Source

mpi3-fortran / ompi / mca / fcoll / dynamic / fcoll_dynamic_file_read_all.c

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/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2005 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * Copyright (c) 2008-2011 University of Houston. All rights reserved.
 * $COPYRIGHT$
 *
 * Additional copyrights may follow
 *
 * $HEADER$
 */

 #include "ompi_config.h"
 #include "fcoll_dynamic.h"

 #include "mpi.h"
 #include "ompi/constants.h"
 #include "ompi/mca/fcoll/fcoll.h"
 #include "ompi/mca/io/ompio/io_ompio.h"
 #include "ompi/mca/io/io.h"
 #include "math.h"
 #include "ompi/mca/pml/pml.h"
 #include <unistd.h>

 #define TIME_BREAKDOWN 1
 #define DEBUG_ON 0

 /*Used for loading file-offsets per aggregator*/
 typedef struct local_io_array{
   OMPI_MPI_OFFSET_TYPE offset;
   MPI_Aint             length;  
   int                  process_id;
 }local_io_array;


 static int read_heap_sort (local_io_array *io_array,
			    int num_entries,
			    int *sorted);



 int
 mca_fcoll_dynamic_file_read_all (mca_io_ompio_file_t *fh, 
				  void *buf, 
				  int count, 
				  struct ompi_datatype_t *datatype, 
				  ompi_status_public_t *status)
 {
     MPI_Aint position = 0;
     MPI_Aint total_bytes = 0;          /* total bytes to be read */
     MPI_Aint bytes_to_read_in_cycle = 0; /* left to be read in a cycle*/
     MPI_Aint bytes_per_cycle = 0;      /* total read in each cycle by each process*/
     int index = 0, ret=OMPI_SUCCESS;
     int cycles = 0;
     int i=0, j=0, l=0;
     int n=0; /* current position in total_bytes_per_process array */
     MPI_Aint bytes_remaining = 0; /* how many bytes have been read from the current
					 value from total_bytes_per_process */
     int *sorted_file_offsets=NULL, entries_per_aggregator=0;
     int bytes_received = 0;
     int blocks = 0;
     /* iovec structure and count of the buffer passed in */
     uint32_t iov_count = 0;
     struct iovec *decoded_iov = NULL;
     int iov_index = 0;
     size_t current_position = 0;
     struct iovec *local_iov_array=NULL, *global_iov_array=NULL;
     char *receive_buf = NULL;
     MPI_Aint *memory_displacements=NULL;
     /* global iovec at the readers that contain the iovecs created from
	file_set_view */
     uint32_t total_fview_count = 0;
     int local_count = 0;
     int *fview_count = NULL, *disp_index=NULL, *temp_disp_index=NULL;
     int current_index=0, temp_index=0;
     int **blocklen_per_process=NULL;
     MPI_Aint **displs_per_process=NULL;
     char *global_buf = NULL;
     MPI_Aint global_count = 0;
     local_io_array *file_offsets_for_agg=NULL;

     /* array that contains the sorted indices of the global_iov */
     int *sorted = NULL;
     int *displs = NULL;
     size_t max_data = 0; 
     int *bytes_per_process = NULL;
     MPI_Aint *total_bytes_per_process = NULL;
     ompi_datatype_t **sendtype = NULL;
     MPI_Request *send_req=NULL, *recv_req=NULL;


 #if TIME_BREAKDOWN
     double read_time = 0.0, start_read_time = 0.0, end_read_time = 0.0;
     double rcomm_time = 0.0, start_rcomm_time = 0.0, end_rcomm_time = 0.0;
     double read_exch = 0.0, start_rexch = 0.0, end_rexch = 0.0;
     print_entry nentry;
 #endif


     if (opal_datatype_is_contiguous_memory_layout(&datatype->super,1)) {
	 fh->f_flags |= OMPIO_CONTIGUOUS_MEMORY;
     }
     /**************************************************************************
      ** In case the data is not contigous in memory, decode it into an iovec **
      **************************************************************************/
     if (! (fh->f_flags & OMPIO_CONTIGUOUS_MEMORY)) {
       ret = ompi_io_ompio_decode_datatype (fh,
					    datatype,
					    count,
					    buf,
					    &max_data,
					    &decoded_iov,
					    &iov_count);
       if (OMPI_SUCCESS != ret){
	 goto exit;
       }
     }
     else {
	 max_data = count * datatype->super.size;
     }

     if ( MPI_STATUS_IGNORE != status ) {
	 status->_ucount = max_data;
     }

     if (! (fh->f_flags & OMPIO_AGGREGATOR_IS_SET)) {
       ret = ompi_io_ompio_set_aggregator_props (fh, 
						 mca_fcoll_dynamic_num_io_procs,
						 max_data);
       if (OMPI_SUCCESS != ret){
	 goto exit;
       }

     }

     total_bytes_per_process = (MPI_Aint*)malloc
	 (fh->f_procs_per_group*sizeof(MPI_Aint));
     if (NULL == total_bytes_per_process) {
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
     }

     ret = ompi_io_ompio_allgather_array (&max_data,
					  1,
					  MPI_LONG,
					  total_bytes_per_process,
					  1,
					  MPI_LONG,
					  fh->f_aggregator_index,
					  fh->f_procs_in_group,
					  fh->f_procs_per_group,
					  fh->f_comm);
     if (OMPI_SUCCESS != ret){
       goto exit;
     }

     for (i=0 ; i<fh->f_procs_per_group ; i++) {
	 total_bytes += total_bytes_per_process[i];
     }

     if (NULL != total_bytes_per_process) {
	 free (total_bytes_per_process);
	 total_bytes_per_process = NULL;
     }

     /*********************************************************************
      *** Generate the File offsets/lengths corresponding to this write ***
      ********************************************************************/
     ret = ompi_io_ompio_generate_current_file_view (fh, 
						     max_data,
						     &local_iov_array,
						     &local_count);

     if (ret != OMPI_SUCCESS){
       goto exit;
     }

     

     /* #########################################################*/

     /*************************************************************
      *** ALLGather the File View information at all processes ***
      *************************************************************/

     fview_count = (int *) malloc (fh->f_procs_per_group * sizeof (int));
     if (NULL == fview_count) {
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
     }

     ret = ompi_io_ompio_allgather_array (&local_count,
					  1,
					  MPI_INT,
					  fview_count,
					  1,
					  MPI_INT,
					  fh->f_aggregator_index,
					  fh->f_procs_in_group,
					  fh->f_procs_per_group,
					  fh->f_comm);

     if (OMPI_SUCCESS != ret){
       goto exit;
     }

     displs = (int*)malloc (fh->f_procs_per_group*sizeof(int));
     if (NULL == displs) {
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
     }

     displs[0] = 0;
     total_fview_count = fview_count[0];
     for (i=1 ; i<fh->f_procs_per_group ; i++) {
	 total_fview_count += fview_count[i];
	 displs[i] = displs[i-1] + fview_count[i-1];
     }

 #if DEBUG_ON
     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {
	 for (i=0 ; i<fh->f_procs_per_group ; i++) {
	     printf ("%d: PROCESS: %d  ELEMENTS: %d  DISPLS: %d\n",
		     fh->f_rank,
		     i,
		     fview_count[i],
		     displs[i]);
	 }
     }
 #endif

     /* allocate the global iovec  */
     if (0 != total_fview_count) {
       global_iov_array = (struct iovec*)malloc (total_fview_count * 
						 sizeof(struct iovec));
       if (NULL == global_iov_array) {
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
       }
     }

     if (fh->f_flags & OMPIO_UNIFORM_FVIEW) {

       ret = ompi_io_ompio_allgather_array (local_iov_array,
					    local_count,
					    fh->f_iov_type,
					    global_iov_array,
					    local_count,
					    fh->f_iov_type,
					    fh->f_aggregator_index,
					    fh->f_procs_in_group,
					    fh->f_procs_per_group,
					    fh->f_comm);

       if (OMPI_SUCCESS != ret){
	 goto exit;
       }
     }
     else { 
       ret =  ompi_io_ompio_allgatherv_array (local_iov_array,
					      local_count,
					      fh->f_iov_type,
					      global_iov_array,
					      fview_count,
					      displs,
					      fh->f_iov_type,
					      fh->f_aggregator_index,
					      fh->f_procs_in_group,
					      fh->f_procs_per_group,
					      fh->f_comm);

       if (OMPI_SUCCESS != ret){
	 goto exit;
       }
     }
     /* sort it */
     if (0 != total_fview_count) {
	 sorted = (int *)malloc (total_fview_count * sizeof(int));
	 if (NULL == sorted) {
	     opal_output (1, "OUT OF MEMORY\n");
	     ret = OMPI_ERR_OUT_OF_RESOURCE;
	     goto exit;
	 }
	 ompi_io_ompio_sort_iovec (global_iov_array, total_fview_count, sorted);
     }

     if (NULL != local_iov_array) {
	 free (local_iov_array);
	 local_iov_array = NULL;
     }

 #if DEBUG_ON       
     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {
	 for (i=0 ; i<total_fview_count ; i++) {
	     printf("%d: OFFSET: %p   LENGTH: %d\n",
		    fh->f_rank,
		    global_iov_array[sorted[i]].iov_base,
		    global_iov_array[sorted[i]].iov_len);
	 }
     }
 #endif

     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {

       disp_index = (int *)malloc (fh->f_procs_per_group * sizeof (int));
       if (NULL == disp_index) {
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
       }

       blocklen_per_process = (int **)malloc (fh->f_procs_per_group * sizeof (int*));
       if (NULL == blocklen_per_process) {
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
       }

       displs_per_process = (MPI_Aint **)malloc (fh->f_procs_per_group * sizeof (MPI_Aint*));
       if (NULL == displs_per_process){
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
       }

       for (i=0;i<fh->f_procs_per_group;i++){
	 blocklen_per_process[i] = NULL;
	 displs_per_process[i] = NULL;
       }
     }


     /*
      * Calculate how many bytes are read in each cycle
      */
     bytes_per_cycle = mca_fcoll_dynamic_cycle_buffer_size;
     cycles = ceil((double)total_bytes/bytes_per_cycle);

     n = 0; 
     bytes_remaining = 0;  
     current_index = 0;


 #if TIME_BREAKDOWN
     start_rexch = MPI_Wtime();
 #endif
     for (index = 0; index < cycles; index++) {
       /* Getting ready for next cycle
	  Initializing and freeing buffers */
       if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {	
	 if (NULL == sendtype){
	   sendtype = (ompi_datatype_t **) 
	     malloc (fh->f_procs_per_group  * sizeof(ompi_datatype_t *));
	   if (NULL == sendtype) {
	     opal_output (1, "OUT OF MEMORY\n");
	     ret = OMPI_ERR_OUT_OF_RESOURCE;
	     goto exit;
	   }
	 }
	 
	 for(l=0;l<fh->f_procs_per_group;l++){
	 
	   disp_index[l] =  1;

	   if (NULL != blocklen_per_process[l]){
	     free(blocklen_per_process[l]);
	     blocklen_per_process[l] = NULL;
	   }
	   if (NULL != displs_per_process[l]){
	     free(displs_per_process[l]);
	     displs_per_process[l] = NULL;
	   }
	   blocklen_per_process[l] = (int *) calloc (1, sizeof(int));
	   if (NULL == blocklen_per_process[l]) {
	     opal_output (1, "OUT OF MEMORY for blocklen\n");
	     ret = OMPI_ERR_OUT_OF_RESOURCE;
	     goto exit;
	   }
	   displs_per_process[l] = (MPI_Aint *) calloc (1, sizeof(MPI_Aint));
	   if (NULL == displs_per_process[l]){      
	     opal_output (1, "OUT OF MEMORY for displs\n");
	     ret = OMPI_ERR_OUT_OF_RESOURCE;
	     goto exit;
	   }
	 }

	 if (NULL != sorted_file_offsets){
	   free(sorted_file_offsets);
	   sorted_file_offsets = NULL;
	 }

	 if(NULL != file_offsets_for_agg){
	   free(file_offsets_for_agg);
	   file_offsets_for_agg = NULL;
	 }
	 if (NULL != memory_displacements){
	   free(memory_displacements);
	   memory_displacements = NULL;
	 }
       }
       

       if (cycles-1 == index) {
	 bytes_to_read_in_cycle = total_bytes - bytes_per_cycle*index;
       }
       else {
	 bytes_to_read_in_cycle = bytes_per_cycle;
       }
       
 #if DEBUG_ON
       if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {
	 printf ("****%d: CYCLE %d   Bytes %d**********\n",
		 fh->f_rank,
		 index, 
		 bytes_to_write_in_cycle);
       }
 #endif

       /* Calculate how much data will be contributed in this cycle 
	    by each process*/
       bytes_received = 0;

       while (bytes_to_read_in_cycle) {
	 blocks = fview_count[0];
	 for (j=0 ; j<fh->f_procs_per_group ; j++) {
	   if (sorted[current_index] < blocks) {
	     n = j;
	     break;
	   }
	   else {
	     blocks += fview_count[j+1];
	   }
	 }
	 if (bytes_remaining) {
	   if (bytes_remaining <= bytes_to_read_in_cycle) {

	     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {
	       blocklen_per_process[n][disp_index[n] - 1] = bytes_remaining;
	       displs_per_process[n][disp_index[n] - 1] =
		 (OPAL_PTRDIFF_TYPE)global_iov_array[sorted[current_index]].iov_base +
		 (global_iov_array[sorted[current_index]].iov_len - bytes_remaining);
	     }
	     if (fh->f_procs_in_group[n] == fh->f_rank) {
	       bytes_received += bytes_remaining;
	     }
	     current_index ++;
	     bytes_to_read_in_cycle -= bytes_remaining;
	     bytes_remaining = 0;
	     if (fh->f_procs_in_group[fh->f_aggregator_index] == 
		 fh->f_rank) {		
	       blocklen_per_process[n] = (int *) realloc
		 ((void *)blocklen_per_process[n], (disp_index[n]+1)*sizeof(int));
	       displs_per_process[n] = (MPI_Aint *) realloc
		 ((void *)displs_per_process[n], (disp_index[n]+1)*sizeof(MPI_Aint));
	       blocklen_per_process[n][disp_index[n]] = 0;
	       displs_per_process[n][disp_index[n]] = 0;
	       disp_index[n] += 1;
	     }
	     continue;
	   } 
	   else {
	     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {
	       blocklen_per_process[n][disp_index[n] - 1] = bytes_to_read_in_cycle;
	       displs_per_process[n][disp_index[n] - 1] = 
		 (OPAL_PTRDIFF_TYPE)global_iov_array[sorted[current_index]].iov_base +
		 (global_iov_array[sorted[current_index]].iov_len
		  - bytes_remaining);
	     }
	     if (fh->f_procs_in_group[n] == fh->f_rank) {
	       bytes_received += bytes_to_read_in_cycle;
	     }
	     bytes_remaining -= bytes_to_read_in_cycle;
	     bytes_to_read_in_cycle = 0;
	     break;
	   }
	 }
	 else {
	   if (bytes_to_read_in_cycle < 
		   (MPI_Aint) global_iov_array[sorted[current_index]].iov_len) {
	     if (fh->f_procs_in_group[fh->f_aggregator_index] == 
		 fh->f_rank) {

	       blocklen_per_process[n][disp_index[n] - 1] = bytes_to_read_in_cycle;
	       displs_per_process[n][disp_index[n] - 1] = 
		 (OPAL_PTRDIFF_TYPE)global_iov_array[sorted[current_index]].iov_base ;
	     }

	     if (fh->f_procs_in_group[n] == fh->f_rank) {
	       bytes_received += bytes_to_read_in_cycle;
	     }
	     bytes_remaining = global_iov_array[sorted[current_index]].iov_len - 
	       bytes_to_read_in_cycle;
	     bytes_to_read_in_cycle = 0;
	     break;
	   }
	   else {
	     if (fh->f_procs_in_group[fh->f_aggregator_index] == 
		 fh->f_rank) {
	       blocklen_per_process[n][disp_index[n] - 1] =
		 global_iov_array[sorted[current_index]].iov_len;
	       displs_per_process[n][disp_index[n] - 1] = (OPAL_PTRDIFF_TYPE)
		 global_iov_array[sorted[current_index]].iov_base;
	       blocklen_per_process[n] = 
		 (int *) realloc ((void *)blocklen_per_process[n], (disp_index[n]+1)*sizeof(int));
	       displs_per_process[n] = (MPI_Aint *)realloc
		 ((void *)displs_per_process[n], (disp_index[n]+1)*sizeof(MPI_Aint));
	       blocklen_per_process[n][disp_index[n]] = 0;
	       displs_per_process[n][disp_index[n]] = 0;
	       disp_index[n] += 1;
	     }
	     if (fh->f_procs_in_group[n] == fh->f_rank) {
	       bytes_received += 
		 global_iov_array[sorted[current_index]].iov_len;
	     }
	     bytes_to_read_in_cycle -= 
	       global_iov_array[sorted[current_index]].iov_len;
	     current_index ++;
	     continue;
	   }
	 }
       }
       /* Calculate the displacement on where to put the data and allocate
	  the recieve buffer (global_buf) */
       if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {
	 entries_per_aggregator=0;
	 for (i=0;i<fh->f_procs_per_group; i++){
	   for (j=0;j<disp_index[i];j++){
	     if (blocklen_per_process[i][j] > 0) 
	       entries_per_aggregator++ ;
	   }
	 }
	 if (entries_per_aggregator > 0){
	   file_offsets_for_agg = (local_io_array *)
	     malloc(entries_per_aggregator*sizeof(local_io_array));
	   if (NULL == file_offsets_for_agg) {
	     opal_output (1, "OUT OF MEMORY\n");
	     ret = OMPI_ERR_OUT_OF_RESOURCE;
	     goto exit;
	   }
	   sorted_file_offsets = (int *)
	     malloc (entries_per_aggregator*sizeof(int));
	   if (NULL == sorted_file_offsets){
	     opal_output (1, "OUT OF MEMORY\n");
	     ret =  OMPI_ERR_OUT_OF_RESOURCE;
	     goto exit;
	   }
	   /*Moving file offsets to an IO array!*/
	   temp_index = 0;
	   global_count = 0;
	   for (i=0;i<fh->f_procs_per_group; i++){
	     for(j=0;j<disp_index[i];j++){
	       if (blocklen_per_process[i][j] > 0){
		   file_offsets_for_agg[temp_index].length =
		     blocklen_per_process[i][j];
		   global_count += blocklen_per_process[i][j];
		   file_offsets_for_agg[temp_index].process_id = i;
		   file_offsets_for_agg[temp_index].offset = 
		     displs_per_process[i][j];
		   temp_index++;
	       }
	     }
	   }
	 }
	 else{
	   continue;
	 }

	 read_heap_sort (file_offsets_for_agg,
			 entries_per_aggregator,
			 sorted_file_offsets); 

	 memory_displacements = (MPI_Aint *) malloc 
	   (entries_per_aggregator * sizeof(MPI_Aint));
	 memory_displacements[sorted_file_offsets[0]] = 0;
	 for (i=1; i<entries_per_aggregator; i++){
	   memory_displacements[sorted_file_offsets[i]] = 
	     memory_displacements[sorted_file_offsets[i-1]] + 
	     file_offsets_for_agg[sorted_file_offsets[i-1]].length;
	 }

	 global_buf = (char *) malloc (global_count * sizeof(char));
	 if (NULL == global_buf){
	   opal_output(1, "OUT OF MEMORY\n");
	   ret = OMPI_ERR_OUT_OF_RESOURCE;
	   goto exit;
	 }

	  fh->f_io_array = (mca_io_ompio_io_array_t *) malloc 
	    (entries_per_aggregator * sizeof (mca_io_ompio_io_array_t));
	  if (NULL == fh->f_io_array) {
	    opal_output(1, "OUT OF MEMORY\n");
	    return OMPI_ERR_OUT_OF_RESOURCE;
	  }

	 fh->f_num_of_io_entries = 0;
	 fh->f_io_array[fh->f_num_of_io_entries].offset = 
	   (IOVBASE_TYPE *)file_offsets_for_agg[sorted_file_offsets[0]].offset;
	 fh->f_io_array[fh->f_num_of_io_entries].length = 
	   file_offsets_for_agg[sorted_file_offsets[0]].length;
	 fh->f_io_array[fh->f_num_of_io_entries].memory_address = 
	   global_buf+memory_displacements[sorted_file_offsets[0]];
	 fh->f_num_of_io_entries++;
	 for (i=1;i<entries_per_aggregator;i++){
	   if (file_offsets_for_agg[sorted_file_offsets[i-1]].offset + 
	       file_offsets_for_agg[sorted_file_offsets[i-1]].length ==
	       file_offsets_for_agg[sorted_file_offsets[i]].offset){
	     fh->f_io_array[fh->f_num_of_io_entries - 1].length +=
	       file_offsets_for_agg[sorted_file_offsets[i]].length;	
	   }
	   else{
	     fh->f_io_array[fh->f_num_of_io_entries].offset = 
	       (IOVBASE_TYPE *)file_offsets_for_agg[sorted_file_offsets[i]].offset;
	     fh->f_io_array[fh->f_num_of_io_entries].length = 
	       file_offsets_for_agg[sorted_file_offsets[i]].length;
	     fh->f_io_array[fh->f_num_of_io_entries].memory_address = 
	       global_buf+memory_displacements[sorted_file_offsets[i]];
	     fh->f_num_of_io_entries++;
	   }
	 }


 #if TIME_BREAKDOWN
	 start_read_time = MPI_Wtime();
 #endif

	 if (fh->f_num_of_io_entries) {
	   if (OMPI_SUCCESS != fh->f_fbtl->fbtl_preadv (fh, NULL)) {
	     opal_output (1, "READ FAILED\n");
	     return OMPI_ERROR;
	   }
	 }

 #if TIME_BREAKDOWN
	 end_read_time = MPI_Wtime();
	 read_time += end_read_time - start_read_time;
 #endif
	 /**********************************************************
	  ******************** DONE READING ************************
	  *********************************************************/

	 temp_disp_index = (int *)calloc (1, fh->f_procs_per_group * sizeof (int));
	 if (NULL == temp_disp_index) {
	   opal_output (1, "OUT OF MEMORY\n");
	   return OMPI_ERR_OUT_OF_RESOURCE;
	 }
	 for (i=0; i<entries_per_aggregator; i++){
	   temp_index = 
	     file_offsets_for_agg[sorted_file_offsets[i]].process_id;
	   displs_per_process[temp_index][temp_disp_index[temp_index]] =
	     memory_displacements[sorted_file_offsets[i]];
	   if (temp_disp_index[temp_index] < disp_index[temp_index]){
	     temp_disp_index[temp_index] += 1;
	   }
	   else{
	     printf("temp_disp_index[%d]: %d is greater than disp_index[%d]: %d\n",
		    temp_index, temp_disp_index[temp_index],
		    temp_index, disp_index[temp_index]);
	   }
	 }
	 if (NULL != temp_disp_index){
	   free(temp_disp_index);
	   temp_disp_index = NULL;
	 }

	 send_req = (MPI_Request *)
	   malloc (fh->f_procs_per_group * sizeof(MPI_Request));
	 if (NULL == send_req){
	   opal_output ( 1, "OUT OF MEMORY\n");
	   ret = OMPI_ERR_OUT_OF_RESOURCE;
	   goto exit;
	 }
 #if TIME_BREAKDOWN
	 start_rcomm_time = MPI_Wtime();
 #endif
	 for (i=0;i<fh->f_procs_per_group;i++){
	   ompi_datatype_create_hindexed(disp_index[i],
					 blocklen_per_process[i],
					 displs_per_process[i],
					 MPI_BYTE,
					 &sendtype[i]);
	   ompi_datatype_commit(&sendtype[i]); 
	   ret = MCA_PML_CALL (isend(global_buf,
				     1,
				     sendtype[i],
				     fh->f_procs_in_group[i],
				     123,
				     MCA_PML_BASE_SEND_STANDARD, 
				     fh->f_comm,
				     &send_req[i]));
	   if(OMPI_SUCCESS != ret){
	       goto exit;
	   }
	 }
 #if TIME_BREAKDOWN
	 end_rcomm_time = MPI_Wtime();
	 rcomm_time += end_rcomm_time - start_rcomm_time;
 #endif
       }

       /**********************************************************
	********* Scatter the Data from the readers **************
	*********************************************************/
       if (fh->f_flags & OMPIO_CONTIGUOUS_MEMORY) {
	 receive_buf = &((char*)buf)[position];
       }
       else if (bytes_received) {
	 /* allocate a receive buffer and copy the data that needs
	    to be received into it in case the data is non-contigous
	    in memory */
	 receive_buf = malloc (bytes_received);
	 if (NULL == receive_buf) {
	   opal_output (1, "OUT OF MEMORY\n");
	   return OMPI_ERR_OUT_OF_RESOURCE;
	 }
       }

 #if TIME_BREAKDOWN
       start_rcomm_time = MPI_Wtime();
 #endif
       recv_req = (MPI_Request *) malloc (sizeof (MPI_Request));
       if (NULL == recv_req){
	 opal_output (1, "OUT OF MEMORY\n");
	 ret = OMPI_ERR_OUT_OF_RESOURCE;
	 goto exit;
       }
       
       ret = MCA_PML_CALL(irecv(receive_buf,
				bytes_received,
				MPI_BYTE,
				fh->f_procs_in_group[fh->f_aggregator_index],
				123,
				fh->f_comm,
				recv_req));
       if (OMPI_SUCCESS != ret){
	 goto exit;
       }
       
       
       if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank){
	 ret = ompi_request_wait_all (fh->f_procs_per_group,
				    send_req,
				      MPI_STATUS_IGNORE);
	 if (OMPI_SUCCESS != ret){
	   goto exit;
	 }
       }
       
       ret = ompi_request_wait (recv_req, MPI_STATUS_IGNORE);
       if (OMPI_SUCCESS != ret){
	 goto exit;
       }
       position += bytes_received;
       
       /* If data is not contigous in memory, copy the data from the 
	  receive buffer into the buffer passed in */
       if (!(fh->f_flags & OMPIO_CONTIGUOUS_MEMORY)) {
	 OPAL_PTRDIFF_TYPE mem_address;
	 size_t remaining = 0;
	 size_t temp_position = 0;
	 
	 remaining = bytes_received;
	 
	 while (remaining) {
	   mem_address = (OPAL_PTRDIFF_TYPE)
	     (decoded_iov[iov_index].iov_base) + current_position;
	   
	   if (remaining >= 
	       (decoded_iov[iov_index].iov_len - current_position)) {
	     memcpy ((IOVBASE_TYPE *) mem_address,
		     receive_buf+temp_position,
		     decoded_iov[iov_index].iov_len - current_position);
	     remaining = remaining - 
	       (decoded_iov[iov_index].iov_len - current_position);
	     temp_position = temp_position +
	       (decoded_iov[iov_index].iov_len - current_position);
	     iov_index = iov_index + 1;
	     current_position = 0;
	   }
	   else {
	     memcpy ((IOVBASE_TYPE *) mem_address,
		     receive_buf+temp_position,
		     remaining);
	     current_position = current_position + remaining;
	     remaining = 0;
	   }
	 }
	 
	 if (NULL != receive_buf) {
	   free (receive_buf);
	 receive_buf = NULL;
	 }
       }
#if TIME_BREAKDOWN
       end_rcomm_time = MPI_Wtime();
       rcomm_time += end_rcomm_time - start_rcomm_time;
#endif
     
       if (NULL != recv_req){
	 free(recv_req);
	 recv_req = NULL;
       }
       if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank){
	 fh->f_num_of_io_entries = 0;
	 if (NULL != fh->f_io_array) {
	   free (fh->f_io_array);
	   fh->f_io_array = NULL;
	 }
	 if (NULL != global_buf) {
	   free (global_buf);
	   global_buf = NULL;
	 }
	 if (NULL != sendtype){
	   free(sendtype);
	   sendtype=NULL;
	 }
	 if (NULL != send_req){
	   free(send_req);
	   send_req = NULL;
	 }
	 if (NULL != sorted_file_offsets){
	   free(sorted_file_offsets);
	   sorted_file_offsets = NULL;
	 }
	 if (NULL != file_offsets_for_agg){
	   free(file_offsets_for_agg);
	   file_offsets_for_agg = NULL;
	 }
	 if (NULL != bytes_per_process){
	   free(bytes_per_process);
	   bytes_per_process =NULL;
	 }
	 if (NULL != memory_displacements){
	   free(memory_displacements);
	   memory_displacements= NULL;
	 }
       }
     }
     
 #if TIME_BREAKDOWN
     end_rexch = MPI_Wtime();
     read_exch += end_rexch - start_rexch;
     nentry.time[0] = read_time;
     nentry.time[1] = rcomm_time;
     nentry.time[2] = read_exch;
     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank)
       nentry.aggregator = 1;
     else
       nentry.aggregator = 0;
     nentry.nprocs_for_coll = mca_fcoll_dynamic_num_io_procs;
     if (!ompi_io_ompio_full_print_queue(READ_PRINT_QUEUE)){
       ompi_io_ompio_register_print_entry(READ_PRINT_QUEUE,
					  nentry);
     } 
 #endif

 exit:
     if (NULL != sorted) {
       free (sorted);
       sorted = NULL;
     }
     if (NULL != global_iov_array) {
       free (global_iov_array);
       global_iov_array = NULL;
     }
     if (NULL != fview_count) {
       free (fview_count);
       fview_count = NULL;
     }
     if (NULL != decoded_iov) {
       free (decoded_iov);
       decoded_iov = NULL;
     }
     if (NULL != local_iov_array){
       free(local_iov_array);
       local_iov_array=NULL;
     }
     
     if (NULL != displs) {
       free (displs);
       displs = NULL;
     }
     if (fh->f_procs_in_group[fh->f_aggregator_index] == fh->f_rank) {  

       if (NULL != disp_index){
	 free(disp_index);
	 disp_index = NULL;
       }
       
       for(l=0;l<fh->f_procs_per_group;l++){
	 if (NULL != blocklen_per_process[l]){
	   free(blocklen_per_process[l]);
	   blocklen_per_process[l] = NULL;
	 }
	 if (NULL != displs_per_process[l]){
	   free(displs_per_process[l]);
	   displs_per_process[l] = NULL;
	 }
       }
       if (NULL != blocklen_per_process){
	 free(blocklen_per_process);
	 blocklen_per_process = NULL;
       }
       if (NULL != displs_per_process){
	 free(displs_per_process);
	 displs_per_process = NULL;
       }

     }
     return ret;
 }


 static int read_heap_sort (local_io_array *io_array,
			    int num_entries,
			    int *sorted)
 {
     int i = 0;
     int j = 0;
     int left = 0;
     int right = 0;
     int largest = 0;
     int heap_size = num_entries - 1;
     int temp = 0;
     unsigned char done = 0;
     int* temp_arr = NULL;

     temp_arr = (int*)malloc(num_entries*sizeof(int));
     if (NULL == temp_arr) {
	 opal_output (1, "OUT OF MEMORY\n");
	 return OMPI_ERR_OUT_OF_RESOURCE;
     }
     temp_arr[0] = 0;
     for (i = 1; i < num_entries; ++i) {
	 temp_arr[i] = i;
     }
     /* num_entries can be a large no. so NO RECURSION */
     for (i = num_entries/2-1 ; i>=0 ; i--) {
	 done = 0;
	 j = i;
	 largest = j;

	 while (!done) {
	     left = j*2+1;
	     right = j*2+2;
	     if ((left <= heap_size) && 
		 (io_array[temp_arr[left]].offset > io_array[temp_arr[j]].offset)) {
		 largest = left;
	     }
	     else {
		 largest = j;
	     }
	     if ((right <= heap_size) && 
		 (io_array[temp_arr[right]].offset > 
		  io_array[temp_arr[largest]].offset)) {
		 largest = right;
	     }
	     if (largest != j) {
		 temp = temp_arr[largest];
		 temp_arr[largest] = temp_arr[j];
		 temp_arr[j] = temp;
		 j = largest;
	     }
	     else {
		 done = 1;
	     }
	 }
     }

     for (i = num_entries-1; i >=1; --i) {
	 temp = temp_arr[0];
	 temp_arr[0] = temp_arr[i];
	 temp_arr[i] = temp;            
	 heap_size--;            
	 done = 0;
	 j = 0;
	 largest = j;

	 while (!done) {
	     left =  j*2+1;
	     right = j*2+2;

	     if ((left <= heap_size) && 
		 (io_array[temp_arr[left]].offset > 
		  io_array[temp_arr[j]].offset)) {
		 largest = left;
	     }
	     else {
		 largest = j;
	     }
	     if ((right <= heap_size) && 
		 (io_array[temp_arr[right]].offset > 
		  io_array[temp_arr[largest]].offset)) {
		 largest = right;
	     }
	     if (largest != j) {
		 temp = temp_arr[largest];
		 temp_arr[largest] = temp_arr[j];
		 temp_arr[j] = temp;
		 j = largest;
	     }
	     else {
		 done = 1;
	     }
	 }
	 sorted[i] = temp_arr[i];
     }
     sorted[0] = temp_arr[0];

     if (NULL != temp_arr) {
	 free(temp_arr);
	 temp_arr = NULL;
     }
     return OMPI_SUCCESS;
 }