summaryrefslogtreecommitdiffstats
path: root/src/H5mpi.c
blob: 11b0b7bcdd78c3bfbcfd16ba483b16ad36510423 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Purpose:     Common MPI routines
 *
 */

#include "H5private.h"   /* Generic Functions                        */
#include "H5Eprivate.h"  /* Error handling                           */
#include "H5MMprivate.h" /* Memory Management                        */

#ifdef H5_HAVE_PARALLEL

/****************/
/* Local Macros */
/****************/
#define TWO_GIG_LIMIT INT32_MAX
#ifndef H5_MAX_MPI_COUNT
#define H5_MAX_MPI_COUNT (1 << 30)
#endif

/*******************/
/* Local Variables */
/*******************/
static hsize_t bigio_count_g = H5_MAX_MPI_COUNT;

/*-------------------------------------------------------------------------
 * Function:  H5_mpi_set_bigio_count
 *
 * Purpose:   Allow us to programmatically change the switch point
 *            when we utilize derived datatypes.  This is of
 *            particular interest for allowing nightly testing
 *
 * Return:    The current/previous value of bigio_count_g.
 *
 * Programmer: Richard Warren,  March 10, 2017
 *
 *-------------------------------------------------------------------------
 */
hsize_t
H5_mpi_set_bigio_count(hsize_t new_count)
{
    hsize_t orig_count = bigio_count_g;

    if ((new_count > 0) && (new_count < (hsize_t)TWO_GIG_LIMIT)) {
        bigio_count_g = new_count;
    }
    return orig_count;
} /* end H5_mpi_set_bigio_count() */

/*-------------------------------------------------------------------------
 * Function:  H5_mpi_get_bigio_count
 *
 * Purpose:   Allow other HDF5 library functions to access
 *            the current value for bigio_count_g.
 *
 * Return:    The current/previous value of bigio_count_g.
 *
 * Programmer: Richard Warren,  October 7, 2019
 *
 *-------------------------------------------------------------------------
 */
H5_ATTR_PURE hsize_t
H5_mpi_get_bigio_count(void)
{
    return bigio_count_g;
}

/*-------------------------------------------------------------------------
 * Function:    H5_mpi_comm_dup
 *
 * Purpose:     Duplicate an MPI communicator.
 *
 *              Does not duplicate MPI_COMM_NULL. Instead, comm_new will
 *              be set to MPI_COMM_NULL directly.
 *
 *              The new communicator is returned via the comm_new pointer.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpi_comm_dup(MPI_Comm comm, MPI_Comm *comm_new)
{
    herr_t   ret_value = SUCCEED;
    MPI_Comm comm_dup  = MPI_COMM_NULL;
    int      mpi_code;

    FUNC_ENTER_NOAPI(FAIL)

    /* Check arguments */
    if (!comm_new)
        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "comm_new cannot be NULL")

    /* Handle MPI_COMM_NULL separately */
    if (MPI_COMM_NULL == comm) {
        /* Don't duplicate MPI_COMM_NULL since that's an error in MPI */
        comm_dup = MPI_COMM_NULL;
    }
    else {

        /* Duplicate the MPI communicator */
        if (MPI_SUCCESS != (mpi_code = MPI_Comm_dup(comm, &comm_dup)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Comm_dup failed", mpi_code)

        /* Set MPI_ERRORS_RETURN on comm_dup so that MPI failures are not fatal,
         * and return codes can be checked and handled.
         */
        if (MPI_SUCCESS != (mpi_code = MPI_Comm_set_errhandler(comm_dup, MPI_ERRORS_RETURN)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Errhandler_set failed", mpi_code)
    }

    /* Copy the new communicator to the return argument */
    *comm_new = comm_dup;

done:
    if (FAIL == ret_value) {
        /* need to free anything created here */
        if (MPI_COMM_NULL != comm_dup)
            MPI_Comm_free(&comm_dup);
    }

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpi_comm_dup() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpi_info_dup
 *
 * Purpose:     Duplicate an MPI info.
 *
 *              If the info object is MPI_INFO_NULL, no duplicate
 *              is made but the same value assigned to the new info object
 *              handle.
 *
 *              The new info is returned via the info_new pointer.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpi_info_dup(MPI_Info info, MPI_Info *info_new)
{
    herr_t   ret_value = SUCCEED;
    MPI_Info info_dup  = MPI_INFO_NULL;
    int      mpi_code;

    FUNC_ENTER_NOAPI(FAIL)

    /* Check arguments */
    if (!info_new)
        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "info_new cannot be NULL")

    /* Duplicate the MPI info */
    if (info == MPI_INFO_NULL) {
        /* Don't duplicate MPI_INFO_NULL. Just copy it. */
        info_dup = MPI_INFO_NULL;
    }
    else {
        /* Duplicate the info */
        if (MPI_SUCCESS != (mpi_code = MPI_Info_dup(info, &info_dup)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Info_dup failed", mpi_code)
    }

    /* Copy the new info to the return argument */
    *info_new = info_dup;

done:
    if (FAIL == ret_value) {
        /* need to free anything created here */
        if (MPI_INFO_NULL != info_dup)
            MPI_Info_free(&info_dup);
    }

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpi_info_dup() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpi_comm_free
 *
 * Purpose:     Free an MPI communicator.
 *
 *              If comm is MPI_COMM_NULL this call does nothing.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpi_comm_free(MPI_Comm *comm)
{
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    /* Check arguments */
    if (!comm)
        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "comm pointer cannot be NULL")

    /* Free the communicator */
    if (MPI_COMM_WORLD != *comm && MPI_COMM_NULL != *comm)
        MPI_Comm_free(comm);

    *comm = MPI_COMM_NULL;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* End H5_mpi_comm_free() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpi_info_free
 *
 * Purpose:     Free the MPI info.
 *
 *              If info is MPI_INFO_NULL this call does nothing.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpi_info_free(MPI_Info *info)
{
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    /* Check arguments */
    if (!info)
        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "info pointer cannot be NULL")

    /* Free the info */
    if (MPI_INFO_NULL != *info)
        MPI_Info_free(info);

    *info = MPI_INFO_NULL;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* End H5_mpi_info_free() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpi_comm_cmp
 *
 * Purpose:     Compares two MPI communicators.
 *
 *              Note that passing MPI_COMM_NULL to this function will not
 *              throw errors, unlike MPI_Comm_compare().
 *
 *              We consider MPI communicators to be the "same" when the
 *              groups are identical. We don't care about the context
 *              since that will always be different as we call MPI_Comm_dup
 *              when we store the communicator in the fapl.
 *
 *              The out parameter is a value like strcmp. The value is
 *              undefined when the return value is FAIL.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpi_comm_cmp(MPI_Comm comm1, MPI_Comm comm2, int *result)
{
    int    mpi_code;
    int    mpi_result = MPI_IDENT;
    herr_t ret_value  = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    /* Check arguments */
    if (!result)
        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "result cannot be NULL")

    /* Set out parameter to something reasonable in case something goes wrong */
    *result = 0;

    /* Can't pass MPI_COMM_NULL to MPI_Comm_compare() so we have to handle
     * it in special cases.
     *
     * MPI_Comm can either be an integer type or a pointer. We cast them
     * to intptr_t so we can compare them with < and > when needed.
     */
    if (MPI_COMM_NULL == comm1 && MPI_COMM_NULL == comm2) {
        /* Special case of both communicators being MPI_COMM_NULL */
        *result = 0;
    }
    else if (MPI_COMM_NULL == comm1 || MPI_COMM_NULL == comm2) {

        /* Special case of one communicator being MPI_COMM_NULL */
        *result = (intptr_t)comm1 < (intptr_t)comm2 ? -1 : 1;
    }
    else {

        /* Normal communicator compare */

        /* Compare the MPI communicators */
        if (MPI_SUCCESS != (mpi_code = MPI_Comm_compare(comm1, comm2, &mpi_result)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Comm_compare failed", mpi_code)

        /* Set the result */
        if (MPI_IDENT == mpi_result || MPI_CONGRUENT == mpi_result)
            *result = 0;
        else
            *result = (intptr_t)comm1 < (intptr_t)comm2 ? -1 : 1;
    }

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpi_comm_cmp() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpi_info_cmp
 *
 * Purpose:     Compares two MPI info objects.
 *
 *              For our purposes, two mpi info objects are the "same" if
 *              they contain the same key-value pairs or are both
 *              MPI_INFO_NULL.
 *
 *              The out parameter is a value like strcmp. The value is
 *              undefined when the return value is FAIL.
 *
 * Return:      SUCCEED/FAIL
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpi_info_cmp(MPI_Info info1, MPI_Info info2, int *result)
{
    hbool_t same      = FALSE;
    char   *key       = NULL;
    char   *value1    = NULL;
    char   *value2    = NULL;
    herr_t  ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    /* Check arguments */
    if (!result)
        HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "result cannot be NULL")

    /* Check for MPI_INFO_NULL */
    if (MPI_INFO_NULL == info1 && MPI_INFO_NULL == info2) {
        /* Special case of both info objects being MPI_INFO_NULL */
        same = TRUE;
    }
    else if (MPI_INFO_NULL == info1 || MPI_INFO_NULL == info2) {

        /* Special case of one info object being MPI_INFO_NULL */
        same = FALSE;
    }
    else {
        int mpi_code;
        int nkeys_1;
        int nkeys_2;

        /* Check if the number of keys is the same */
        if (MPI_SUCCESS != (mpi_code = MPI_Info_get_nkeys(info1, &nkeys_1)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Info_get_nkeys failed", mpi_code)
        if (MPI_SUCCESS != (mpi_code = MPI_Info_get_nkeys(info2, &nkeys_2)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Info_get_nkeys failed", mpi_code)

        if (nkeys_1 != nkeys_2)
            same = FALSE;
        else if (0 == nkeys_1 && 0 == nkeys_2)
            same = TRUE;
        else {
            int i;
            int flag1 = -1;
            int flag2 = -1;

            /* Allocate buffers for iteration */
            if (NULL == (key = (char *)H5MM_malloc(MPI_MAX_INFO_KEY * sizeof(char))))
                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
            if (NULL == (value1 = (char *)H5MM_malloc(MPI_MAX_INFO_VAL * sizeof(char))))
                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
            if (NULL == (value2 = (char *)H5MM_malloc(MPI_MAX_INFO_VAL * sizeof(char))))
                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")

            /* Iterate over the keys, comparing them */
            for (i = 0; i < nkeys_1; i++) {

                same = TRUE;

                /* Memset the buffers to zero */
                memset(key, 0, MPI_MAX_INFO_KEY);
                memset(value1, 0, MPI_MAX_INFO_VAL);
                memset(value2, 0, MPI_MAX_INFO_VAL);

                /* Get the nth key */
                if (MPI_SUCCESS != (mpi_code = MPI_Info_get_nthkey(info1, i, key)))
                    HMPI_GOTO_ERROR(FAIL, "MPI_Info_get_nthkey failed", mpi_code)

                /* Get the values */
                if (MPI_SUCCESS != (mpi_code = MPI_Info_get(info1, key, MPI_MAX_INFO_VAL, value1, &flag1)))
                    HMPI_GOTO_ERROR(FAIL, "MPI_Info_get failed", mpi_code)
                if (MPI_SUCCESS != (mpi_code = MPI_Info_get(info2, key, MPI_MAX_INFO_VAL, value2, &flag2)))
                    HMPI_GOTO_ERROR(FAIL, "MPI_Info_get failed", mpi_code)

                /* Compare values and flags */
                if (!flag1 || !flag2 || memcmp(value1, value2, MPI_MAX_INFO_VAL)) {
                    same = FALSE;
                    break;
                }

            } /* end for */
        }     /* end else */
    }         /* end else */

    /* Set the output value
     *
     * MPI_Info can either be an integer type or a pointer. We cast them
     * to intptr_t so we can compare them with < and > when needed.
     */
    if (same)
        *result = 0;
    else
        *result = (intptr_t)info1 < (intptr_t)info2 ? -1 : 1;

done:
    if (key)
        H5MM_xfree(key);
    if (value1)
        H5MM_xfree(value1);
    if (value2)
        H5MM_xfree(value2);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpi_info_cmp() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpio_create_large_type
 *
 * Purpose:     Create a large datatype of size larger than what a 32 bit integer
 *              can hold.
 *
 * Return:      Non-negative on success, negative on failure.
 *
 *              *new_type    the new datatype created
 *
 * Programmer:  Mohamad Chaarawi
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpio_create_large_type(hsize_t num_elements, MPI_Aint stride_bytes, MPI_Datatype old_type,
                          MPI_Datatype *new_type)
{
    int          num_big_types;   /* num times the 2G datatype will be repeated */
    int          remaining_bytes; /* the number of bytes left that can be held in an int value */
    hsize_t      leftover;
    int          block_len[2];
    int          mpi_code; /* MPI return code */
    MPI_Datatype inner_type, outer_type, leftover_type, type[2];
    MPI_Aint     disp[2], old_extent;
    herr_t       ret_value = SUCCEED; /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    /* Calculate how many Big MPI datatypes are needed to represent the buffer */
    num_big_types = (int)(num_elements / bigio_count_g);
    leftover      = (hsize_t)num_elements - (hsize_t)num_big_types * bigio_count_g;
    H5_CHECKED_ASSIGN(remaining_bytes, int, leftover, hsize_t);

    /* Create a contiguous datatype of size equal to the largest
     * number that a 32 bit integer can hold x size of old type.
     * If the displacement is 0, then the type is contiguous, otherwise
     * use type_hvector to create the type with the displacement provided
     */
    if (0 == stride_bytes) {
        if (MPI_SUCCESS != (mpi_code = MPI_Type_contiguous((int)bigio_count_g, old_type, &inner_type)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
    } /* end if */
    else if (MPI_SUCCESS !=
             (mpi_code = MPI_Type_create_hvector((int)bigio_count_g, 1, stride_bytes, old_type, &inner_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hvector failed", mpi_code)

    /* Create a contiguous datatype of the buffer (minus the remaining < 2GB part)
     * If a stride is present, use hvector type
     */
    if (0 == stride_bytes) {
        if (MPI_SUCCESS != (mpi_code = MPI_Type_contiguous(num_big_types, inner_type, &outer_type)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
    } /* end if */
    else if (MPI_SUCCESS !=
             (mpi_code = MPI_Type_create_hvector(num_big_types, 1, stride_bytes, inner_type, &outer_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hvector failed", mpi_code)

    MPI_Type_free(&inner_type);

    /* If there is a remaining part create a contiguous/vector datatype and then
     * use a struct datatype to encapsulate everything.
     */
    if (remaining_bytes) {
        if (stride_bytes == 0) {
            if (MPI_SUCCESS != (mpi_code = MPI_Type_contiguous(remaining_bytes, old_type, &leftover_type)))
                HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
        } /* end if */
        else if (MPI_SUCCESS != (mpi_code = MPI_Type_create_hvector(
                                     (int)(num_elements - (hsize_t)num_big_types * bigio_count_g), 1,
                                     stride_bytes, old_type, &leftover_type)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hvector failed", mpi_code)

        /* As of version 4.0, OpenMPI now turns off MPI-1 API calls by default,
         * so we're using the MPI-2 version even though we don't need the lb
         * value.
         */
        {
            MPI_Aint unused_lb_arg;
            MPI_Type_get_extent(old_type, &unused_lb_arg, &old_extent);
        }

        /* Set up the arguments for MPI_Type_create_struct() */
        type[0]      = outer_type;
        type[1]      = leftover_type;
        block_len[0] = 1;
        block_len[1] = 1;
        disp[0]      = 0;
        disp[1]      = (old_extent + stride_bytes) * num_big_types * (MPI_Aint)bigio_count_g;

        if (MPI_SUCCESS != (mpi_code = MPI_Type_create_struct(2, block_len, disp, type, new_type)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_struct failed", mpi_code)

        MPI_Type_free(&outer_type);
        MPI_Type_free(&leftover_type);
    } /* end if */
    else
        /* There are no remaining bytes so just set the new type to
         * the outer type created */
        *new_type = outer_type;

    if (MPI_SUCCESS != (mpi_code = MPI_Type_commit(new_type)))
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_commit failed", mpi_code)

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpio_create_large_type() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpio_gatherv_alloc
 *
 * Purpose:     A wrapper around MPI_(All)gatherv that performs allocation
 *              of the receive buffer on the caller's behalf. This
 *              routine's parameters are as follows:
 *
 *              `send_buf` - The buffer that data will be sent from for
 *                           the calling MPI rank. Analogous to
 *                           MPI_(All)gatherv's `sendbuf` parameter.
 *
 *              `send_count` - The number of `send_type` elements in the
 *                             send buffer. Analogous to MPI_(All)gatherv's
 *                             `sendcount` parameter.
 *
 *              `send_type` - The MPI Datatype of the elements in the send
 *                            buffer. Analogous to MPI_(All)gatherv's
 *                            `sendtype` parameter.
 *
 *              `recv_counts` - An array containing the number of elements
 *                              to be received from each MPI rank.
 *                              Analogous to MPI_(All)gatherv's `recvcount`
 *                              parameter.
 *
 *              `displacements` - An array containing the displacements
 *                                in the receive buffer where data from
 *                                each MPI rank should be placed. Analogous
 *                                to MPI_(All)gatherv's `displs` parameter.
 *
 *              `recv_type` - The MPI Datatype of the elements in the
 *                            receive buffer. Analogous to
 *                            MPI_(All)gatherv's `recvtype` parameter.
 *
 *              `allgather` - Specifies whether the gather operation to be
 *                            performed should be MPI_Allgatherv (TRUE) or
 *                            MPI_Gatherv (FALSE).
 *
 *              `root` - For MPI_Gatherv operations, specifies the rank
 *                       that will receive the data sent by other ranks.
 *                       Analogous to MPI_Gatherv's `root` parameter. For
 *                       MPI_Allgatherv operations, this parameter is
 *                       ignored.
 *
 *              `comm` - Specifies the MPI Communicator for the operation.
 *                       Analogous to MPI_(All)gatherv's `comm` parameter.
 *
 *              `mpi_rank` - Specifies the calling rank's rank value, as
 *                           obtained by calling MPI_Comm_rank on the
 *                           MPI Communicator `comm`.
 *
 *              `mpi_size` - Specifies the MPI Communicator size, as
 *                           obtained by calling MPI_Comm_size on the
 *                           MPI Communicator `comm`.
 *
 *              `out_buf` - Resulting buffer that is allocated and
 *                          returned to the caller after data has been
 *                          gathered into it. Returned only to the rank
 *                          specified by `root` for MPI_Gatherv
 *                          operations, or to all ranks for
 *                          MPI_Allgatherv operations.
 *
 *              `out_buf_num_entries` - The number of elements in the
 *                                      resulting buffer, in terms of
 *                                      the MPI Datatype provided for
 *                                      `recv_type`.
 *
 * Notes:       This routine is collective across `comm`.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpio_gatherv_alloc(void *send_buf, int send_count, MPI_Datatype send_type, const int recv_counts[],
                      const int displacements[], MPI_Datatype recv_type, hbool_t allgather, int root,
                      MPI_Comm comm, int mpi_rank, int mpi_size, void **out_buf, size_t *out_buf_num_entries)
{
    size_t recv_buf_num_entries = 0;
    void  *recv_buf             = NULL;
#if H5_CHECK_MPI_VERSION(3, 0)
    MPI_Count type_lb;
    MPI_Count type_extent;
#else
    MPI_Aint type_lb;
    MPI_Aint type_extent;
#endif
    int    mpi_code;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    assert(send_buf || send_count == 0);
    if (allgather || (mpi_rank == root))
        assert(out_buf && out_buf_num_entries);

        /* Retrieve the extent of the MPI Datatype being used */
#if H5_CHECK_MPI_VERSION(3, 0)
    if (MPI_SUCCESS != (mpi_code = MPI_Type_get_extent_x(recv_type, &type_lb, &type_extent)))
#else
    if (MPI_SUCCESS != (mpi_code = MPI_Type_get_extent(recv_type, &type_lb, &type_extent)))
#endif
        HMPI_GOTO_ERROR(FAIL, "MPI_Type_get_extent(_x) failed", mpi_code)

    if (type_extent < 0)
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "MPI recv_type had a negative extent")

    /*
     * Calculate the total size of the buffer being
     * returned and allocate it
     */
    if (allgather || (mpi_rank == root)) {
        size_t i;
        size_t buf_size;

        for (i = 0, recv_buf_num_entries = 0; i < (size_t)mpi_size; i++)
            recv_buf_num_entries += (size_t)recv_counts[i];
        buf_size = recv_buf_num_entries * (size_t)type_extent;

        /* If our buffer size is 0, there's nothing to do */
        if (buf_size == 0)
            HGOTO_DONE(SUCCEED)

        if (NULL == (recv_buf = H5MM_malloc(buf_size)))
            /* Push an error, but still participate in collective gather operation */
            HDONE_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "couldn't allocate receive buffer")
    }

    /* Perform gather operation */
    if (allgather) {
        if (MPI_SUCCESS != (mpi_code = MPI_Allgatherv(send_buf, send_count, send_type, recv_buf, recv_counts,
                                                      displacements, recv_type, comm)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Allgatherv failed", mpi_code)
    }
    else {
        if (MPI_SUCCESS != (mpi_code = MPI_Gatherv(send_buf, send_count, send_type, recv_buf, recv_counts,
                                                   displacements, recv_type, root, comm)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Gatherv failed", mpi_code)
    }

    if (allgather || (mpi_rank == root)) {
        *out_buf             = recv_buf;
        *out_buf_num_entries = recv_buf_num_entries;
    }

done:
    if (ret_value < 0) {
        if (recv_buf)
            H5MM_free(recv_buf);
    }

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpio_gatherv_alloc() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpio_gatherv_alloc_simple
 *
 * Purpose:     A slightly simplified interface to H5_mpio_gatherv_alloc
 *              which calculates the receive counts and receive buffer
 *              displacements for the caller.
 *
 * Notes:       This routine is collective across `comm`.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpio_gatherv_alloc_simple(void *send_buf, int send_count, MPI_Datatype send_type, MPI_Datatype recv_type,
                             hbool_t allgather, int root, MPI_Comm comm, int mpi_rank, int mpi_size,
                             void **out_buf, size_t *out_buf_num_entries)
{
    int   *recv_counts_disps_array = NULL;
    int    mpi_code;
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    assert(send_buf || send_count == 0);
    if (allgather || (mpi_rank == root))
        assert(out_buf && out_buf_num_entries);

    /*
     * Allocate array to store the receive counts of each rank, as well as
     * the displacements into the final array where each rank will place
     * their data. The first half of the array contains the receive counts
     * (in rank order), while the latter half contains the displacements
     * (also in rank order).
     */
    if (allgather || (mpi_rank == root)) {
        if (NULL ==
            (recv_counts_disps_array = H5MM_malloc(2 * (size_t)mpi_size * sizeof(*recv_counts_disps_array))))
            /* Push an error, but still participate in collective gather operation */
            HDONE_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL,
                        "couldn't allocate receive counts and displacements array")
    }

    /* Collect each rank's send count to interested ranks */
    if (allgather) {
        if (MPI_SUCCESS !=
            (mpi_code = MPI_Allgather(&send_count, 1, MPI_INT, recv_counts_disps_array, 1, MPI_INT, comm)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Allgather failed", mpi_code)
    }
    else {
        if (MPI_SUCCESS !=
            (mpi_code = MPI_Gather(&send_count, 1, MPI_INT, recv_counts_disps_array, 1, MPI_INT, root, comm)))
            HMPI_GOTO_ERROR(FAIL, "MPI_Gather failed", mpi_code)
    }

    /* Set the displacements into the receive buffer for the gather operation */
    if (allgather || (mpi_rank == root)) {
        size_t i;
        int   *displacements_ptr;

        displacements_ptr = &recv_counts_disps_array[mpi_size];

        *displacements_ptr = 0;
        for (i = 1; i < (size_t)mpi_size; i++)
            displacements_ptr[i] = displacements_ptr[i - 1] + recv_counts_disps_array[i - 1];
    }

    /* Perform gather operation */
    if (H5_mpio_gatherv_alloc(send_buf, send_count, send_type, recv_counts_disps_array,
                              &recv_counts_disps_array[mpi_size], recv_type, allgather, root, comm, mpi_rank,
                              mpi_size, out_buf, out_buf_num_entries) < 0)
        HGOTO_ERROR(H5E_LIB, H5E_CANTGATHER, FAIL, "can't gather data")

done:
    if (recv_counts_disps_array)
        H5MM_free(recv_counts_disps_array);

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpio_gatherv_alloc_simple() */

/*-------------------------------------------------------------------------
 * Function:    H5_mpio_get_file_sync_required
 *
 * Purpose:     Retrieve the MPI hint indicating whether the data written
 *              by the MPI ROMIO driver is immediately visible to all MPI
 *              ranks.
 *
 * Notes:       This routine is designed for supporting UnifyFS that needs
 *              MPI_File_sync in order to make the written data available
 *              to all ranks.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 * Programmer:  Houjun Tang,  April 7, 2022
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5_mpio_get_file_sync_required(MPI_File fh, hbool_t *file_sync_required)
{
    MPI_Info info_used;
    int      flag;
    char    *sync_env_var;
    char     value[MPI_MAX_INFO_VAL];
    herr_t   ret_value = SUCCEED;

    FUNC_ENTER_NOAPI(FAIL)

    assert(file_sync_required);

    *file_sync_required = FALSE;

    if (MPI_SUCCESS != MPI_File_get_info(fh, &info_used))
        HGOTO_ERROR(H5E_LIB, H5E_CANTGET, FAIL, "can't get MPI info")

    if (MPI_SUCCESS !=
        MPI_Info_get(info_used, "romio_visibility_immediate", MPI_MAX_INFO_VAL - 1, value, &flag))
        HGOTO_ERROR(H5E_LIB, H5E_CANTGET, FAIL, "can't get MPI info")

    if (flag && !HDstrcmp(value, "false"))
        *file_sync_required = TRUE;

    if (MPI_SUCCESS != MPI_Info_free(&info_used))
        HGOTO_ERROR(H5E_LIB, H5E_CANTFREE, FAIL, "can't free MPI info")

    /* Force setting the flag via env variable (temp solution before the flag is implemented in MPI) */
    sync_env_var = HDgetenv("HDF5_DO_MPI_FILE_SYNC");
    if (sync_env_var && (!HDstrcmp(sync_env_var, "TRUE") || !HDstrcmp(sync_env_var, "1")))
        *file_sync_required = TRUE;
    if (sync_env_var && (!HDstrcmp(sync_env_var, "FALSE") || !HDstrcmp(sync_env_var, "0")))
        *file_sync_required = FALSE;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5_mpio_get_file_sync_required() */
#endif /* H5_HAVE_PARALLEL */