87 lines
3.3 KiB
Python
87 lines
3.3 KiB
Python
# Run test with:
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# torchrun --no_python --nproc_per_node=2 pytest -q -s tests/losses/test_cross_entropy_parallel_large_vocab.py
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import math
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import pytest
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import torch
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import torch.nn.functional as F
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from apex.transformer import parallel_state, tensor_parallel
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from flash_attn.losses.cross_entropy import CrossEntropyLoss
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is_sm8x = torch.cuda.get_device_capability("cuda")[0] >= 8
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@pytest.mark.parametrize(
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"dtype", [torch.float16, torch.float32] + ([torch.bfloat16] if is_sm8x else [])
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)
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# @pytest.mark.parametrize("dtype", [torch.float16])
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@pytest.mark.parametrize("inplace_backward", [False, True])
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# @pytest.mark.parametrize("inplace_backward", [False])
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@pytest.mark.parametrize("lse_square_scale", [0.0, 1e-2])
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# @pytest.mark.parametrize("lse_square_scale", [1e-2])
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@pytest.mark.parametrize("smoothing", [0.0, 0.9])
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# @pytest.mark.parametrize("smoothing", [0.0])
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@pytest.mark.parametrize("vocab_size", [256 * 1024]) # test vocab larger than 64k for split
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# @pytest.mark.parametrize("vocab_size", [50264]) # test vocab larger than 64k for split
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@pytest.mark.parametrize("world_size", [2])
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# @pytest.mark.parametrize("world_size", [2])
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def test_cross_entropy_loss_parallel(
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vocab_size, world_size, smoothing, lse_square_scale, inplace_backward, dtype
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):
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assert vocab_size % world_size == 0
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rtol, atol = (
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(1e-5, 1e-6)
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if dtype == torch.float32
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else ((1e-3, 1e-4) if dtype == torch.float16 else (1e-2, 3e-3))
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)
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if not torch.distributed.is_initialized():
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torch.distributed.init_process_group(backend="nccl", init_method="env://")
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partition_vocab_size = vocab_size // world_size
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device = f"cuda:{torch.distributed.get_rank()}"
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assert world_size <= torch.distributed.get_world_size()
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parallel_state.initialize_model_parallel(tensor_model_parallel_size_=world_size)
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rank = parallel_state.get_tensor_model_parallel_rank()
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# set seed
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torch.random.manual_seed(0)
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batch_size = 8
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seqlen = 128
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x_pt = (
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torch.randn(batch_size * seqlen, vocab_size, device=device, dtype=dtype) * 10
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).requires_grad_()
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x = (
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tensor_parallel.scatter_to_tensor_model_parallel_region(x_pt)
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.detach()
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.clone()
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.requires_grad_()
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)
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y = torch.randint(0, vocab_size, (batch_size * seqlen,), dtype=torch.long, device=device)
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y[torch.randperm(batch_size * seqlen)[:10]] = -100
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model_pt = torch.nn.CrossEntropyLoss(label_smoothing=smoothing, reduction="none")
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model = CrossEntropyLoss(
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label_smoothing=smoothing,
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reduction="none",
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lse_square_scale=lse_square_scale,
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inplace_backward=inplace_backward,
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process_group=parallel_state.get_tensor_model_parallel_group(),
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)
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out = model(x, y)
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out_pt = model_pt(x_pt.float(), y)
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if lse_square_scale > 0.0:
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lse_pt = torch.logsumexp(x_pt.float(), dim=-1)
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out_pt += lse_square_scale * lse_pt.square()
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out_pt.masked_fill_(y == -100, 0.0)
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assert torch.allclose(out, out_pt, rtol=1e-5, atol=1e-6)
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g = torch.randn_like(out)
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out_pt.backward(g)
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out.backward(g)
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assert torch.allclose(
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x.grad,
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x_pt.grad[:, (rank * partition_vocab_size) : (rank + 1) * partition_vocab_size],
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rtol=rtol,
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atol=atol,
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)
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parallel_state.destroy_model_parallel()
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