starpu-max/src/core/disk_ops/disk_hdf5.c

/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2017  Inria
 *
 * 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 <fcntl.h>
#include <errno.h>
#include <common/config.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#include <hdf5.h>

#include <starpu.h>
#include <core/disk.h>
#include <core/perfmodel/perfmodel.h>

#ifndef O_BINARY
#define O_BINARY 0
#endif

#define NITER	_starpu_calibration_minimum
#define STARPU_CHUNK_DIM 4096

/* TODO: support disk-to-disk copy with HD5Ocopy */

/* ------------------- use HDF5 to write on disk -------------------  */

#ifndef H5_HAVE_THREADSAFE
static int nb_disk_open = 0;
static volatile int init_finished = 0;
static starpu_pthread_t global_thread;        /* This thread will perform each write/read because we don't have asynchronous functions */
static volatile int global_run;                        /* Ask to the thread if he can continue */
static starpu_pthread_mutex_t global_mutex;   /* Mutex is used to protect work_list and if HDF5 library is not safe */
static starpu_pthread_cond_t global_cond;
static struct _starpu_hdf5_work_list global_work_list;        /* This list contains the work for the hdf5 thread */
#endif

#ifdef H5_HAVE_THREADSAFE						

#define HDF5_VAR_THREAD fileBase->thread
#define HDF5_VAR_RUN fileBase->run
#define HDF5_VAR_MUTEX fileBase->mutex
#define HDF5_VAR_COND fileBase->cond
#define HDF5_VAR_WORK_LIST fileBase->work_list

#else									

#define HDF5_VAR_THREAD global_thread
#define HDF5_VAR_RUN global_run
#define HDF5_VAR_MUTEX global_mutex
#define HDF5_VAR_COND global_cond
#define HDF5_VAR_WORK_LIST global_work_list

#endif									



enum hdf5_work_type { READ, WRITE, FULL_READ, FULL_WRITE };

LIST_TYPE(_starpu_hdf5_work,
        enum hdf5_work_type type;
        struct starpu_hdf5_obj * obj;
        struct starpu_hdf5_base * base;
        void * ptr;
        off_t offset;
        size_t size;
        void * event;
);

struct starpu_hdf5_base
{
        hid_t fileID;
        char * path;
        unsigned created;       /* StarPU creates the HDF5 file */
        unsigned next_dataset_id;
        starpu_pthread_t thread;        /* This thread will perform each write/read because we don't have asynchronous functions */
        int run;                        /* Ask to the thread if he can continue */
	starpu_pthread_mutex_t mutex;   /* Mutex is used to protect work_list and if HDF5 library is not safe */
        starpu_pthread_cond_t cond;
        struct _starpu_hdf5_work_list work_list;        /* This list contains the work for the hdf5 thread */
};

struct starpu_hdf5_obj
{
        hid_t dataset;          /* describe this object in HDF5 file */
        char * path;            /* path where data are stored in HDF5 file */
	size_t size;
};

static inline void _starpu_hdf5_protect_start(void * base STARPU_ATTRIBUTE_UNUSED)
{
#ifndef H5_HAVE_THREADSAFE
        STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
#endif
}

static inline void _starpu_hdf5_protect_stop(void * base STARPU_ATTRIBUTE_UNUSED)
{
#ifndef H5_HAVE_THREADSAFE
        STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);
#endif
}

/* ------------------ Functions for internal thread -------------------- */

/* TODO : Dataspace may not be NATIVE_CHAR for opened data */
static void starpu_hdf5_full_read_internal(struct _starpu_hdf5_work * work)
{
        herr_t status;

        status = H5Dread(work->obj->dataset, H5T_NATIVE_CHAR, H5S_ALL, H5S_ALL, H5P_DEFAULT, work->ptr);
        STARPU_ASSERT_MSG(status >= 0, "Can not read data associed to this dataset (%s)\n", work->obj->path);
}

/* TODO : Dataspace may not be NATIVE_CHAR for opened data */
static void starpu_hdf5_full_write_internal(struct _starpu_hdf5_work * work)
{
        herr_t status;

	/* Update size of dataspace */
	if (work->size > work->obj->size)
	{
		/* Get official datatype */
		hid_t datatype = H5Dget_type(work->obj->dataset);
		hsize_t sizeDatatype = H5Tget_size(datatype);
		
		/* Count in number of elements */
		hsize_t extendsdim[1] = {work->size/sizeDatatype};
		status = H5Dset_extent (work->obj->dataset, extendsdim);
		STARPU_ASSERT_MSG(status >= 0, "Error when extending HDF5 dataspace !\n");
		work->obj->size = work->size;
	}

        /* Write ALL the dataspace */
        status = H5Dwrite(work->obj->dataset, H5T_NATIVE_CHAR, H5S_ALL, H5S_ALL, H5P_DEFAULT, work->ptr);
        STARPU_ASSERT_MSG(status >= 0, "Can not write data to this dataset (%s)\n", work->obj->path);
}

static void starpu_hdf5_read_internal(struct _starpu_hdf5_work * work)
{
        herr_t status;

        /* Get official datatype */
        hid_t datatype = H5Dget_type(work->obj->dataset);
        hsize_t sizeDatatype = H5Tget_size(datatype);

        /* count in element, not in byte */
        work->offset /= sizeDatatype;
        work->size /= sizeDatatype;

        /* duplicate the dataspace in the dataset */
        hid_t dataspace_select = H5Dget_space(work->obj->dataset);
        STARPU_ASSERT_MSG(dataspace_select >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);

        /* Select what we want of the duplicated dataspace (it's called an hyperslab). This operation is done on place */
        hsize_t offsets[1] = {work->offset};
        hsize_t count[1] = {work->size};
        /* stride and block size are NULL which is equivalent of a shift of 1 */
        status = H5Sselect_hyperslab(dataspace_select, H5S_SELECT_SET, offsets, NULL, count, NULL);
        STARPU_ASSERT_MSG(status >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);

        /* create the dataspace for the received data which describes ptr */
        hsize_t dims_receive[1] = {work->size};
        hid_t dataspace_receive = H5Screate_simple(1, dims_receive, NULL);
        STARPU_ASSERT_MSG(dataspace_receive >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);

        /* Receiver has to be an hyperslabs */
        offsets[0] = 0;
        count[0] = work->size;
        status = H5Sselect_hyperslab(dataspace_receive, H5S_SELECT_SET, offsets, NULL, count, NULL);
        STARPU_ASSERT_MSG(dataspace_receive >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);

        status = H5Dread(work->obj->dataset, datatype, dataspace_receive, dataspace_select, H5P_DEFAULT, work->ptr);
        STARPU_ASSERT_MSG(status >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);

        /* don't need these dataspaces */
        status = H5Sclose(dataspace_select);
        STARPU_ASSERT_MSG(status >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);
        status = H5Sclose(dataspace_receive);
        STARPU_ASSERT_MSG(status >= 0, "Error when reading this HDF5 dataset (%s)\n", work->obj->path);
}

static void starpu_hdf5_write_internal(struct _starpu_hdf5_work * work)
{
        herr_t status;

        /* Get official datatype */
        hid_t datatype = H5Dget_type(work->obj->dataset);
        hsize_t sizeDatatype = H5Tget_size(datatype);

	/* Update size of dataspace */
	if (work->size + work->offset > work->obj->size)
	{
		/* Count in number of elements */
		hsize_t extendsdim[1] = {(work->offset + work->size)/sizeDatatype};
		status = H5Dset_extent (work->obj->dataset, extendsdim);
		STARPU_ASSERT_MSG(status >= 0, "Error when extending HDF5 dataspace !\n");
		work->obj->size = work->offset + work->size;
	}

        /* count in element, not in byte */
        work->offset /= sizeDatatype;
        work->size /= sizeDatatype;

        /* duplicate the dataspace in the dataset */
        hid_t dataspace_select = H5Dget_space(work->obj->dataset);
        STARPU_ASSERT_MSG(dataspace_select >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);

        /* Select what we want of the duplicated dataspace (it's called an hyperslab). This operation is done on place */
        hsize_t offsets[1] = {work->offset};
        hsize_t count[1] = {work->size};
        /* stride and block size are NULL which is equivalent of a shift of 1 */
        status = H5Sselect_hyperslab(dataspace_select, H5S_SELECT_SET, offsets, NULL, count, NULL);
        STARPU_ASSERT_MSG(status >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);

        /* create the dataspace for the received data which describes ptr */
        hsize_t dims_send[1] = {work->size};
        hid_t dataspace_send = H5Screate_simple(1, dims_send, NULL);
        STARPU_ASSERT_MSG(dataspace_send >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);

        /* Receiver has to be an hyperslabs */
        offsets[0] = 0;
        count[0] = work->size;
        status = H5Sselect_hyperslab(dataspace_send, H5S_SELECT_SET, offsets, NULL, count, NULL);
        STARPU_ASSERT_MSG(dataspace_send >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);

        status = H5Dwrite(work->obj->dataset, datatype, dataspace_send, dataspace_select, H5P_DEFAULT, work->ptr);
        STARPU_ASSERT_MSG(status >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);

        /* don't need these dataspaces */
        status = H5Sclose(dataspace_select);
        STARPU_ASSERT_MSG(status >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);
        status = H5Sclose(dataspace_send);
        STARPU_ASSERT_MSG(status >= 0, "Error when writing this HDF5 dataset (%s)\n", work->obj->path);
}

static void * _starpu_hdf5_internal_thread(void * arg)
{
#ifdef H5_HAVE_THREADSAFE
        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) arg;
#endif
        while (HDF5_VAR_RUN || !_starpu_hdf5_work_list_empty(&HDF5_VAR_WORK_LIST))
        {
                STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
                if (_starpu_hdf5_work_list_empty(&HDF5_VAR_WORK_LIST) && HDF5_VAR_RUN)
                        STARPU_PTHREAD_COND_WAIT(&HDF5_VAR_COND, &HDF5_VAR_MUTEX);
                STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);

                /* We are the only consummer here, don't need to protect here */
                if (!_starpu_hdf5_work_list_empty(&HDF5_VAR_WORK_LIST))
                {
                        STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
                        struct _starpu_hdf5_work * work = _starpu_hdf5_work_list_pop_back(&HDF5_VAR_WORK_LIST);
                        STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);

                        _starpu_hdf5_protect_start(work->base);
                        switch(work->type)
                        {
                                case READ:
                                        starpu_hdf5_read_internal(work);
                                        break;

                                case WRITE:
                                        starpu_hdf5_write_internal(work);
                                        break;

                                case FULL_READ:
                                        starpu_hdf5_full_read_internal(work);
                                        break;

                                case FULL_WRITE:
                                        starpu_hdf5_full_write_internal(work);
                                        break;

                                default:
                                        STARPU_ABORT();
                        }
                        _starpu_hdf5_protect_stop(work->base);

                        /* Update event to tell it's finished */
                        starpu_sem_post((starpu_sem_t *) work->event);

                        free(work);
                }
        }

        STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
        STARPU_PTHREAD_COND_BROADCAST(&HDF5_VAR_COND);
        STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);

        return NULL;
}

static void _starpu_hdf5_create_thread(struct starpu_hdf5_base * fileBase)
{
	_starpu_hdf5_work_list_init(&HDF5_VAR_WORK_LIST);
        HDF5_VAR_RUN = 1;

        STARPU_PTHREAD_COND_INIT(&HDF5_VAR_COND, NULL);
        STARPU_PTHREAD_CREATE(&HDF5_VAR_THREAD, NULL, _starpu_hdf5_internal_thread, (void *) fileBase); 
}

/* returns the size in BYTES */
static hsize_t _starpu_get_size_obj(struct starpu_hdf5_obj * obj)
{
        herr_t status;

        hid_t dataspace = H5Dget_space(obj->dataset);
        STARPU_ASSERT_MSG(dataspace >= 0, "Can not get the size of this HDF5 dataset (%s)\n", obj->path);

        hsize_t dims[1];
        status = H5Sget_simple_extent_dims(dataspace, dims, NULL);
        STARPU_ASSERT_MSG(status >= 0, "Can not get the size of this HDF5 dataset (%s)\n", obj->path);

        hid_t datatype = H5Dget_type(obj->dataset);
        STARPU_ASSERT_MSG(datatype >= 0, "Can not get the size of this HDF5 dataset (%s)\n", obj->path);

        hsize_t sizeDatatype = H5Tget_size(datatype);
        STARPU_ASSERT_MSG(sizeDatatype > 0, "Can not get the size of this HDF5 dataset (%s)\n", obj->path);

        H5Sclose(dataspace);
        H5Tclose(datatype);

        return dims[0]*sizeDatatype;
}

static void starpu_hdf5_send_work(void *base, void *obj, void *buf, off_t offset, size_t size, void * event, enum hdf5_work_type type)
{
        struct starpu_hdf5_obj * dataObj = (struct starpu_hdf5_obj *) obj;
        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) base;

        struct _starpu_hdf5_work * work;
        _STARPU_MALLOC(work, sizeof(*work));

        work->type = type;
        work->obj = dataObj;
        work->base = fileBase;
        work->ptr = buf;
        work->offset = offset;
        work->size = size;
        work->event = event;

        STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
        _starpu_hdf5_work_list_push_front(&HDF5_VAR_WORK_LIST, work);
        /* Wake up internal thread */
        STARPU_PTHREAD_COND_BROADCAST(&HDF5_VAR_COND);
        STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);
}

static struct starpu_hdf5_obj * _starpu_hdf5_data_alloc(struct starpu_hdf5_base * fileBase,  char * name, size_t size)
{
        struct starpu_hdf5_obj * obj;
	_STARPU_MALLOC(obj, sizeof(*obj));

        _starpu_hdf5_protect_start((void *) fileBase);

        /* create a dataspace with one dimension of size elements */
        hsize_t dim[1] = {size};
        hsize_t maxdim[1] = {H5S_UNLIMITED};
        hid_t dataspace = H5Screate_simple(1, dim, maxdim);

        if (dataspace < 0)
        {
                free(obj);
                return NULL;
        }
	
	hsize_t chunkdim[1] = {STARPU_CHUNK_DIM};
	hid_t prop = H5Pcreate (H5P_DATASET_CREATE);
	herr_t status = H5Pset_chunk (prop, 1, chunkdim);
        STARPU_ASSERT_MSG(status >= 0, "Error when setting HDF5 property \n");

        /* create a dataset at location name, with data described by the dataspace.
         * Each element are like char in C (expected one byte) 
         */
        obj->dataset = H5Dcreate2(fileBase->fileID, name, H5T_NATIVE_CHAR, dataspace, H5P_DEFAULT, prop, H5P_DEFAULT);

        H5Sclose(dataspace);
	H5Pclose(prop);

        if (obj->dataset < 0)
        {
                free(obj);
                return NULL;
        }

        obj->path = name;
	obj->size = size;

        _starpu_hdf5_protect_stop((void *) fileBase);
        
        return obj;
}

static struct starpu_hdf5_obj * _starpu_hdf5_data_open(struct starpu_hdf5_base * fileBase,  char * name, size_t size)
{
        struct starpu_hdf5_obj * obj;
	_STARPU_MALLOC(obj, sizeof(*obj));

        _starpu_hdf5_protect_start((void *) fileBase);

        /* create a dataset at location name, with data described by the dataspace.
         * Each element are like char in C (expected one byte) 
         */
        obj->dataset = H5Dopen2(fileBase->fileID, name, H5P_DEFAULT);

        _starpu_hdf5_protect_stop((void *) fileBase);

        if (obj->dataset < 0)
        {
                free(obj);
                return NULL;
        }

        obj->path = name;
	obj->size = size;
        
        return obj;
}

static void *starpu_hdf5_plug(void *parameter, starpu_ssize_t size STARPU_ATTRIBUTE_UNUSED)
{
        struct starpu_hdf5_base * fileBase;
        _STARPU_MALLOC(fileBase, sizeof(struct starpu_hdf5_base));

#ifndef H5_HAVE_THREADSAFE
	int actual_nb_disk = STARPU_ATOMIC_ADD(&nb_disk_open, 1);
	if (actual_nb_disk == 1)
	{	
#endif
		STARPU_PTHREAD_MUTEX_INIT(&HDF5_VAR_MUTEX, NULL);
#ifndef H5_HAVE_THREADSAFE
	}
	else
	{
		while (!init_finished)
			;
	}
#endif

        _starpu_hdf5_protect_start(fileBase);

        struct stat buf;
        if (stat(parameter, &buf) != 0 || !S_ISREG(buf.st_mode))
        {
                /* The file doesn't exist or the directory exists => create the datafile */
                int id;
		_starpu_mkpath(parameter, S_IRWXU);
                fileBase->path = _starpu_mktemp(parameter, O_RDWR | O_BINARY, &id);
                if (!fileBase->path)
                {
                        free(fileBase);
                        _STARPU_ERROR("Can not create the HDF5 file (%s)", (char *) parameter);
			return NULL;
                }

                /* just use _starpu_mktemp_many to create a file, close the file descriptor */
                close(id);

                /* Truncate it */
                fileBase->fileID = H5Fcreate((char *)fileBase->path, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
                if (fileBase->fileID < 0) 
                {
                        free(fileBase); 
                        _STARPU_ERROR("Can not create the HDF5 file (%s)", (char *) parameter);
			return NULL;
                }
                fileBase->created = 1;
        } 
        else
        {
                /* Well, open it ! */
                char *path = strdup((char *)parameter);
		STARPU_ASSERT(path);

                fileBase->fileID = H5Fopen((char *)parameter, H5F_ACC_RDWR, H5P_DEFAULT);
                if (fileBase->fileID < 0) 
                {
                        free(fileBase);
			free(path);
                        _STARPU_ERROR("Can not open the HDF5 file (%s)", (char *) parameter);
			return NULL;
                }
                fileBase->created = 0;
                fileBase->path = path;
        }

#ifndef H5_HAVE_THREADSAFE
	if (actual_nb_disk == 1)
	{
#endif
		_starpu_hdf5_create_thread(fileBase);
#ifndef H5_HAVE_THREADSAFE
		init_finished = 1;
	}
#endif

#if H5_VERS_MAJOR > 1 || (H5_VERS_MAJOR == 1 && H5_VERS_MINOR > 10) || (H5_VERS_MAJOR == 1 && H5_VERS_MINOR == 10 && H5_VERS_RELEASE > 0) 
	H5Pset_file_space_strategy(fileBase->fileID, H5F_FSPACE_STRATEGY_FSM_AGGR, 0, 0);
#endif

        _starpu_hdf5_protect_stop(fileBase);

        fileBase->next_dataset_id = 0;

	return (void *) fileBase;
}

/* free memory allocated for the base */
static void starpu_hdf5_unplug(void *base)
{
#ifndef H5_HAVE_THREADSAFE
        int actual_nb_disk = STARPU_ATOMIC_ADD(&nb_disk_open, -1);
#endif

        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) base;
        herr_t status;

        STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);

#ifndef H5_HAVE_THREADSAFE
        if (actual_nb_disk == 0)
	{
#endif
		HDF5_VAR_RUN = 0;
		STARPU_PTHREAD_COND_BROADCAST(&HDF5_VAR_COND);
		STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);
		STARPU_PTHREAD_JOIN(HDF5_VAR_THREAD, NULL);
		STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
		STARPU_ASSERT(_starpu_hdf5_work_list_empty(&HDF5_VAR_WORK_LIST));
		/* the internal thread is deleted */
#ifndef H5_HAVE_THREADSAFE
	}
#endif

        status = H5Fclose(fileBase->fileID);

        STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);
#ifndef H5_HAVE_THREADSAFE
        if (actual_nb_disk == 0)
	{
#endif
		STARPU_PTHREAD_MUTEX_DESTROY(&HDF5_VAR_MUTEX);
#ifndef H5_HAVE_THREADSAFE
		init_finished = 0;
	}
#endif

        STARPU_ASSERT_MSG(status >= 0, "Can not unplug this HDF5 disk (%s)\n", fileBase->path);
        if (fileBase->created)
        {
                unlink(fileBase->path);        
        }
        else
        {
                /* Warn user about repack, because unlink dataset doesn't delete data in file */
                _STARPU_DISP("This disk (%s)  was used to store temporary data. You may use the h5repack command to reduce the size of the file... \n", fileBase->path);
        }
        free(fileBase->path);
	free(fileBase);
}

static void *starpu_hdf5_alloc(void *base, size_t size)
{
        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) base;
        struct starpu_hdf5_obj * obj;
        char * name;
        char * prefix = "STARPU_";
        char name_id[16];

        /* Save the name of the dataset */
        STARPU_PTHREAD_MUTEX_LOCK(&HDF5_VAR_MUTEX);
        snprintf(name_id, sizeof(name_id), "%u", fileBase->next_dataset_id);
        fileBase->next_dataset_id++;
        STARPU_PTHREAD_MUTEX_UNLOCK(&HDF5_VAR_MUTEX);

        /* name in HDF5 is like a path */
        _STARPU_MALLOC(name, 1+strlen(prefix)+strlen(name_id)+1);
	snprintf(name, 1+strlen(prefix)+strlen(name_id)+1, "/%s%s", prefix, name_id);

        obj = _starpu_hdf5_data_alloc(fileBase, name, size);

        if (!obj)
        {
                free(name);
        }

        return (void *) obj;
}

static void starpu_hdf5_free(void *base, void *obj, size_t size STARPU_ATTRIBUTE_UNUSED)
{
        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) base;
        struct starpu_hdf5_obj * dataObj = (struct starpu_hdf5_obj *) obj;
        herr_t status;

        _starpu_hdf5_protect_start(base);

        status = H5Dclose(dataObj->dataset);
        STARPU_ASSERT_MSG(status >= 0, "Can not free this HDF5 dataset (%s)\n", dataObj->path);

        /* remove the dataset link in the HDF5 
         * But it doesn't delete the space in the file */
        status = H5Ldelete(fileBase->fileID, dataObj->path, H5P_DEFAULT);
        STARPU_ASSERT_MSG(status >= 0, "Can not delete the link associed to this dataset (%s)\n", dataObj->path);

        _starpu_hdf5_protect_stop(base);

        free(dataObj->path);
        free(dataObj);
}

static void *starpu_hdf5_open(void *base, void *pos, size_t size)
{
        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) base;
        struct starpu_hdf5_obj * obj;
        char *name;

	name = strdup((char *)pos);
	STARPU_ASSERT(name);

        obj = _starpu_hdf5_data_open(fileBase, name, size);

        if (!obj)
        {
                free(name);
        }

        return (void *) obj;
}

static void starpu_hdf5_close(void *base, void *obj, size_t size STARPU_ATTRIBUTE_UNUSED)
{
        struct starpu_hdf5_obj * dataObj = (struct starpu_hdf5_obj *) obj;
        herr_t status;

        _starpu_hdf5_protect_start(base);

        status = H5Dclose(dataObj->dataset);
        STARPU_ASSERT_MSG(status >= 0, "Can not close this HDF5 dataset (%s)\n", dataObj->path);

        _starpu_hdf5_protect_stop(base);

        free(dataObj->path);
        free(dataObj);
}

static void starpu_hdf5_wait(void * event)
{
        starpu_sem_t * finished = (starpu_sem_t *) event;

        starpu_sem_wait(finished);
}

static int starpu_hdf5_test(void * event)
{
        starpu_sem_t * finished = (starpu_sem_t *) event;

        return starpu_sem_trywait(finished) == 0;
}

static int starpu_hdf5_full_read(void *base, void *obj, void **ptr, size_t *size)
{
        struct starpu_hdf5_obj * dataObj = (struct starpu_hdf5_obj *) obj;

        starpu_sem_t finished;
        starpu_sem_init(&finished, 0, 0);

        _starpu_hdf5_protect_start(base);
        *size = _starpu_get_size_obj(dataObj);
        _starpu_hdf5_protect_stop(base);

        starpu_malloc_flags(ptr, *size, 0); 

        starpu_hdf5_send_work(base, obj, *ptr, 0, *size, (void*) &finished, FULL_READ);
        
        starpu_hdf5_wait(&finished);

        starpu_sem_destroy(&finished);
        
        return 0;
}

static int starpu_hdf5_full_write(void *base, void *obj, void *ptr, size_t size)
{
        starpu_sem_t finished;
        starpu_sem_init(&finished, 0, 0);

        starpu_hdf5_send_work(base, obj, ptr, 0, size, (void*) &finished, FULL_WRITE);

        starpu_hdf5_wait(&finished);

        starpu_sem_destroy(&finished);

        return 0;
}

static int starpu_hdf5_read(void *base, void *obj, void *buf, off_t offset, size_t size)
{
        starpu_sem_t finished;
        starpu_sem_init(&finished, 0, 0);

        starpu_hdf5_send_work(base, obj, buf, offset, size, (void*) &finished, READ);

        starpu_hdf5_wait(&finished);

        starpu_sem_destroy(&finished);

        return 0;
}

static int starpu_hdf5_write(void *base, void *obj, const void *buf, off_t offset, size_t size)
{
        starpu_sem_t finished;
        starpu_sem_init(&finished, 0, 0);

        starpu_hdf5_send_work(base, obj, (void *) buf, offset, size, (void*) &finished, WRITE);

        starpu_hdf5_wait(&finished);

        starpu_sem_destroy(&finished);

        return 0;
}

static void * starpu_hdf5_async_read(void *base, void *obj, void *buf, off_t offset, size_t size)
{
        starpu_sem_t * finished;
        _STARPU_MALLOC(finished, sizeof(*finished));
        starpu_sem_init(finished, 0, 0);

        starpu_hdf5_send_work(base, obj, buf, offset, size, (void*) finished, READ);

        return finished;
}

static void * starpu_hdf5_async_write(void *base, void *obj, void *buf, off_t offset, size_t size)
{
        starpu_sem_t * finished;
        _STARPU_MALLOC(finished, sizeof(*finished));
        starpu_sem_init(finished, 0, 0);

        starpu_hdf5_send_work(base, obj, (void *) buf, offset, size, (void*) finished, WRITE);

        return finished;
}

static void starpu_hdf5_free_request(void * event)
{
        starpu_sem_destroy(event);
        free(event);
}

static int get_hdf5_bandwidth_between_disk_and_main_ram(unsigned node, void *base)
{
	unsigned iter;
	double timing_slowness, timing_latency;
	double start;
	double end;
	char *buf;
        struct starpu_hdf5_base * fileBase = (struct starpu_hdf5_base *) base;

	srand(time(NULL));
	starpu_malloc_flags((void **) &buf, STARPU_DISK_SIZE_MIN, 0);
	STARPU_ASSERT(buf != NULL);

	/* allocate memory */
	void *mem = _starpu_disk_alloc(node, STARPU_DISK_SIZE_MIN);
	/* fail to alloc */
	if (mem == NULL)
		return 0;

	memset(buf, 0, STARPU_DISK_SIZE_MIN);

	/* Measure upload slowness */
	start = starpu_timing_now();
	for (iter = 0; iter < NITER; ++iter)
	{
		_starpu_disk_write(STARPU_MAIN_RAM, node, mem, buf, 0, STARPU_DISK_SIZE_MIN, NULL);

	}
	end = starpu_timing_now();
	timing_slowness = end - start;

	/* free memory */
	starpu_free_flags(buf, STARPU_DISK_SIZE_MIN, 0);

	starpu_malloc_flags((void**) &buf, sizeof(char), 0);
	STARPU_ASSERT(buf != NULL);

	*buf = 0;

	/* Measure latency */
	start = starpu_timing_now();
	for (iter = 0; iter < NITER; ++iter)
	{
		_starpu_disk_write(STARPU_MAIN_RAM, node, mem, buf, rand() % (STARPU_DISK_SIZE_MIN -1) , 1, NULL);
	}
	end = starpu_timing_now();
	timing_latency = end - start;

	_starpu_disk_free(node, mem, STARPU_DISK_SIZE_MIN);
	starpu_free_flags(buf, sizeof(char), 0);

	_starpu_save_bandwidth_and_latency_disk((NITER/timing_slowness)*STARPU_DISK_SIZE_MIN, (NITER/timing_slowness)*STARPU_DISK_SIZE_MIN,
			timing_latency/NITER, timing_latency/NITER, node, fileBase->path);
	return 1;
}

struct starpu_disk_ops starpu_disk_hdf5_ops =
{
	.alloc = starpu_hdf5_alloc,
	.free = starpu_hdf5_free,
	.open = starpu_hdf5_open,
	.close = starpu_hdf5_close,
	.read = starpu_hdf5_read,
	.write = starpu_hdf5_write,
	.plug = starpu_hdf5_plug,
	.unplug = starpu_hdf5_unplug,
	.copy = NULL,
	.bandwidth = get_hdf5_bandwidth_between_disk_and_main_ram,
	.full_read = starpu_hdf5_full_read,
	.full_write = starpu_hdf5_full_write,

	.async_read = starpu_hdf5_async_read,
	.async_write = starpu_hdf5_async_write,
	.wait_request = starpu_hdf5_wait,
	.test_request = starpu_hdf5_test,
	.free_request = starpu_hdf5_free_request
};