pytorch/test/distributed/checkpoint/test_planner.py
Eddy Ogola Onyango cbcd9083be [DCP] Modify tensor saving logic in DCP (#106415)
Currently, DCP treats tensors as duplicates and only saves them on rank0. This won't work for PiPPy as PiPPy does have unique tensors across different ranks. With the current setup, we would only be saving the tensors on rank0 (coordinator rank).

In this PR, we are changing to letting each rank create its own WriteItem for tensors. For the ones that does replicate across different ranks, we are handling it thru dedup_tensors(), which will dedup the replicate WriteItem so we only do the actual writing once.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106415
Approved by: https://github.com/wz337
2023-08-09 00:16:10 +00:00

330 lines
14 KiB
Python

# Owner(s): ["oncall: distributed"]
import sys
import torch
from torch.distributed.checkpoint.planner import LoadItemType, WriteItemType
from torch.distributed._shard.sharded_tensor import (
Shard,
ShardMetadata,
ShardedTensor,
ShardedTensorMetadata,
)
from torch.distributed._shard.sharded_tensor.metadata import TensorProperties
from torch.testing._internal.common_utils import (
TestCase,
TEST_WITH_DEV_DBG_ASAN,
run_tests,
)
from torch.distributed.checkpoint.metadata import (
BytesStorageMetadata,
MetadataIndex,
TensorStorageMetadata,
ChunkStorageMetadata,
)
from torch.testing._internal.distributed.distributed_utils import (
with_fake_comms,
with_dist
)
from torch.distributed.checkpoint.default_planner import (
create_default_global_save_plan,
create_default_local_save_plan,
create_default_local_load_plan,
_create_default_local_metadata
)
from torch.distributed.checkpoint.planner_helpers import create_read_items_for_chunk_list
from torch.distributed.checkpoint._dedup_tensors import dedup_tensors
if TEST_WITH_DEV_DBG_ASAN:
print(
"Skip dev-asan as torch + multiprocessing spawn have known issues",
file=sys.stderr,
)
sys.exit(0)
def create_sharded_tensor(rank, world_size, shards_per_rank, shard_size=8):
shards_metadata = []
local_shards = []
for idx in range(0, world_size * shards_per_rank):
shard_rank = idx // shards_per_rank
shard_md = ShardMetadata(shard_offsets=[idx * shard_size], shard_sizes=[shard_size], placement=f"rank:{shard_rank}/cpu")
shards_metadata.append(shard_md)
if shard_rank == rank:
shard = Shard.from_tensor_and_offsets(
torch.rand(*shard_md.shard_sizes),
shard_offsets=shard_md.shard_offsets,
rank=rank
)
local_shards.append(shard)
sharded_tensor_md = ShardedTensorMetadata(
shards_metadata=shards_metadata,
size=torch.Size([shard_size * len(shards_metadata)]),
tensor_properties=TensorProperties.create_from_tensor(torch.zeros(1))
)
return ShardedTensor._init_from_local_shards_and_global_metadata(
local_shards=local_shards,
sharded_tensor_metadata=sharded_tensor_md
)
class TestSavePlan(TestCase):
@with_fake_comms(rank=1, world_size=4)
def test_local_plan(self):
tensor = torch.rand(10)
val = [1, 2, 3]
st = create_sharded_tensor(rank=1, world_size=4, shards_per_rank=1)
state_dict = {
"tensor": tensor,
"value": val,
"st": st
}
plan = create_default_local_save_plan(state_dict, False)
self.assertEqual(2, len(plan.items))
wi = plan.items[0]
self.assertEqual(wi.index, MetadataIndex("tensor", [0]))
self.assertEqual(wi.type, WriteItemType.TENSOR)
self.assertEqual(wi.tensor_data.size, tensor.size())
self.assertEqual(wi.tensor_data.properties, TensorProperties.create_from_tensor(torch.zeros(1)))
self.assertEqual(wi.tensor_data.chunk.offsets, torch.Size([0]))
self.assertEqual(wi.tensor_data.chunk.sizes, torch.Size([10]))
st_wi = plan.items[1]
self.assertEqual(st_wi.index, MetadataIndex("st", [8]))
self.assertEqual(st_wi.type, WriteItemType.SHARD)
self.assertEqual(st_wi.tensor_data.size, st.size())
self.assertEqual(st_wi.tensor_data.properties, TensorProperties.create_from_tensor(torch.zeros(1)))
self.assertEqual(st_wi.tensor_data.chunk.offsets, torch.Size([8]))
self.assertEqual(st_wi.tensor_data.chunk.sizes, torch.Size([8]))
# Coordinator rank, should include replicated items as well
plan = create_default_local_save_plan(state_dict, True)
self.assertEqual(3, len(plan.items))
tensor_wi = next(wi for wi in plan.items if wi.type == WriteItemType.TENSOR)
self.assertEqual(tensor_wi.index, MetadataIndex("tensor", [0]))
self.assertEqual(tensor_wi.tensor_data.size, tensor.size())
self.assertEqual(tensor_wi.tensor_data.properties, TensorProperties.create_from_tensor(tensor))
self.assertEqual(tensor_wi.tensor_data.chunk.offsets, torch.Size([0]))
self.assertEqual(tensor_wi.tensor_data.chunk.sizes, torch.Size([10]))
bytes_wi = next(wi for wi in plan.items if wi.type == WriteItemType.BYTE_IO)
self.assertEqual(bytes_wi.index, MetadataIndex("value"))
self.assertIsNone(bytes_wi.tensor_data)
def test_global_plan(self):
def create_data(rank):
with with_dist(rank=rank, world_size=4):
tensor = torch.rand(10)
val = [1, 2, 3]
st = create_sharded_tensor(rank=rank, world_size=4, shards_per_rank=1)
state_dict = {
"tensor": tensor,
"value": val,
"st": st
}
return create_default_local_save_plan(state_dict, rank == 0)
all_plans = [create_data(0), create_data(1), create_data(2), create_data(3)]
all_plans = dedup_tensors(all_plans)
final_plans, metadata = create_default_global_save_plan(all_plans=all_plans)
# The default global plan updates all indexes to include hints
for new_plan, old_plan in zip(final_plans, all_plans):
for new_item, old_item in zip(new_plan.items, old_plan.items):
self.assertEqual(new_item.index, old_item.index)
self.assertEqual(new_item.type, old_item.type)
self.assertEqual(new_item.tensor_data, old_item.tensor_data)
self.assertIn(new_item.index.fqn, metadata.state_dict_metadata)
item_md = metadata.state_dict_metadata[new_item.index.fqn]
if new_item.type == WriteItemType.BYTE_IO:
self.assertTrue(isinstance(item_md, BytesStorageMetadata))
else:
self.assertTrue(isinstance(item_md, TensorStorageMetadata))
self.assertEqual(item_md.size, old_item.tensor_data.size)
self.assertEqual(item_md.properties, old_item.tensor_data.properties)
self.assertIsNotNone(new_item.index.index)
# Make sure the hint is correct
self.assertEqual(item_md.chunks[new_item.index.index], old_item.tensor_data.chunk)
def test_local_load_plan(self):
def create_state_dict(rank):
with with_dist(rank=rank, world_size=4):
tensor = torch.rand(10)
val = [1, 2, 3]
st = create_sharded_tensor(rank=rank, world_size=4, shards_per_rank=1)
return {
"tensor": tensor,
"value": val,
"st": st
}
state_dict = create_state_dict(1)
metadata = _create_default_local_metadata(state_dict)
load_plan = create_default_local_load_plan(state_dict, metadata)
# This will create 3 entries
self.assertEqual(3, len(load_plan.items))
st_item = next(ri for ri in load_plan.items if ri.dest_index.fqn == "st")
tensor_item = next(ri for ri in load_plan.items if ri.dest_index.fqn == "tensor")
bytes_item = next(ri for ri in load_plan.items if ri.dest_index.fqn == "value")
self.assertEqual(st_item.type, LoadItemType.TENSOR)
# This is an exact copy
self.assertEqual(st_item.dest_index, MetadataIndex("st", [8]))
self.assertEqual(st_item.dest_offsets, torch.Size([0]))
self.assertEqual(st_item.storage_index, MetadataIndex("st", [8]))
self.assertEqual(st_item.storage_offsets, torch.Size([0]))
self.assertEqual(st_item.lengths, torch.Size([8]))
self.assertEqual(tensor_item.type, LoadItemType.TENSOR)
self.assertEqual(tensor_item.dest_index, MetadataIndex("tensor", [0]))
self.assertEqual(tensor_item.dest_offsets, torch.Size([0]))
self.assertEqual(tensor_item.storage_index, MetadataIndex("tensor", [0]))
self.assertEqual(tensor_item.storage_offsets, torch.Size([0]))
self.assertEqual(tensor_item.lengths, torch.Size([10]))
self.assertEqual(bytes_item.type, LoadItemType.BYTE_IO)
self.assertEqual(bytes_item.dest_index, MetadataIndex("value"))
def test_load_with_resharding(self):
def create_state_dict(rank, world_size):
with with_dist(rank=rank, world_size=world_size):
return {
"st": create_sharded_tensor(
rank=rank,
world_size=world_size,
shards_per_rank=1,
shard_size=128 // world_size,
)
}
# Rank 1 has a 16 bytes shard from [16, 32[
world8_state_dict = create_state_dict(rank=1, world_size=8)
world8_metadata = _create_default_local_metadata(world8_state_dict)
# Rank 1 has a 32 bytes shard from [32, 64[
world4_state_dict = create_state_dict(rank=1, world_size=4)
world4_metadata = _create_default_local_metadata(world4_state_dict)
# First scenario, going from world=8 to world=4, need to load 2 shards
# Each 4-world shard has 32 elements, so it needs to load 2 shards
load_plan = create_default_local_load_plan(world4_state_dict, world8_metadata)
self.assertEqual(2, len(load_plan.items))
low_ri = next(ri for ri in load_plan.items if ri.dest_offsets == torch.Size([0]))
high_ri = next(ri for ri in load_plan.items if ri.dest_offsets == torch.Size([16]))
self.assertEqual(low_ri.storage_index, MetadataIndex("st", [32]))
self.assertEqual(low_ri.storage_offsets, torch.Size([0]))
self.assertEqual(low_ri.dest_index, MetadataIndex("st", [32]))
self.assertEqual(low_ri.dest_offsets, torch.Size([0]))
self.assertEqual(low_ri.lengths, torch.Size([16]))
self.assertEqual(high_ri.storage_index, MetadataIndex("st", [48]))
self.assertEqual(high_ri.storage_offsets, torch.Size([0]))
self.assertEqual(high_ri.dest_index, MetadataIndex("st", [32]))
self.assertEqual(high_ri.dest_offsets, torch.Size([16]))
self.assertEqual(high_ri.lengths, torch.Size([16]))
# Second scenario, going from world=4 to world=8, need to load half of 1 shard
# rank1 on 8-world needs to load the upper half of the rank0 4-world shard
load_plan = create_default_local_load_plan(world8_state_dict, world4_metadata)
self.assertEqual(1, len(load_plan.items))
ri = load_plan.items[0]
self.assertEqual(ri.storage_index, MetadataIndex("st", [0]))
self.assertEqual(ri.storage_offsets, torch.Size([16]))
self.assertEqual(ri.dest_index, MetadataIndex("st", [16]))
self.assertEqual(ri.dest_offsets, torch.Size([0]))
self.assertEqual(ri.lengths, torch.Size([16]))
def test_load_with_world_size_diff_by_one(self):
def create_state_dict(rank, world_size):
with with_dist(rank=rank, world_size=world_size):
return {
"st": create_sharded_tensor(
rank=rank,
world_size=world_size,
shards_per_rank=1,
shard_size=120 // world_size,
)
}
# rank 1 has a 30 bytes shard from [30, 60[
world4_state_dict = create_state_dict(rank=1, world_size=4)
world4_metadata = _create_default_local_metadata(world4_state_dict)
# rank 1 has a 40 bytes shard from [40, 80[
world3_state_dict = create_state_dict(rank=1, world_size=3)
load_plan = create_default_local_load_plan(world3_state_dict, world4_metadata)
self.assertEqual(2, len(load_plan.items))
# this is [30, 60] to load [40, 60]
low_ri = next(ri for ri in load_plan.items if ri.dest_offsets == torch.Size([0]))
# this is [60, 90] to load [60, 80]
high_ri = next(ri for ri in load_plan.items if ri.dest_offsets == torch.Size([20]))
self.assertEqual(low_ri.storage_index, MetadataIndex("st", [30]))
self.assertEqual(low_ri.storage_offsets, torch.Size([10]))
self.assertEqual(low_ri.dest_index, MetadataIndex("st", [40]))
self.assertEqual(low_ri.dest_offsets, torch.Size([0]))
self.assertEqual(low_ri.lengths, torch.Size([20]))
self.assertEqual(high_ri.storage_index, MetadataIndex("st", [60]))
self.assertEqual(high_ri.storage_offsets, torch.Size([0]))
self.assertEqual(high_ri.dest_index, MetadataIndex("st", [40]))
self.assertEqual(high_ri.dest_offsets, torch.Size([20]))
self.assertEqual(high_ri.lengths, torch.Size([20]))
class TestPlannerHelpers(TestCase):
def test_create_read_item_from_chunks(self):
tensor_md = TensorStorageMetadata(
properties=TensorProperties.create_from_tensor(torch.empty([16])),
size=torch.Size([16]),
chunks=[
ChunkStorageMetadata(
offsets=torch.Size([0]),
sizes=torch.Size([8])
),
ChunkStorageMetadata(
offsets=torch.Size([8]),
sizes=torch.Size([8])
)
]
)
chunk = ChunkStorageMetadata(
offsets=torch.Size([4]),
sizes=torch.Size([7])
)
read_items = create_read_items_for_chunk_list("foo", tensor_md, [chunk])
self.assertEqual(2, len(read_items))
self.assertEqual(MetadataIndex("foo", [4]), read_items[0].dest_index)
self.assertEqual(torch.Size([0]), read_items[0].dest_offsets)
self.assertEqual(MetadataIndex("foo", [0]), read_items[0].storage_index)
self.assertEqual(torch.Size([4]), read_items[0].storage_offsets)
self.assertEqual(torch.Size([4]), read_items[0].lengths)
self.assertEqual(MetadataIndex("foo", [4]), read_items[1].dest_index)
self.assertEqual(torch.Size([4]), read_items[1].dest_offsets)
self.assertEqual(MetadataIndex("foo", [8]), read_items[1].storage_index)
self.assertEqual(torch.Size([0]), read_items[1].storage_offsets)
self.assertEqual(torch.Size([3]), read_items[1].lengths)
if __name__ == "__main__":
run_tests()