Files
pytorch/test/distributed/_tensor/test_op_strategy.py
Wanchao Liang cfc227ad43 [reland][dtensor] move DTensor to public namespace (#134203)
reland of https://github.com/pytorch/pytorch/pull/133113

I have to create a new PR because the previous reverted PR could not either be rebased, or imported successfully :(

----

Moving DTensor to be in the public namespace, to formally add the documentation page that includes all the public APIs. This includes:

* many path renames and path import fixes
* a dedicated doc page without too much content yet (adding in the next PRs)
* To preserve the BC for users still using the torch.distributed._tensor, I added a shim script to redirect old path calls to the new module

The BC preserving is evidented by the fact that all DTensor tests are still working without changing the public imports. So it's safe to land the changes

Pull Request resolved: https://github.com/pytorch/pytorch/pull/134203
Approved by: https://github.com/tianyu-l
2024-09-08 17:08:40 +00:00

344 lines
13 KiB
Python

# Owner(s): ["oncall: distributed"]
from itertools import chain
import torch
from torch.distributed._tensor import DeviceMesh, DTensor
from torch.distributed._tensor.placement_types import (
DTensorSpec,
Partial,
Replicate,
Shard,
TensorMeta,
)
from torch.distributed.tensor._collective_utils import redistribute_cost
from torch.distributed.tensor._op_schema import OpSchema, OpStrategy, PlacementStrategy
from torch.distributed.tensor._ops._einsum_strategy import (
EinsumDims,
gen_einsum_strategies,
)
from torch.testing._internal.common_utils import run_tests, TestCase
from torch.testing._internal.distributed._tensor.common_dtensor import DTensorOpTestBase
class TestEinsumDims(TestCase):
def test_batch_dims(self):
equation = "abc,abc->abc"
input_dims, output_dim = EinsumDims.parse_equation(equation)
edims = EinsumDims.parse_dims(input_dims, output_dim)
self.assertEqual(edims.batch_dims, ["a", "b", "c"])
self.assertEqual(edims.contracting_dims, [])
self.assertEqual(edims.lhs_out_only_dims, [])
self.assertEqual(edims.rhs_out_only_dims, [])
def test_mm_dims(self):
equation = "mk,kn->mn"
input_dims, output_dim = EinsumDims.parse_equation(equation)
edims = EinsumDims.parse_dims(input_dims, output_dim)
self.assertEqual(edims.batch_dims, [])
self.assertEqual(edims.contracting_dims, ["k"])
self.assertEqual(edims.lhs_out_only_dims, ["m"])
self.assertEqual(edims.rhs_out_only_dims, ["n"])
def test_bmm_dims(self):
equation = "bmk,bkn->bmn"
input_dims, output_dim = EinsumDims.parse_equation(equation)
edims = EinsumDims.parse_dims(input_dims, output_dim)
self.assertEqual(edims.batch_dims, ["b"])
self.assertEqual(edims.contracting_dims, ["k"])
self.assertEqual(edims.lhs_out_only_dims, ["m"])
self.assertEqual(edims.rhs_out_only_dims, ["n"])
equation = "bcmk,bckn->bcmn"
input_dims, output_dim = EinsumDims.parse_equation(equation)
edims = EinsumDims.parse_dims(input_dims, output_dim)
self.assertEqual(edims.batch_dims, ["b", "c"])
self.assertEqual(edims.contracting_dims, ["k"])
self.assertEqual(edims.lhs_out_only_dims, ["m"])
self.assertEqual(edims.rhs_out_only_dims, ["n"])
def test_free_dims(self):
equation = "abc,ab->abc"
input_dims, output_dim = EinsumDims.parse_equation(equation)
edims = EinsumDims.parse_dims(input_dims, output_dim)
self.assertEqual(edims.batch_dims, ["a", "b"])
self.assertEqual(edims.contracting_dims, [])
self.assertEqual(edims.lhs_out_only_dims, ["c"])
self.assertEqual(edims.rhs_out_only_dims, [])
equation = "abd,bf->abfd"
input_dims, output_dim = EinsumDims.parse_equation(equation)
edims = EinsumDims.parse_dims(input_dims, output_dim)
self.assertEqual(edims.batch_dims, ["b"])
self.assertEqual(edims.contracting_dims, [])
self.assertEqual(edims.lhs_out_only_dims, ["a", "d"])
self.assertEqual(edims.rhs_out_only_dims, ["f"])
class TestEinsumStrategies(DTensorOpTestBase):
@property
def world_size(self) -> int:
return 4
def test_mm_1d_mesh(self):
mesh = self.build_device_mesh()
all_strats = gen_einsum_strategies("mk,kn->mn", mesh)
self.assertEqual(len(all_strats.strategies), 4)
def test_mm_2d_mesh(self):
mesh = DeviceMesh(self.device_type, torch.arange(self.world_size).reshape(2, 2))
all_strats = gen_einsum_strategies("mk,kn->mn", mesh)
self.assertEqual(len(all_strats.strategies), 16)
def test_bmm_1d_mesh(self):
mesh = self.build_device_mesh()
all_strats = gen_einsum_strategies("bmk,bkn->bmn", mesh)
self.assertEqual(len(all_strats.strategies), 5)
def test_bmm_2d_mesh(self):
mesh = DeviceMesh(self.device_type, torch.arange(self.world_size).reshape(2, 2))
all_strats = gen_einsum_strategies("bmk,bkn->bmn", mesh)
self.assertEqual(len(all_strats.strategies), 25)
def test_pointwise_1d_mesh(self):
mesh = self.build_device_mesh()
simple_strats = gen_einsum_strategies("abcd,abcd->abcd", mesh)
self.assertEqual(len(simple_strats.strategies), 5)
broadcast_strats = gen_einsum_strategies("bcd,abcd->abcd", mesh)
self.assertEqual(len(broadcast_strats.strategies), 5)
def test_linearity_1d_mesh(self):
mesh = self.build_device_mesh()
all_strats = gen_einsum_strategies("abcd,abcd->abcd", mesh, linearity=True)
self.assertEqual(len(all_strats.strategies), 6)
class TestCostModel(DTensorOpTestBase):
def _extract_tensor_meta(self, t) -> TensorMeta:
return TensorMeta(t.shape, t.stride(), t.dtype)
@property
def world_size(self) -> int:
return 4
def test_redistribute_cost_mesh_1d(self):
mesh_1d = self.build_device_mesh()
shard_placement = (Shard(0),)
replica_placement = (Replicate(),)
partial_placement = (Partial(),)
global_tensor = torch.randn(10, 10)
global_tensor_meta = self._extract_tensor_meta(global_tensor)
# shard spec
shard_spec = DTensorSpec(mesh_1d, shard_placement, global_tensor_meta)
# replica spec
replica_spec = DTensorSpec(mesh_1d, replica_placement, global_tensor_meta)
# partial spec
partial_spec = DTensorSpec(mesh_1d, partial_placement, global_tensor_meta)
# make sure reshard cost is 0 for the same spec redistribute
for spec in [shard_spec, replica_spec, partial_spec]:
cost = redistribute_cost(spec, spec)
self.assertEqual(cost, 0)
# shard -> replicate
allgather_cost = redistribute_cost(shard_spec, replica_spec)
# partial -> shard
reduce_scatter_cost = redistribute_cost(partial_spec, shard_spec)
# partial -> replicate
allreduce_cost = redistribute_cost(partial_spec, replica_spec)
self.assertEqual(allgather_cost, reduce_scatter_cost)
self.assertTrue(allreduce_cost + 1 < allgather_cost + reduce_scatter_cost)
# shard to partial
cost = redistribute_cost(shard_spec, partial_spec)
self.assertEqual(cost, float("inf"))
def test_redistribute_cost_latency(self):
# test cost model on addmm op
from torch.distributed.tensor._ops._matrix_ops import addmm_strategy
mesh = self.build_device_mesh()
shard0_placement = (Shard(0),)
partial_placement = (Partial(),)
shard1_placement = (Shard(1),)
shard0_tensor_meta = self._extract_tensor_meta(torch.randn(8))
partial_tensor_meta = self._extract_tensor_meta(torch.randn(50, 6))
shard1_tensor_meta = self._extract_tensor_meta(torch.randn(6, 8))
# shard spec
shard0_spec = DTensorSpec(mesh, shard0_placement, shard0_tensor_meta)
# replica spec
partial_spec = DTensorSpec(mesh, partial_placement, partial_tensor_meta)
# partial spec
shard1_spec = DTensorSpec(mesh, shard1_placement, shard1_tensor_meta)
op_schema = OpSchema(
torch.ops.aten.addmm.default,
(
OpStrategy([PlacementStrategy(shard0_spec)]),
OpStrategy([PlacementStrategy(partial_spec)]),
OpStrategy([PlacementStrategy(shard1_spec)]),
),
{},
)
output_strategy = addmm_strategy(mesh, op_schema)
strategy_costs = {}
for strategy in output_strategy.strategies:
redistribute_cost = sum(chain.from_iterable(strategy.redistribute_cost))
strategy_costs[str(strategy)] = redistribute_cost
# assert that cost model counts for collective latency (i.e. multiple comm is penalized)
self.assertTrue(
strategy_costs["(S(0), R, S(1)) -> S(1)"]
< strategy_costs["(R, S(0), R) -> S(0)"]
)
# assert a single allreduce is the best one
self.assertEqual(
strategy_costs["(S(0), R, S(1)) -> S(1)"], min(strategy_costs.values())
)
def test_redistribute_cost_mesh_2d(self):
mesh_2d = DeviceMesh(
self.device_type, torch.arange(self.world_size).reshape(2, 2)
)
shard_placement = (Shard(0), Shard(0))
replica_placement = (Replicate(), Replicate())
partial_placement = (Partial(), Partial())
global_tensor = torch.randn(8, 8)
global_tensor_meta = self._extract_tensor_meta(global_tensor)
# shard spec
shard_spec = DTensorSpec(mesh_2d, shard_placement, global_tensor_meta)
# replica spec
replica_spec = DTensorSpec(mesh_2d, replica_placement, global_tensor_meta)
# partial spec
partial_spec = DTensorSpec(mesh_2d, partial_placement, global_tensor_meta)
# make sure reshard cost is 0 for the same spec redistribute
for spec in [shard_spec, replica_spec, partial_spec]:
cost = redistribute_cost(spec, spec)
self.assertEqual(cost, 0)
# shard -> replicate
allgather_cost = redistribute_cost(shard_spec, replica_spec)
# partial -> replicate
allreduce_cost = redistribute_cost(partial_spec, replica_spec)
# partial -> shard
reduce_scatter_cost = redistribute_cost(partial_spec, shard_spec)
self.assertTrue(allreduce_cost > allgather_cost)
self.assertTrue(allreduce_cost > reduce_scatter_cost)
def test_mm_strategies(self):
from torch.distributed.tensor._ops._matrix_ops import mm_strategy
mesh = self.build_device_mesh()
lhs_tensor = torch.randn(6, 8)
rhs_tensor = torch.randn(8, 12)
lhs_tensor_meta = self._extract_tensor_meta(lhs_tensor)
rhs_tensor_meta = self._extract_tensor_meta(rhs_tensor)
mm_combs = (
(Shard(0), Replicate()),
(Replicate(), Shard(1)),
(Shard(1), Shard(0)),
(Replicate(), Replicate()),
)
for lhs, rhs in mm_combs:
lhs_spec = DTensorSpec(mesh, (lhs,), lhs_tensor_meta)
rhs_spec = DTensorSpec(mesh, (rhs,), rhs_tensor_meta)
op_schema = OpSchema(
torch.ops.aten.mm.default,
(
OpStrategy([PlacementStrategy(lhs_spec)]),
OpStrategy([PlacementStrategy(rhs_spec)]),
),
{},
)
# test the strategy
res_strategies = mm_strategy(mesh, op_schema)
for strtgy in res_strategies.strategies:
if strtgy.input_specs == (lhs_spec, rhs_spec):
self.assertEqual(strtgy.redistribute_cost, [[0.0], [0.0]])
break
op_schema = OpSchema(
torch.ops.aten.mm.default,
(lhs_spec, rhs_spec),
{},
)
# test sharding prop
output_sharding = DTensor._op_dispatcher.sharding_propagator.propagate_op_sharding_non_cached(
op_schema
)
self.assertFalse(output_sharding.needs_redistribute)
def test_bmm_strategies(self):
from torch.distributed.tensor._ops._matrix_ops import bmm_strategy
mesh = self.build_device_mesh()
lhs_tensor = torch.randn(8, 6, 8)
rhs_tensor = torch.randn(8, 8, 12)
lhs_tensor_meta = self._extract_tensor_meta(lhs_tensor)
rhs_tensor_meta = self._extract_tensor_meta(rhs_tensor)
bmm_combs = (
(Shard(0), Shard(0)),
(Shard(1), Replicate()),
(Replicate(), Shard(2)),
(Shard(2), Shard(1)),
(Replicate(), Replicate()),
)
for lhs, rhs in bmm_combs:
lhs_spec = DTensorSpec(mesh, (lhs,), lhs_tensor_meta)
rhs_spec = DTensorSpec(mesh, (rhs,), rhs_tensor_meta)
op_schema = OpSchema(
torch.ops.aten.bmm.default,
(
OpStrategy([PlacementStrategy(lhs_spec)]),
OpStrategy([PlacementStrategy(rhs_spec)]),
),
{},
)
# test the strategy
res_strategies = bmm_strategy(mesh, op_schema)
for strtgy in res_strategies.strategies:
if strtgy.input_specs == (lhs_spec, rhs_spec):
self.assertEqual(strtgy.redistribute_cost, [[0.0], [0.0]])
break
op_schema = OpSchema(
torch.ops.aten.bmm.default,
(lhs_spec, rhs_spec),
{},
)
# test sharding prop
output_sharding = DTensor._op_dispatcher.sharding_propagator.propagate_op_sharding_non_cached(
op_schema
)
self.assertFalse(output_sharding.needs_redistribute)
if __name__ == "__main__":
run_tests()