/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2013  INRIA
 * Copyright (C) 2013  Simon Archipoff
 *
 * 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 <core/jobs.h>
#include <core/workers.h>
#include <starpu_sched_component.h>
#include <starpu_thread_util.h>

#include <float.h>

#include "sched_component.h"

/* default implementation for component->pop_task()
 * just perform a recursive call on father
 */
static struct starpu_task * pop_task_component(struct starpu_sched_component * component)
{
	STARPU_ASSERT(component);
	struct starpu_task * task = NULL;
	int i;
	for(i=0; i < component->nfathers; i++)
	{
		if(component->fathers[i] == NULL)
			continue;
		else
		{
			task = component->fathers[i]->pop_task(component->fathers[i]);
			if(task)
				break;
		}
	}
	return task;
}

/******************************************************************************
 *          functions for struct starpu_sched_policy interface                *
 ******************************************************************************/
int starpu_sched_tree_push_task(struct starpu_task * task)
{
	STARPU_ASSERT(task);
	unsigned sched_ctx_id = task->sched_ctx;
	struct starpu_sched_tree *tree = starpu_sched_ctx_get_policy_data(sched_ctx_id);
	int workerid = starpu_worker_get_id();
	/* application should take tree->lock to prevent concurent acces from hypervisor
	 * worker take they own mutexes
	 */
	if(-1 == workerid)
		STARPU_PTHREAD_MUTEX_LOCK(&tree->lock);
	else
		_starpu_sched_component_lock_worker(workerid);
		
	int ret_val = tree->root->push_task(tree->root,task);
	if(-1 == workerid)
		STARPU_PTHREAD_MUTEX_UNLOCK(&tree->lock);
	else
		_starpu_sched_component_unlock_worker(workerid);
	return ret_val;
}

struct starpu_task * starpu_sched_tree_pop_task(unsigned sched_ctx STARPU_ATTRIBUTE_UNUSED)
{
	int workerid = starpu_worker_get_id();
	struct starpu_sched_component * component = starpu_sched_component_worker_get(workerid);

	/* _starpu_sched_component_lock_worker(workerid) is called by component->pop_task()
	 */
	struct starpu_task * task = component->pop_task(component);
	return task;
}

void starpu_sched_tree_add_workers(unsigned sched_ctx_id, int *workerids, unsigned nworkers)
{
	STARPU_ASSERT(sched_ctx_id < STARPU_NMAX_SCHED_CTXS);
	STARPU_ASSERT(workerids);
	struct starpu_sched_tree * t = starpu_sched_ctx_get_policy_data(sched_ctx_id);

	STARPU_PTHREAD_MUTEX_LOCK(&t->lock);
	_starpu_sched_component_lock_all_workers();

	unsigned i;
	for(i = 0; i < nworkers; i++)
		starpu_bitmap_set(t->workers, workerids[i]);

	starpu_sched_tree_update_workers_in_ctx(t);

	_starpu_sched_component_unlock_all_workers();
	STARPU_PTHREAD_MUTEX_UNLOCK(&t->lock);
}

void starpu_sched_tree_remove_workers(unsigned sched_ctx_id, int *workerids, unsigned nworkers)
{
	STARPU_ASSERT(sched_ctx_id < STARPU_NMAX_SCHED_CTXS);
	STARPU_ASSERT(workerids);
	struct starpu_sched_tree * t = starpu_sched_ctx_get_policy_data(sched_ctx_id);

	STARPU_PTHREAD_MUTEX_LOCK(&t->lock);
	_starpu_sched_component_lock_all_workers();

	unsigned i;
	for(i = 0; i < nworkers; i++)
		starpu_bitmap_unset(t->workers, workerids[i]);

	starpu_sched_tree_update_workers_in_ctx(t);

	_starpu_sched_component_unlock_all_workers();
	STARPU_PTHREAD_MUTEX_UNLOCK(&t->lock);
}

void starpu_sched_component_destroy_rec(struct starpu_sched_component * component)
{
	if(component == NULL)
		return;

	int i;
	if(component->nchildren > 0)
	{
		for(i=0; i < component->nchildren; i++)
			starpu_sched_component_destroy_rec(component->children[i]);
	}

	starpu_sched_component_destroy(component);
}

struct starpu_sched_tree * starpu_sched_tree_create(unsigned sched_ctx_id)
{
	STARPU_ASSERT(sched_ctx_id < STARPU_NMAX_SCHED_CTXS);
	struct starpu_sched_tree * t = malloc(sizeof(*t));
	memset(t, 0, sizeof(*t));
	t->sched_ctx_id = sched_ctx_id;
	t->workers = starpu_bitmap_create();
	STARPU_PTHREAD_MUTEX_INIT(&t->lock,NULL);
	return t;
}

void starpu_sched_tree_destroy(struct starpu_sched_tree * tree)
{
	STARPU_ASSERT(tree);
	if(tree->root)
		starpu_sched_component_destroy_rec(tree->root);
	starpu_bitmap_destroy(tree->workers);
	STARPU_PTHREAD_MUTEX_DESTROY(&tree->lock);
	free(tree);
}

static void starpu_sched_component_add_child(struct starpu_sched_component* component, struct starpu_sched_component * child)
{
	STARPU_ASSERT(component && child);
	STARPU_ASSERT(!starpu_sched_component_is_worker(component));
	int i;
	for(i = 0; i < component->nchildren; i++){
		STARPU_ASSERT(component->children[i] != component);
		STARPU_ASSERT(component->children[i] != NULL);
	}

	component->children = realloc(component->children, sizeof(struct starpu_sched_component *) * (component->nchildren + 1));
	component->children[component->nchildren] = child;
	component->nchildren++;
}

static void starpu_sched_component_remove_child(struct starpu_sched_component * component, struct starpu_sched_component * child)
{
	STARPU_ASSERT(component && child);
	STARPU_ASSERT(!starpu_sched_component_is_worker(component));
	int pos;
	for(pos = 0; pos < component->nchildren; pos++)
		if(component->children[pos] == child)
			break;
	STARPU_ASSERT(pos != component->nchildren);
	component->children[pos] = component->children[--component->nchildren];
}

static void starpu_sched_component_add_father(struct starpu_sched_component* component, struct starpu_sched_component * father)
{
	STARPU_ASSERT(component && father);
	int i;
	for(i = 0; i < component->nfathers; i++){
		STARPU_ASSERT(component->fathers[i] != component);
		STARPU_ASSERT(component->fathers[i] != NULL);
	}

	component->fathers = realloc(component->fathers, sizeof(struct starpu_sched_component *) * (component->nfathers + 1));
	component->fathers[component->nfathers] = father;
	component->nfathers++;
}

static void starpu_sched_component_remove_father(struct starpu_sched_component * component, struct starpu_sched_component * father)
{
	STARPU_ASSERT(component && father);
	int pos;
	for(pos = 0; pos < component->nfathers; pos++)
		if(component->fathers[pos] == father)
			break;
	STARPU_ASSERT(pos != component->nfathers);
	component->fathers[pos] = component->fathers[--component->nfathers];
}

struct starpu_bitmap * _starpu_get_worker_mask(unsigned sched_ctx_id)
{
	STARPU_ASSERT(sched_ctx_id < STARPU_NMAX_SCHED_CTXS);
	struct starpu_sched_tree * t = starpu_sched_ctx_get_policy_data(sched_ctx_id);
	STARPU_ASSERT(t);
	return t->workers;
}

static double estimated_load(struct starpu_sched_component * component)
{
	double sum = 0.0;
	int i;
	for( i = 0; i < component->nchildren; i++)
	{
		struct starpu_sched_component * c = component->children[i];
		sum += c->estimated_load(c);
	}
	return sum;
}

static double _starpu_sched_component_estimated_end_min(struct starpu_sched_component * component)
{
	STARPU_ASSERT(component);
	double min = DBL_MAX;
	int i;
	for(i = 0; i < component->nchildren; i++)
	{
		double tmp = component->children[i]->estimated_end(component->children[i]);
		if(tmp < min)
			min = tmp;
	}
	return min;
}

/* this function find the best implementation or an implementation that need to be calibrated for a worker available
 * and set prediction in *length. nan if a implementation need to be calibrated, 0.0 if no perf model are available
 * return false if no worker on the component can execute that task
 */
int starpu_sched_component_execute_preds(struct starpu_sched_component * component, struct starpu_task * task, double * length)
{
	STARPU_ASSERT(component && task);
	int can_execute = 0;
	starpu_task_bundle_t bundle = task->bundle;
	double len = DBL_MAX;
	

	int workerid;
	for(workerid = starpu_bitmap_first(component->workers_in_ctx);
	    workerid != -1;
	    workerid = starpu_bitmap_next(component->workers_in_ctx, workerid))
	{
		struct starpu_perfmodel_arch* archtype = starpu_worker_get_perf_archtype(workerid);
		int nimpl;
		for(nimpl = 0; nimpl < STARPU_MAXIMPLEMENTATIONS; nimpl++)
		{
			if(starpu_worker_can_execute_task(workerid,task,nimpl)
			   || starpu_combined_worker_can_execute_task(workerid, task, nimpl))
			{
				double d;
				can_execute = 1;
				if(bundle)
					d = starpu_task_bundle_expected_length(bundle, archtype, nimpl);
				else
					d = starpu_task_expected_length(task, archtype, nimpl);
				if(isnan(d))
				{
					*length = d;
					return can_execute;
						
				}
				if(_STARPU_IS_ZERO(d) && !can_execute)
				{
					can_execute = 1;
					continue;
				}
				if(d < len)
				{
					len = d;
				}
			}
		}
		if(STARPU_SCHED_COMPONENT_IS_HOMOGENEOUS(component))
			break;
	}

	if(len == DBL_MAX) /* we dont have perf model */
		len = 0.0; 
	if(length)
		*length = len;
	return can_execute;
}

/* very similar function that dont compute prediction */
int starpu_sched_component_can_execute_task(struct starpu_sched_component * component, struct starpu_task * task)
{
	STARPU_ASSERT(task);
	STARPU_ASSERT(component);
	unsigned nimpl;
	int worker;
	for (nimpl = 0; nimpl < STARPU_MAXIMPLEMENTATIONS; nimpl++)
		for(worker = starpu_bitmap_first(component->workers_in_ctx);
		    -1 != worker;
		    worker = starpu_bitmap_next(component->workers_in_ctx, worker))
			if (starpu_worker_can_execute_task(worker, task, nimpl)
			     || starpu_combined_worker_can_execute_task(worker, task, nimpl))
			    return 1;
	return 0;
}

/* compute the average of transfer length for tasks on all workers
 * maybe this should be optimised if all workers are under the same numa component
 */
double starpu_sched_component_transfer_length(struct starpu_sched_component * component, struct starpu_task * task)
{
	STARPU_ASSERT(component && task);
	int nworkers = starpu_bitmap_cardinal(component->workers_in_ctx);
	double sum = 0.0;
	int worker;
	if(STARPU_SCHED_COMPONENT_IS_SINGLE_MEMORY_NODE(component))
	{
		unsigned memory_node  = starpu_worker_get_memory_node(starpu_bitmap_first(component->workers_in_ctx));
		if(task->bundle)
			return starpu_task_bundle_expected_data_transfer_time(task->bundle,memory_node);
		else
			return starpu_task_expected_data_transfer_time(memory_node, task);
	}

	for(worker = starpu_bitmap_first(component->workers_in_ctx);
	    worker != -1;
	    worker = starpu_bitmap_next(component->workers_in_ctx, worker))
	{
		unsigned memory_node  = starpu_worker_get_memory_node(worker);
		if(task->bundle)
		{
			sum += starpu_task_bundle_expected_data_transfer_time(task->bundle,memory_node);
		}
		else
		{
			sum += starpu_task_expected_data_transfer_time(memory_node, task);
			/* sum += starpu_task_expected_conversion_time(task, starpu_worker_get_perf_archtype(worker), impl ?)
			 * I dont know what to do as we dont know what implementation would be used here...
			 */
		}
	}
	return sum / nworkers;
}

/* This function can be called by components when they think that a prefetching request can be submitted.
 * For example, it is currently used by the MCT component to begin the prefetching on accelerators 
 * on which it pushed tasks as soon as possible.
 */
void starpu_sched_component_prefetch_on_node(struct starpu_sched_component * component, struct starpu_task * task)
{
	if (starpu_get_prefetch_flag() && (!task->prefetched)
		&& (component->properties >= STARPU_SCHED_COMPONENT_SINGLE_MEMORY_NODE))
	{
		int worker = starpu_bitmap_first(component->workers_in_ctx);
		unsigned memory_node = starpu_worker_get_memory_node(worker);
		starpu_prefetch_task_input_on_node(task, memory_node);
		task->prefetched = 1;
	}
}

/* The default implementation of the can_push function is a recursive call to its fathers.
 * A personally-made can_push in a component (like in prio components) is necessary to catch
 * this recursive call somewhere, if the user wants to exploit it.
 */
static int starpu_sched_component_can_push(struct starpu_sched_component * component)
{
	STARPU_ASSERT(component);
	int ret = 0;
	if(component->nfathers > 0)
	{
		int i;
		for(i=0; i < component->nfathers; i++)
		{
			struct starpu_sched_component * father = component->fathers[i];
			if(father != NULL)
				ret = father->can_push(father);
			if(ret)
				break;
		}
	}
	return ret;
}

/* A can_pull call will try to wake up one worker associated to the childs of the
 * component. It is currenly called by components which holds a queue (like fifo and prio
 * components) to signify its childs that a task has been pushed on its local queue.
 */
static void starpu_sched_component_can_pull(struct starpu_sched_component * component)
{
	STARPU_ASSERT(component);
	STARPU_ASSERT(!starpu_sched_component_is_worker(component));
	int i;
	for(i = 0; i < component->nchildren; i++)
		component->children[i]->can_pull(component->children[i]);
}

/* Allows a worker to lock/unlock scheduling mutexes. Currently used in 
 * self-defined can_push calls to allow can_pull calls to take those mutexes while the 
 * current worker is pushing tasks on other workers (or itself). 
 */
void _starpu_sched_component_lock_scheduling(void)
{
	int workerid = starpu_worker_get_id();
	starpu_pthread_mutex_t *sched_mutex;
	starpu_pthread_cond_t *sched_cond;
	starpu_worker_get_sched_condition(workerid, &sched_mutex, &sched_cond);
	_starpu_sched_component_lock_worker(workerid);	
	STARPU_PTHREAD_MUTEX_LOCK(sched_mutex);
}

void _starpu_sched_component_unlock_scheduling(void)
{
	int workerid = starpu_worker_get_id();
	starpu_pthread_mutex_t *sched_mutex;
	starpu_pthread_cond_t *sched_cond;
	starpu_worker_get_sched_condition(workerid, &sched_mutex, &sched_cond);
	STARPU_PTHREAD_MUTEX_UNLOCK(sched_mutex);
	_starpu_sched_component_unlock_worker(workerid);	
}

void take_component_and_does_nothing(struct starpu_sched_component * component STARPU_ATTRIBUTE_UNUSED)
{
}

struct starpu_sched_component * starpu_sched_component_create(void)
{
	struct starpu_sched_component * component = malloc(sizeof(*component));
	memset(component,0,sizeof(*component));
	component->workers = starpu_bitmap_create();
	component->workers_in_ctx = starpu_bitmap_create();
	component->add_child = starpu_sched_component_add_child;
	component->remove_child = starpu_sched_component_remove_child;
	component->add_father = starpu_sched_component_add_father;
	component->remove_father = starpu_sched_component_remove_father;
	component->pop_task = pop_task_component;
	component->can_push = starpu_sched_component_can_push;
	component->can_pull = starpu_sched_component_can_pull;
	component->estimated_load = estimated_load;
	component->estimated_end = _starpu_sched_component_estimated_end_min;
	component->deinit_data = take_component_and_does_nothing;
	component->notify_change_workers = take_component_and_does_nothing;
	return component;
}

/* remove all child
 * for all child of component, if child->fathers[x] == component, set child->fathers[x] to null 
 * call component->deinit_data
 */
void starpu_sched_component_destroy(struct starpu_sched_component *component)
{
	STARPU_ASSERT(component);
	if(starpu_sched_component_is_worker(component))
		return;
	int i,j;
	for(i = 0; i < component->nchildren; i++)
	{
		struct starpu_sched_component * child = component->children[i];
		for(j = 0; j < child->nfathers; j++)
			if(child->fathers[j] == component)
				child->remove_father(child,component);

	}
	while(component->nchildren != 0)
		component->remove_child(component, component->children[0]);
	for(i = 0; i < component->nfathers; i++)
	{
		struct starpu_sched_component * father = component->fathers[i];
		for(j = 0; j < father->nchildren; j++)
			if(father->children[j] == component)
				father->remove_child(father,component);

	}
	while(component->nfathers != 0)
		component->remove_father(component, component->fathers[0]);
	component->deinit_data(component);
	free(component->children);
	free(component->fathers);
	starpu_bitmap_destroy(component->workers);
	starpu_bitmap_destroy(component->workers_in_ctx);
	free(component);
}

static void set_properties(struct starpu_sched_component * component)
{
	STARPU_ASSERT(component);
	component->properties = 0;

	int worker = starpu_bitmap_first(component->workers_in_ctx);
	if (worker == -1)
		return;
	uint32_t first_worker = _starpu_get_worker_struct(worker)->worker_mask;
	unsigned first_memory_node = _starpu_get_worker_struct(worker)->memory_node;
	int is_homogeneous = 1;
	int is_all_same_component = 1;
	for(;
	    worker != -1;
	    worker = starpu_bitmap_next(component->workers_in_ctx, worker))		
	{
		if(first_worker != _starpu_get_worker_struct(worker)->worker_mask)
			is_homogeneous = 0;
		if(first_memory_node != _starpu_get_worker_struct(worker)->memory_node)
			is_all_same_component = 0;
	}
	

	if(is_homogeneous)
		component->properties |= STARPU_SCHED_COMPONENT_HOMOGENEOUS;
	if(is_all_same_component)
		component->properties |= STARPU_SCHED_COMPONENT_SINGLE_MEMORY_NODE;
}


/* recursively set the component->workers member of component's subtree
 */
void _starpu_sched_component_update_workers(struct starpu_sched_component * component)
{
	STARPU_ASSERT(component);
	if(starpu_sched_component_is_worker(component))
		return;
	starpu_bitmap_unset_all(component->workers);
	int i;
	for(i = 0; i < component->nchildren; i++)
	{
		_starpu_sched_component_update_workers(component->children[i]);
		starpu_bitmap_or(component->workers, component->children[i]->workers);
		component->notify_change_workers(component);
	}
}

/* recursively set the component->workers_in_ctx in component's subtree
 */
void _starpu_sched_component_update_workers_in_ctx(struct starpu_sched_component * component, unsigned sched_ctx_id)
{
	STARPU_ASSERT(component);
	if(starpu_sched_component_is_worker(component))
		return;
	struct starpu_bitmap * workers_in_ctx = _starpu_get_worker_mask(sched_ctx_id);
	starpu_bitmap_unset_and(component->workers_in_ctx,component->workers, workers_in_ctx);
	int i,j;
	for(i = 0; i < component->nchildren; i++)
	{
		struct starpu_sched_component * child = component->children[i];
		_starpu_sched_component_update_workers_in_ctx(child, sched_ctx_id);
		for(j = 0; j < STARPU_NMAX_SCHED_CTXS; j++)
			if(child->fathers[j] == component)
			{
				starpu_bitmap_or(component->workers_in_ctx, child->workers_in_ctx);
				break;
			}
	}
	set_properties(component);
	component->notify_change_workers(component);
}

void starpu_sched_tree_update_workers_in_ctx(struct starpu_sched_tree * t)
{
	STARPU_ASSERT(t);
	_starpu_sched_component_update_workers_in_ctx(t->root, t->sched_ctx_id);
}

void starpu_sched_tree_update_workers(struct starpu_sched_tree * t)
{
	STARPU_ASSERT(t);
	_starpu_sched_component_update_workers(t->root);
}