File size: 20,164 Bytes
3eb682b
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import numpy as np
import io
import os
import time
from collections import defaultdict, deque
import datetime

import torch
import torch.distributed as dist

def optimizer_to(optim, device):
    for param in optim.state.values():
        # Not sure there are any global tensors in the state dict
        if isinstance(param, torch.Tensor):
            param.data = param.data.to(device)
            if param._grad is not None:
                param._grad.data = param._grad.data.to(device)
        elif isinstance(param, dict):
            for subparam in param.values():
                if isinstance(subparam, torch.Tensor):
                    subparam.data = subparam.data.to(device)
                    if subparam._grad is not None:
                        subparam._grad.data = subparam._grad.data.to(device)
                        

class SmoothedValue(object):
    """Track a series of values and provide access to smoothed values over a
    window or the global series average.
    """

    def __init__(self, window_size=20, fmt=None):
        if fmt is None:
            fmt = "{median:.4f} ({global_avg:.4f})"
        self.deque = deque(maxlen=window_size)
        self.total = 0.0
        self.count = 0
        self.fmt = fmt

    def update(self, value, n=1):
        self.deque.append(value)
        self.count += n
        self.total += value * n

    def synchronize_between_processes(self):
        """
        Warning: does not synchronize the deque!
        """
        if not is_dist_avail_and_initialized():
            return
        t = torch.tensor([self.count, self.total], dtype=torch.float64, device='cuda')
        dist.barrier()
        dist.all_reduce(t)
        t = t.tolist()
        self.count = int(t[0])
        self.total = t[1]

    @property
    def median(self):
        d = torch.tensor(list(self.deque))
        return d.median().item()

    @property
    def avg(self):
        d = torch.tensor(list(self.deque), dtype=torch.float32)
        return d.mean().item()

    @property
    def global_avg(self):
        return self.total / self.count

    @property
    def max(self):
        return max(self.deque)

    @property
    def value(self):
        return self.deque[-1]

    def __str__(self):
        return self.fmt.format(
            median=self.median,
            avg=self.avg,
            global_avg=self.global_avg,
            max=self.max,
            value=self.value)


class MetricLogger(object):
    def __init__(self, delimiter="\t", accelerator=None):
        self.meters = defaultdict(SmoothedValue)
        self.delimiter = delimiter
        self.accelerator = accelerator

    def update(self, **kwargs):
        for k, v in kwargs.items():
            if isinstance(v, torch.Tensor):
                v = v.item()
            assert isinstance(v, (float, int))
            self.meters[k].update(v)

    def __getattr__(self, attr):
        if attr in self.meters:
            return self.meters[attr]
        if attr in self.__dict__:
            return self.__dict__[attr]
        raise AttributeError("'{}' object has no attribute '{}'".format(
            type(self).__name__, attr))

    def __str__(self):
        loss_str = []
        for name, meter in self.meters.items():
            loss_str.append(
                "{}: {}".format(name, str(meter))
            )
        return self.delimiter.join(loss_str)

    def global_avg(self):
        loss_str = []
        for name, meter in self.meters.items():
            loss_str.append(
                "{}: {:.4f}".format(name, meter.global_avg)
            )
        return self.delimiter.join(loss_str)    
    
    def synchronize_between_processes(self):
        for meter in self.meters.values():
            meter.synchronize_between_processes()

    def add_meter(self, name, meter):
        self.meters[name] = meter

    def log_every(self, iterable, print_freq, header=None):
        i = 0
        if not header:
            header = ''
        start_time = time.time()
        end = time.time()
        iter_time = SmoothedValue(fmt='{avg:.4f}')
        data_time = SmoothedValue(fmt='{avg:.4f}')
        space_fmt = ':' + str(len(str(len(iterable)))) + 'd'
        log_msg = [
            header,
            '[{0' + space_fmt + '}/{1}]',
            'eta: {eta}',
            '{meters}',
            'time: {time}',
            'data: {data}'
        ]
        if torch.cuda.is_available():
            log_msg.append('max mem: {memory:.0f}')
        log_msg = self.delimiter.join(log_msg)
        MB = 1024.0 * 1024.0

        if self.accelerator is not None:
            print_func = self.accelerator.print
        else:
            print_func = print
        for obj in iterable:
            data_time.update(time.time() - end)
            yield obj
            iter_time.update(time.time() - end)
            if i % print_freq == 0 or i == len(iterable) - 1:
                eta_seconds = iter_time.global_avg * (len(iterable) - i)
                eta_string = str(datetime.timedelta(seconds=int(eta_seconds)))
                if torch.cuda.is_available():
                    print_func(log_msg.format(
                        i, len(iterable), eta=eta_string,
                        meters=str(self),
                        time=str(iter_time), data=str(data_time),
                        memory=torch.cuda.max_memory_allocated() / MB))
                else:
                    print_func(log_msg.format(
                        i, len(iterable), eta=eta_string,
                        meters=str(self),
                        time=str(iter_time), data=str(data_time)))
            i += 1
            end = time.time()
        total_time = time.time() - start_time
        total_time_str = str(datetime.timedelta(seconds=int(total_time)))
        print_func('{} Total time: {} ({:.4f} s / it)'.format(
            header, total_time_str, total_time / len(iterable)))
        


class AttrDict(dict):
    def __init__(self, *args, **kwargs):
        super(AttrDict, self).__init__(*args, **kwargs)
        self.__dict__ = self


def compute_acc(logits, label, reduction='mean'):
    ret = (torch.argmax(logits, dim=1) == label).float()
    if reduction == 'none':
        return ret.detach()
    elif reduction == 'mean':
        return ret.mean().item()

def compute_n_params(model, return_str=True):
    tot = 0
    for p in model.parameters():
        w = 1
        for x in p.shape:
            w *= x
        tot += w
    if return_str:
        if tot >= 1e6:
            return '{:.1f}M'.format(tot / 1e6)
        else:
            return '{:.1f}K'.format(tot / 1e3)
    else:
        return tot

def setup_for_distributed(is_master):
    """
    This function disables printing when not in master process
    """
    import builtins as __builtin__
    builtin_print = __builtin__.print

    def print(*args, **kwargs):
        force = kwargs.pop('force', False)
        if is_master or force:
            builtin_print(*args, **kwargs)

    __builtin__.print = print


def is_dist_avail_and_initialized():
    if not dist.is_available():
        return False
    if not dist.is_initialized():
        return False
    return True


def get_world_size():
    if not is_dist_avail_and_initialized():
        return 1
    return dist.get_world_size()


def get_rank():
    if not is_dist_avail_and_initialized():
        return 0
    return dist.get_rank()


def is_main_process():
    return get_rank() == 0


def save_on_master(*args, **kwargs):
    if is_main_process():
        torch.save(*args, **kwargs)


def init_distributed_mode(args):
    if 'RANK' in os.environ and 'WORLD_SIZE' in os.environ:
        args.rank = int(os.environ["RANK"])
        args.world_size = int(os.environ['WORLD_SIZE'])
        args.gpu = int(os.environ['LOCAL_RANK'])
    elif 'SLURM_PROCID' in os.environ:
        args.rank = int(os.environ['SLURM_PROCID'])
        args.gpu = args.rank % torch.cuda.device_count()
        print(args.gpu, os.environ['SLURM_LOCALID'], os.environ['SLURM_JOB_NODELIST'], os.environ['SLURM_STEP_GPUS'])
    else:
        print('Not using distributed mode')
        args.distributed = False
        return

    args.distributed = True

    torch.cuda.set_device(args.gpu)
    args.dist_backend = 'nccl'
    print('world_size', args.world_size, 'gpu', args.gpu, 'dist_url:', args.dist_url)
    print('| distributed init (rank {}): {}'.format(
        args.rank, args.dist_url), flush=True)
    torch.distributed.init_process_group(backend=args.dist_backend, init_method=args.dist_url,
                                         world_size=args.world_size, rank=args.rank)
    print("init")
    torch.distributed.barrier()
    setup_for_distributed(args.rank == 0)


def init_distributed_mode_multinodes(args):
    import hostlist
    if 'RANK' in os.environ and 'WORLD_SIZE' in os.environ:
        args.rank = int(os.environ["RANK"])
        args.world_size = int(os.environ['WORLD_SIZE'])
        args.gpu = int(os.environ['LOCAL_RANK'])
    elif 'SLURM_PROCID' in os.environ:
        args.rank = int(os.environ['SLURM_PROCID'])
        args.gpu = args.rank % torch.cuda.device_count()
        print('slurm')
    else:
        print('Not using distributed mode')
        args.distributed = False
        return

    args.distributed = True
    # print(args.gpu, os.environ['SLURM_PROCID'], os.environ['SLURM_LOCALID'], os.environ['SLURM_JOB_NODELIST'], os.environ['SLURM_STEP_GPUS'])
    hostnames = hostlist.expand_hostlist(os.environ['SLURM_JOB_NODELIST'])
    os.environ['MASTER_ADDR'] = hostnames[0]
    gpu_ids = os.environ['SLURM_STEP_GPUS'].split(",")
    # os.environ['MASTER_PORT'] = str(12345 + int(min(gpu_ids))) # to avoid port conflict on the same node

    print(os.environ['MASTER_ADDR'], os.environ['MASTER_PORT'])

    torch.cuda.set_device(args.gpu)
    args.dist_backend = 'nccl'
    args.dist_url = 'tcp://'+os.environ['MASTER_ADDR']+':'+os.environ['MASTER_PORT']

    print('world_size', args.world_size, 'gpu', args.gpu)
    print('| distributed init (rank {}): {}'.format(
        args.rank, args.dist_url), flush=True)

    

    torch.distributed.init_process_group(backend=args.dist_backend, init_method=args.dist_url,
                                         world_size=args.world_size, rank=args.rank)
    # torch.distributed.barrier()
    # setup_for_distributed(args.rank == 0)


def init_distributed_mode_multinodes_jz(args):
    import hostlist
    if args.jean_zay:
        hostnames = hostlist.expand_hostlist(os.environ['SLURM_JOB_NODELIST'])
        os.environ['MASTER_ADDR'] = hostnames[0]

        print(os.environ['MASTER_ADDR'], os.environ['MASTER_PORT'], os.environ['SLURM_PROCID'], os.environ['SLURM_NTASKS'], os.environ['SLURM_LOCALID'])
        args.gpu = int(os.environ['SLURM_LOCALID'])
        args.rank = int(os.environ['SLURM_PROCID'])
        args.world_size = int(os.environ['SLURM_NTASKS'])
        args.dist_url = 'env://'+os.environ['MASTER_ADDR']+':'+os.environ['MASTER_PORT']
        # args.dist_url = 'env://'
        print('jean zay')
    elif 'RANK' in os.environ and 'WORLD_SIZE' in os.environ:
        args.rank = int(os.environ["RANK"])
        args.world_size = int(os.environ['WORLD_SIZE'])
        args.gpu = int(os.environ['LOCAL_RANK'])
    elif 'SLURM_PROCID' in os.environ:
        args.rank = int(os.environ['SLURM_PROCID'])
        args.gpu = args.rank % torch.cuda.device_count()
        print('slurm')
    else:
        print('Not using distributed mode')
        args.distributed = False
        return

    args.distributed = True

    torch.cuda.set_device(args.gpu)
    args.dist_backend = 'nccl'
    print('world_size', args.world_size, 'gpu', args.gpu, 'rank', args.rank)
    print('| distributed init (rank {}): {}'.format(
        args.rank, args.dist_url), flush=True)
    torch.distributed.init_process_group(backend=args.dist_backend, init_method=args.dist_url,
                                         world_size=args.world_size, rank=args.rank)


    torch.distributed.barrier()
    setup_for_distributed(args.rank == 0)










# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
"""
This file contains primitives for multi-gpu communication.
This is useful when doing distributed training.
"""

import functools
import logging
import numpy as np
import pickle
import torch
import torch.distributed as dist

import torch

_LOCAL_PROCESS_GROUP = None
"""
A torch process group which only includes processes that on the same machine as the current process.
This variable is set when processes are spawned by `launch()` in "engine/launch.py".
"""


def get_world_size() -> int:
    if not dist.is_available():
        return 1
    if not dist.is_initialized():
        return 1
    return dist.get_world_size()


def get_rank() -> int:
    if not dist.is_available():
        return 0
    if not dist.is_initialized():
        return 0
    return dist.get_rank()


def get_local_rank() -> int:
    """
    Returns:
        The rank of the current process within the local (per-machine) process group.
    """
    if not dist.is_available():
        return 0
    if not dist.is_initialized():
        return 0
    assert _LOCAL_PROCESS_GROUP is not None
    return dist.get_rank(group=_LOCAL_PROCESS_GROUP)


def get_local_size() -> int:
    """
    Returns:
        The size of the per-machine process group,
        i.e. the number of processes per machine.
    """
    if not dist.is_available():
        return 1
    if not dist.is_initialized():
        return 1
    return dist.get_world_size(group=_LOCAL_PROCESS_GROUP)


def is_main_process() -> bool:
    return get_rank() == 0


def synchronize():
    """
    Helper function to synchronize (barrier) among all processes when
    using distributed training
    """
    if not dist.is_available():
        return
    if not dist.is_initialized():
        return
    world_size = dist.get_world_size()
    if world_size == 1:
        return
    dist.barrier()


@functools.lru_cache()
def _get_global_gloo_group():
    """
    Return a process group based on gloo backend, containing all the ranks
    The result is cached.
    """
    if dist.get_backend() == "nccl":
        return dist.new_group(backend="gloo")
    else:
        return dist.group.WORLD


def _serialize_to_tensor(data, group):
    backend = dist.get_backend(group)
    assert backend in ["gloo", "nccl"]
    device = torch.device("cpu" if backend == "gloo" else "cuda")

    buffer = pickle.dumps(data)
    if len(buffer) > 1024 ** 3:
        logger = logging.getLogger(__name__)
        logger.warning(
            "Rank {} trying to all-gather {:.2f} GB of data on device {}".format(
                get_rank(), len(buffer) / (1024 ** 3), device
            )
        )
    storage = torch.ByteStorage.from_buffer(buffer)
    tensor = torch.ByteTensor(storage).to(device=device)
    return tensor


def _pad_to_largest_tensor(tensor, group):
    """
    Returns:
        list[int]: size of the tensor, on each rank
        Tensor: padded tensor that has the max size
    """
    world_size = dist.get_world_size(group=group)
    assert (
        world_size >= 1
    ), "comm.gather/all_gather must be called from ranks within the given group!"
    local_size = torch.tensor(
        [tensor.numel()], dtype=torch.int64, device=tensor.device)
    size_list = [
        torch.zeros([1], dtype=torch.int64, device=tensor.device)
        for _ in range(world_size)
    ]
    dist.all_gather(size_list, local_size, group=group)
    size_list = [int(size.item()) for size in size_list]

    max_size = max(size_list)

    # we pad the tensor because torch all_gather does not support
    # gathering tensors of different shapes
    if local_size != max_size:
        padding = torch.zeros(
            (max_size - local_size,), dtype=torch.uint8, device=tensor.device
        )
        tensor = torch.cat((tensor, padding), dim=0)
    return size_list, tensor


def all_gather(data, group=None):
    """
    Run all_gather on arbitrary picklable data (not necessarily tensors).
    Args:
        data: any picklable object
        group: a torch process group. By default, will use a group which
            contains all ranks on gloo backend.
    Returns:
        list[data]: list of data gathered from each rank
    """
    if get_world_size() == 1:
        return [data]
    if group is None:
        group = _get_global_gloo_group()
    if dist.get_world_size(group) == 1:
        return [data]

    tensor = _serialize_to_tensor(data, group)

    size_list, tensor = _pad_to_largest_tensor(tensor, group)
    max_size = max(size_list)

    # receiving Tensor from all ranks
    tensor_list = [
        torch.empty((max_size,), dtype=torch.uint8, device=tensor.device)
        for _ in size_list
    ]
    dist.all_gather(tensor_list, tensor, group=group)

    data_list = []
    for size, tensor in zip(size_list, tensor_list):
        buffer = tensor.cpu().numpy().tobytes()[:size]
        data_list.append(pickle.loads(buffer))

    return data_list


def gather(data, dst=0, group=None):
    """
    Run gather on arbitrary picklable data (not necessarily tensors).
    Args:
        data: any picklable object
        dst (int): destination rank
        group: a torch process group. By default, will use a group which
            contains all ranks on gloo backend.
    Returns:
        list[data]: on dst, a list of data gathered from each rank. Otherwise,
            an empty list.
    """
    if get_world_size() == 1:
        return [data]
    if group is None:
        group = _get_global_gloo_group()
    if dist.get_world_size(group=group) == 1:
        return [data]
    rank = dist.get_rank(group=group)

    tensor = _serialize_to_tensor(data, group)
    size_list, tensor = _pad_to_largest_tensor(tensor, group)

    # receiving Tensor from all ranks
    if rank == dst:
        max_size = max(size_list)
        tensor_list = [
            torch.empty((max_size,), dtype=torch.uint8, device=tensor.device)
            for _ in size_list
        ]
        dist.gather(tensor, tensor_list, dst=dst, group=group)

        data_list = []
        for size, tensor in zip(size_list, tensor_list):
            buffer = tensor.cpu().numpy().tobytes()[:size]
            data_list.append(pickle.loads(buffer))
        return data_list
    else:
        dist.gather(tensor, [], dst=dst, group=group)
        return []


def shared_random_seed():
    """
    Returns:
        int: a random number that is the same across all workers.
            If workers need a shared RNG, they can use this shared seed to
            create one.
    All workers must call this function, otherwise it will deadlock.
    """
    ints = np.random.randint(2 ** 31)
    all_ints = all_gather(ints)
    return all_ints[0]



def reduce_dict(input_dict, average=True):
    """
    Reduce the values in the dictionary from all processes so that process with rank
    0 has the reduced results.
    Args:
        input_dict (dict): inputs to be reduced. (values not necessarily tensors).
        average (bool): whether to do average or sum
    Returns:
        a dict with the same keys as input_dict, after reduction.
    """

    world_size = get_world_size()
    if world_size < 2:
        return input_dict

    with torch.no_grad():

        # Convert to CUDA Tensor for dist.reduce()
        input_dict_cuda_vals = {}
        for k, v in input_dict.items():
            if type(v) == torch.Tensor:
                input_dict_cuda_vals[k] = v.to('cuda')
            else:
                input_dict_cuda_vals[k] = torch.tensor(v, device='cuda')

        names = []
        values = []
        for k, v in sorted(input_dict_cuda_vals.items()):
            names.append(k)
            values.append(v)
        values = torch.stack(values, dim=0)
        dist.reduce(values, dst=0) # reduce to gpu 0

        if dist.get_rank() == 0 and average:
            # only main process gets accumulated, so only divide by
            # world_size in this case
            values /= world_size
        reduced_dict = {k: v for k, v in zip(names, values)}
    return reduced_dict