_run_cpu(struct _starpu_worker *worker)
{
	worker->set = NULL;
	worker->worker_is_initialized = 0;
	_starpu_cpu_worker(worker);

	return 0;
}
