File size: 4,444 Bytes
f8f62f3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import os

import torch
import torch.distributed as dist

try:
    import horovod.torch as hvd
except ImportError:
    hvd = None


def is_global_master(args):
    return args.rank == 0


def is_local_master(args):
    return args.local_rank == 0


def is_master(args, local=False):
    return is_local_master(args) if local else is_global_master(args)


def is_using_horovod():
    # NOTE w/ horovod run, OMPI vars should be set, but w/ SLURM PMI vars will be set
    # Differentiating between horovod and DDP use via SLURM may not be possible, so horovod arg still required...
    ompi_vars = ["OMPI_COMM_WORLD_RANK", "OMPI_COMM_WORLD_SIZE"]
    pmi_vars = ["PMI_RANK", "PMI_SIZE"]
    if all([var in os.environ for var in ompi_vars]) or all([var in os.environ for var in pmi_vars]):
        return True
    else:
        return False


def is_using_distributed():
    if 'WORLD_SIZE' in os.environ:
        return int(os.environ['WORLD_SIZE']) > 1
    if 'SLURM_NTASKS' in os.environ:
        return int(os.environ['SLURM_NTASKS']) > 1
    return False


def world_info_from_env():
    local_rank = 0
    for v in ('LOCAL_RANK', 'MPI_LOCALRANKID', 'SLURM_LOCALID', 'OMPI_COMM_WORLD_LOCAL_RANK'):
        if v in os.environ:
            local_rank = int(os.environ[v])
            break
    global_rank = 0
    for v in ('RANK', 'PMI_RANK', 'SLURM_PROCID', 'OMPI_COMM_WORLD_RANK'):
        if v in os.environ:
            global_rank = int(os.environ[v])
            break
    world_size = 1
    for v in ('WORLD_SIZE', 'PMI_SIZE', 'SLURM_NTASKS', 'OMPI_COMM_WORLD_SIZE'):
        if v in os.environ:
            world_size = int(os.environ[v])
            break

    return local_rank, global_rank, world_size


def init_distributed_device(args):
    # Distributed training = training on more than one GPU.
    # Works in both single and multi-node scenarios.
    args.distributed = False
    args.world_size = 1
    args.rank = 0  # global rank
    args.local_rank = 0
    if args.horovod:
        assert hvd is not None, "Horovod is not installed"
        hvd.init()
        args.local_rank = int(hvd.local_rank())
        args.rank = hvd.rank()
        args.world_size = hvd.size()
        args.distributed = True
        os.environ['LOCAL_RANK'] = str(args.local_rank)
        os.environ['RANK'] = str(args.rank)
        os.environ['WORLD_SIZE'] = str(args.world_size)
    elif is_using_distributed():
        if 'SLURM_PROCID' in os.environ:
            # DDP via SLURM
            args.local_rank, args.rank, args.world_size = world_info_from_env()
            # SLURM var -> torch.distributed vars in case needed
            os.environ['LOCAL_RANK'] = str(args.local_rank)
            os.environ['RANK'] = str(args.rank)
            os.environ['WORLD_SIZE'] = str(args.world_size)
            torch.distributed.init_process_group(
                backend=args.dist_backend,
                init_method=args.dist_url,
                world_size=args.world_size,
                rank=args.rank,
            )
        else:
            # DDP via torchrun, torch.distributed.launch
            args.local_rank, _, _ = world_info_from_env()
            torch.distributed.init_process_group(
                backend=args.dist_backend,
                init_method=args.dist_url)
            args.world_size = torch.distributed.get_world_size()
            args.rank = torch.distributed.get_rank()
        args.distributed = True

    if torch.cuda.is_available():
        if args.distributed and not args.no_set_device_rank:
            device = 'cuda:%d' % args.local_rank
        else:
            device = 'cuda:0'
        torch.cuda.set_device(device)
    else:
        device = 'cpu'
    args.device = device
    device = torch.device(device)
    return device


def broadcast_object(args, obj, src=0):
    # broadcast a pickle-able python object from rank-0 to all ranks
    if args.horovod:
        return hvd.broadcast_object(obj, root_rank=src)
    else:
        if args.rank == src:
            objects = [obj]
        else:
            objects = [None]
        dist.broadcast_object_list(objects, src=src)
        return objects[0]


def all_gather_object(args, obj, dst=0):
    # gather a pickle-able python object across all ranks
    if args.horovod:
        return hvd.allgather_object(obj)
    else:
        objects = [None for _ in range(args.world_size)]
        dist.all_gather_object(objects, obj)
        return objects