pytorch/test/test_decomp.py
Horace He 70d80fb424 Fixed type promotion semantics for native_batch_norm and native_layer_norm (#77407)
Originally, when these were written, they simply used the naive strategy of "upcast all inputs to floats, and downcast all inputs back". In addition to being... not quite what the kernels did, they also didn't capture some additional semantics. Namely, that the norms (except for layer norm on CPU! cc: @ngimel) return fp32 for the mean and rstd values.

Also, folks didn't like that I wrote `native_layer_norm` in terms of `native_batch_norm`. Which is fair - so I refactored the common logic into a `normalize` function.

cc: @jansel / @bertmaher , who've been looking at lowering layer norm/batch norm.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/77407
Approved by: https://github.com/bertmaher
2022-05-19 17:11:47 +00:00

506 lines
18 KiB
Python

# Owner(s): ["module: primTorch"]
from collections import defaultdict
from torch import Tensor
import torch.autograd
from torch.utils._python_dispatch import enable_torch_dispatch_mode
from torch._decomp import decomposition_table
from torch.utils._pytree import tree_map, tree_flatten, tree_unflatten
from torch.testing._internal.logging_tensor import no_dispatch
from torch.testing._internal.common_utils import (
is_iterable_of_tensors,
TestCase,
skipIfCrossRef,
suppress_warnings,
TEST_WITH_ASAN,
run_tests,
)
from torch.testing._internal.common_device_type import (
onlyNativeDeviceTypes,
ops,
instantiate_device_type_tests,
)
from torch.testing._internal.common_methods_invocations import op_db
import itertools
import functools
from functools import partial
import unittest
aten = torch.ops.aten
# TODO: this isn't going to work with non-aten namespaces
def overload_to_aten_name(overload):
return overload._schema.name.split("::")[1]
# All operators that can have decomp tests
decomposition_names = {overload_to_aten_name(k) for k in decomposition_table}
_decomp_test_ops = [
op
for op in op_db
if op.aten_name in decomposition_names
or op.aten_backward_name in decomposition_names
]
def diff_arg(arg, requires_grad=True):
def is_differentiable_arg(arg):
if requires_grad:
return arg.requires_grad
else:
return arg.is_floating_point() or arg.is_complex()
if is_iterable_of_tensors(arg):
if all([is_differentiable_arg(a) for a in arg]):
return True
if all([not is_differentiable_arg(a) for a in arg]):
return False
raise RuntimeError("NYI: The test runner can't handle this")
return isinstance(arg, Tensor) and is_differentiable_arg(arg)
# Version of autograd.grad with some differences:
# - pytree inputs is allowed (but leaves of the pytree have to all
# be tensors)
# - if an input is not used as part of derivatives, we will return a
# zero-filled tensor for the result
def _autograd_grad(
outputs, inputs, grad_outputs=None, retain_graph=False, create_graph=True
):
inputs, inputs_spec = tree_flatten(inputs)
diff_inputs = tuple(inp for inp in inputs if inp.requires_grad)
if grad_outputs is None:
diff_outputs = tuple(out for out in outputs if out.requires_grad)
else:
diff_grad_outputs = [
(out, go) for out, go in zip(outputs, grad_outputs) if out.requires_grad
]
if len(diff_grad_outputs) == 0:
diff_outputs, grad_outputs = (), ()
else:
diff_outputs, grad_outputs = zip(*diff_grad_outputs)
grad_inputs = torch.autograd.grad(
diff_outputs,
diff_inputs,
grad_outputs,
retain_graph=retain_graph,
create_graph=create_graph,
allow_unused=True,
)
result = []
grad_inputs_iter = iter(grad_inputs)
for inp in inputs:
if inp.requires_grad:
grad_input = next(grad_inputs_iter)
if grad_input is None:
result.append(torch.zeros_like(inp))
else:
result.append(grad_input)
else:
result.append(torch.zeros_like(inp))
return tree_unflatten(result, inputs_spec)
def _as_tuple(val):
if isinstance(val, tuple):
return val
return (val,)
def ref_vjp_no_create(f, *primals):
result = f(*primals)
def wrapped(cotangents):
return _autograd_grad(
_as_tuple(result), primals, _as_tuple(cotangents), create_graph=False
)
return result, wrapped
dtype_precisions = {
torch.float16: (0.001, 1e-5),
torch.bfloat16: (0.016, 1e-4),
torch.float32: (1.3e-6, 1e-5),
torch.float64: (1e-7, 1e-7),
torch.complex32: (0.001, 1e-5),
torch.complex64: (1.3e-6, 1e-5),
torch.complex128: (1e-7, 1e-7),
}
# Returns the "default" rtol and atol for comparing scalars or
# tensors of the given dtypes.
def _getDefaultRtolAndAtol(dtype0, dtype1):
rtol = max(
dtype_precisions.get(dtype0, (0, 0))[0], dtype_precisions.get(dtype1, (0, 0))[0]
)
atol = max(
dtype_precisions.get(dtype0, (0, 0))[1], dtype_precisions.get(dtype1, (0, 0))[1]
)
return rtol, atol
def op_assert_ref(test_case, op, test_dtype, orig, decomp, ref, args, kwargs):
assert orig.dtype == decomp.dtype, f"Operation: {op}"
if orig.numel() == 0 or decomp.numel() == 0:
assert orig.numel() == decomp.numel()
return
assert orig.shape == decomp.shape, f"Operation: {op}"
tol_table = {
(torch.bfloat16, torch.ops.aten.native_layer_norm.default): 1e-5,
(torch.float16, torch.ops.aten.native_layer_norm.default): 1e-5,
(torch.bfloat16, torch.ops.aten.native_batch_norm.default): 1e-5,
(torch.float16, torch.ops.aten.native_batch_norm.default): 1e-5,
}
if ref.is_floating_point():
orig_diff = (orig - ref).abs().max()
decomp_diff = (decomp - ref).abs().max()
atol = tol_table.get((test_dtype, op), 1e-7)
if decomp_diff > orig_diff + atol:
raise RuntimeError(
f"Difference from float64 is larger with decomposition {op.__name__}"
f" than original. Original max diff: {orig_diff}, Decomp max diff: {decomp_diff}\n"
f"atol = {atol}\n"
f"args = {args}\n"
f"kwargs = {kwargs}"
)
else:
test_case.assertEqual(
orig, decomp, msg=f"{op.__name__}\nargs = {args}\nkwargs = {kwargs}"
)
def op_assert_equal(test_case, op, test_dtype, orig, decomp, args, kwargs):
test_case.assertEqual(
orig.dtype, decomp.dtype, f"Operation: {op}, orig.dtype: {orig.dtype}, decomp.dtype: {decomp.dtype}, {args}, {kwargs}")
# Before adding an entry to this table, make sure your decomposition is right :)
tol_table = {
# Due to strange epsilon behaviors, see https://github.com/pytorch/pytorch/issues/73161
(torch.float32, torch.ops.aten.native_layer_norm.default): (1e-3, 1e-3),
(torch.float32, torch.ops.aten.native_layer_norm_backward.default): (
1e-3,
1e-3,
),
}
if (test_dtype, op) in tol_table:
rtol, atol = tol_table[(decomp.dtype, op)]
else:
rtol, atol = _getDefaultRtolAndAtol(orig.dtype, decomp.dtype)
test_case.assertEqual(orig, decomp, rtol=rtol, atol=atol, msg=f"{op.__name__}\nargs = {args}\nkwargs = {kwargs}")
# Given f, returns an f' such that:
# - f' takes only positional arguments
# - All arguments to f' are floating-point Tensors
# - All outputs of f' are floating-point Tensors
def normalize_op_input_output2(
f, args, kwargs, output_process_fn_grad=None, requires_grad=True
):
flat_args, args_spec = tree_flatten(args)
diff_argnums = tuple(
i
for i, arg in enumerate(flat_args)
if diff_arg(arg, requires_grad=requires_grad)
)
assert len(diff_argnums) > 0
primals = tuple(flat_args[i] for i in diff_argnums)
@functools.wraps(f)
def wrapped(*primals):
_args = list(flat_args)
for num, arg in zip(diff_argnums, primals):
_args[num] = arg
_args = tree_unflatten(_args, args_spec)
result = f(*_args, **kwargs)
if output_process_fn_grad is not None:
result = output_process_fn_grad(result)
if isinstance(result, tuple):
# TODO: Remove the following hack for namedtuples
result = tuple(result)
result = tuple(
r
for r in result
if isinstance(r, Tensor) and (r.is_floating_point() or r.is_complex())
)
assert len(result) > 0
return result
return wrapped, primals
# NB: This also upcasts dtype arguments
def upcast_tensor(func, x, dtype=torch.float32):
# Some functions take a dtype as argument, so we need to
# manually change that dtype in order to run it with a
# higher precision
dtype_arg_table = {
torch.ops.aten._softmax_backward_data.default,
torch.ops.aten._log_softmax_backward_data.default,
}
if isinstance(x, Tensor) and x.dtype.is_floating_point:
return x.to(dtype=dtype)
elif (
isinstance(x, torch.dtype)
and func in dtype_arg_table
and x in [torch.float16, torch.bfloat16]
):
return torch.float64
else:
return x
def normalize_op_input_output(f, sample, requires_grad=True):
args = tuple([sample.input] + list(sample.args))
return normalize_op_input_output2(
f,
args,
sample.kwargs,
sample.output_process_fn_grad,
requires_grad=requires_grad,
)
CROSS_REF_EXCLUDE_SET = {
# CUBLAS_STATUS_NOT_SUPPORTED when calling
# `cublasGemmStridedBatchedExFix(handle, opa, opb, (int)m, (int)n, (int)k,
# (void*)&falpha, a, CUDA_R_16BF, (int)lda, stridea, b, CUDA_R_16BF,
# (int)ldb, strideb, (void*)&fbeta, c, CUDA_R_16BF, (int)ldc, stridec,
# (int)num_batches, CUDA_R_32F, CUBLAS_GEMM_DEFAULT_TENSOR_OP)`
("cuda", torch.bfloat16, "nn.functional.bilinear"),
# randomness
("cuda", torch.float16, "nn.functional.dropout"),
("cuda", torch.bfloat16, "nn.functional.dropout"),
("cuda", torch.float64, "nn.functional.dropout"),
("cuda", torch.float32, "nn.functional.dropout"),
# decomp has problem even with opmath
# doesn't work
("cuda", torch.bfloat16, "nn.functional.embedding"),
}
all_decomposed = set()
all_called = defaultdict(int)
# Helpful snippet for testing coverage
"""
import atexit
def check_coverage():
print("missing coverage:")
print("\n".join(map(str, decomposition_table.keys() - all_decomposed)))
atexit.register(check_coverage)
"""
# Helpful snippet for Horace to create his google sheet :)
"""
import atexit
def dump_ops():
with open('run_ops.txt', 'w') as f, open('count_ops.txt', 'w') as g:
for op, count in sorted(all_called.items(), key=lambda x: x[0].__name__):
f.write(f'{op.__name__}\n')
g.write(f'{count}\n')
with open('run_decompositions.txt', 'w') as f:
for op in sorted([i.__name__ for i in all_decomposed]):
f.write(f'{op}\n')
atexit.register(dump_ops)
"""
def any_unsupported(args, kwargs):
def test_unsupported(t):
if type(t) is torch.Tensor or type(t) is torch.nn.Parameter:
# These are all things that we haven't coded decompositions
# to handle correctly. Maybe they should.
return any([
t.is_sparse_csr, t.is_sparse, t.is_mkldnn, t.is_quantized,
t.is_nested, torch._is_functional_tensor(t),
])
elif torch.overrides.is_tensor_like(t):
# Decompositions will generally change the behavior of Tensor-like
# subclasses, so bypass tests in this case too
return True
else:
return False
flat_args, _ = tree_flatten(args)
flat_kwargs, _ = tree_flatten(kwargs)
return any(test_unsupported(x) for x in itertools.chain(flat_args, flat_kwargs))
class TestDecomp(TestCase):
longMessage = True
# NB: This actually overlaps with test_comprehensive, but it only
# runs on things that are definitely decomposed so it's a lot faster
# to run
@unittest.skipIf(TEST_WITH_ASAN, "Skipped under ASAN")
@onlyNativeDeviceTypes
@skipIfCrossRef
@suppress_warnings
@ops(_decomp_test_ops)
def test_quick(self, device, dtype, op):
self.do_cross_ref(device, dtype, op, run_all=False)
@unittest.skipIf(TEST_WITH_ASAN, "Skipped under ASAN")
@onlyNativeDeviceTypes
@skipIfCrossRef
@suppress_warnings
@ops(op_db)
def test_comprehensive(self, device, dtype, op):
self.do_cross_ref(device, dtype, op, run_all=True)
def do_cross_ref(self, device, dtype, op, *, run_all):
if (torch.device(device).type, dtype, op.name) in CROSS_REF_EXCLUDE_SET or (
None,
dtype,
op.name,
) in CROSS_REF_EXCLUDE_SET:
self.skipTest(f"{op.name} in {dtype} not supported")
test_dtype = dtype
# We check the correctness of each decomposition right after running it.
# So, when we encounter a decomposition, we run the function normally, and
# then run the decomposition, and ensure they're identical.
called = set()
decomposed = set()
saved_precision = self.precision
saved_rel_tol = self.rel_tol
class DecompCrossRefMode(torch.Tensor):
@classmethod
def __torch_dispatch__(cls, func, types, args=(), kwargs=None):
with no_dispatch():
return cls._torch_dispatch(func, types, args, kwargs)
@classmethod
def _torch_dispatch(cls, func, types, args=(), kwargs=None):
self.precision = saved_precision
self.rel_tol = saved_rel_tol
called.add(func)
all_called[func] += 1
# Stuff we shouldn't bother testing
# (TODO: remove detach from the decomp table?)
if func not in decomposition_table or func in [
torch.ops.aten.detach.default
] or any_unsupported(args, kwargs):
return func(*args, **kwargs)
decomposed.add(func)
all_decomposed.add(func)
# We take 2 main strategies for verifying correctness/numerical stability of decompositions
# The first one is simply tolerance checking between decomp_out and pytorch_out
# However, for fp16/bf16 and reductions, this becomes very
# finicky, as there are not many guarantees we can make.
# So, for fp16/bf16, we instead compare the difference of
# {decomp_out, pytorch_out_64} and {pytorch_out,
# pytorch_out_64}. In other words, we compare how far the
# decomposition and pytorch are from the "ground truth" (i.e.
# fp64). If the decomposition results in more error, we error
decomposition = decomposition_table[func]
do_relative_check = test_dtype in [torch.float16, torch.bfloat16]
real_out_unflat = func(*args, **kwargs)
real_out, _ = tree_flatten(real_out_unflat)
decomp_out, _ = tree_flatten(decomposition(*args, **kwargs))
assert len(real_out) == len(decomp_out)
if do_relative_check:
upcast = partial(upcast_tensor, func, dtype=torch.float64)
real_out_double, _ = tree_flatten(
func(*tree_map(upcast, args), **tree_map(upcast, kwargs))
)
for orig, decomp, ref in zip(real_out, decomp_out, real_out_double):
if orig is None:
assert decomp is None
continue
op_assert_ref(self, func, test_dtype, orig, decomp, ref, args, kwargs)
else:
for orig, decomp in zip(real_out, decomp_out):
if orig is None:
assert decomp is None
continue
op_assert_equal(self, func, test_dtype, orig, decomp, args, kwargs)
return real_out_unflat
requires_grad = (
op.supports_autograd
and dtype in op.supported_backward_dtypes(torch.device(device).type)
# TODO: OpInfo really ought to error out for this case, but it's
# not exercised in test_ops_gradients atm. The problem is not
# complex32 per-se (which is supported by data movement only ops)
# but that when we do backwards we expect other ops like add to work
and not dtype == torch.complex32
)
samples = op.sample_inputs(device, test_dtype, requires_grad=requires_grad)
def check_decomposed(aten_name):
self.assertTrue(
any(overload_to_aten_name(c) == aten_name for c in decomposed),
msg=f"aten.{aten_name} was not decomposed, saw calls for: "
+ ", ".join(map(str, list(called))),
)
aten_name = op.decomp_aten_name or op.aten_name
func = op.get_op()
for sample_input in samples:
if requires_grad:
fn, primals = normalize_op_input_output(func, sample_input)
primals = tree_map(
lambda x: x if isinstance(x, torch.Tensor) else x, primals
)
# Once https://github.com/pytorch/pytorch/pull/75965/ I can
# store the called list on the mode object instance and no
# explicit clearing is necessary as I will create a fresh mode
# for each region
decomposed.clear()
with enable_torch_dispatch_mode(DecompCrossRefMode):
decomp_out, decomp_vjp_fn = ref_vjp_no_create(fn, *primals)
if aten_name in decomposition_names:
check_decomposed(aten_name)
if op.aten_backward_name in decomposition_names or run_all:
cotangents = tree_map(lambda x: torch.randn_like(x), decomp_out)
decomposed.clear()
with enable_torch_dispatch_mode(DecompCrossRefMode):
decomp_vjp_fn(cotangents)
if not run_all:
check_decomposed(op.aten_backward_name)
elif aten_name in decomposition_names or run_all:
args = [sample_input.input] + list(sample_input.args)
kwargs = sample_input.kwargs
decomposed.clear()
with enable_torch_dispatch_mode(DecompCrossRefMode):
func(*args, **kwargs)
if not run_all:
check_decomposed(aten_name)
else:
assert op.supports_autograd
self.skipTest(
"only backwards is decomposed, but dtype doesn't support AD"
)
instantiate_device_type_tests(TestDecomp, globals())
if __name__ == "__main__":
run_tests()