apex / tests /L0 /run_transformer /test_cross_entropy.py
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import logging
from typing import Tuple
import torch
import torch.nn.functional as F
from torch.testing._internal import common_utils
logging.getLogger("torch").setLevel(logging.WARNING)
from apex.transformer import parallel_state
from apex.transformer import tensor_parallel
from apex.transformer.tensor_parallel import cross_entropy
from apex.transformer.testing.commons import set_random_seed, IdentityLayer
from apex.transformer.testing.distributed_test_base import NcclDistributedTestBase
from apex.transformer.testing.distributed_test_base import UccDistributedTestBase
logging.getLogger("apex").setLevel(logging.WARNING)
def torch_cross_entropy(
batch_size: int, seq_length: int, vocab_size: int, logits_scale: float, seed: int, label_smoothing: float = 0.0
) -> Tuple[torch.Tensor, torch.Tensor]:
set_random_seed(seed)
identity = IdentityLayer(
(batch_size, seq_length, vocab_size), scale=logits_scale
).cuda()
logits = identity()
target = torch.cuda.LongTensor(size=(batch_size, seq_length)).random_(0, vocab_size)
loss = (
F.cross_entropy(
logits.view(-1, logits.size()[-1]), target.view(-1), reduction="none", label_smoothing=label_smoothing
)
.view_as(target)
.mean()
)
loss.backward()
return loss, identity.weight.grad
def tensor_sharded_cross_entropy(
batch_size, seq_length, vocab_size, logits_scale, seed, label_smoothing=0.0
):
set_random_seed(seed)
identity = IdentityLayer(
(batch_size, seq_length, vocab_size), scale=logits_scale
).cuda()
logits = identity()
logits_parallel = tensor_parallel.scatter_to_tensor_model_parallel_region(logits)
target = torch.cuda.LongTensor(size=(batch_size, seq_length)).random_(0, vocab_size)
logits_parallel_ = logits_parallel.clone().detach()
loss = cross_entropy.vocab_parallel_cross_entropy(logits_parallel, target, label_smoothing=label_smoothing).mean()
loss.backward()
# check for mutation
assert torch.equal(logits_parallel_, logits_parallel)
return loss, identity.weight.grad
class VocabParallelCrossEntropyTestBase:
def test_cross_entropy(self):
batch_size, sequence_length, vocab_size_per_partition = 13, 17, 11
logits_scale = 1000.0
seed = 1234
for tensor_model_parallel_world_size in range(1, self.world_size + 1):
if self.world_size % tensor_model_parallel_world_size:
continue
parallel_state.initialize_model_parallel(
tensor_model_parallel_size_=tensor_model_parallel_world_size,
)
vocab_size = vocab_size_per_partition * tensor_model_parallel_world_size
loss_torch, grad_torch = torch_cross_entropy(
batch_size, sequence_length, vocab_size, logits_scale, seed
)
(
loss_tensor_parallel,
grad_tensor_parallel,
) = tensor_sharded_cross_entropy(
batch_size, sequence_length, vocab_size, logits_scale, seed
)
self.assertEqual(
loss_torch, loss_tensor_parallel,
msg=f"tensor_model_parallel_size: {tensor_model_parallel_world_size}",
)
self.assertEqual(
grad_torch, grad_tensor_parallel,
msg=f"tensor_model_parallel_size: {tensor_model_parallel_world_size}",
)
parallel_state.destroy_model_parallel()
class NcclVocabParallelCrossEntropyTest(VocabParallelCrossEntropyTestBase, NcclDistributedTestBase): pass
class UccVocabParallelCrossEntropyTest(VocabParallelCrossEntropyTestBase, UccDistributedTestBase): pass
if __name__ == "__main__":
common_utils.run_tests()