Support multi axis unsharding in dump comparator (#19280)

This commit is contained in:
fzyzcjy
2026-02-25 09:44:07 +08:00
committed by GitHub
parent 4bb678f28a
commit 0de1f4b07b
7 changed files with 706 additions and 96 deletions

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@@ -82,9 +82,8 @@ def _compute_plans_for_group(metas: list[dict[str, Any]]) -> list[Plan]:
dim_specs = parse_dims(dims_str)
parallel_infos = [normalize_parallel_info(meta) for meta in metas]
plan = compute_unshard_plan(dim_specs=dim_specs, parallel_infos=parallel_infos)
return [plan] if plan is not None else []
return compute_unshard_plan(dim_specs=dim_specs, parallel_infos=parallel_infos)
def _extract_tensors(
@@ -105,15 +104,12 @@ def _execute_plans(
return None
return tensors[0]
assert len(plans) <= 1, "multi-plan not supported yet"
current = tensors
for plan in plans:
if isinstance(plan, UnshardPlan):
# TODO: incorrect `tensors_by_world_rank` if multi UnshardPlan
tensors = execute_unshard_plan(
plan, tensors_by_world_rank=dict(enumerate(tensors))
)
current = execute_unshard_plan(plan, current)
else:
raise NotImplementedError(f"Unknown {plan=}")
return tensors
assert len(current) == 1
return current[0]

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@@ -2,26 +2,25 @@ import torch
from sglang.srt.debug_utils.comparator.unshard.types import (
ConcatParams,
UnshardParams,
UnshardPlan,
)
def execute_unshard_plan(
plan: UnshardPlan,
tensors_by_world_rank: dict[int, torch.Tensor],
) -> torch.Tensor:
ordered_tensors = [
tensors_by_world_rank[world_rank]
for world_rank in plan.world_ranks_by_axis_rank
]
return _apply_unshard(plan, ordered_tensors)
tensors: list[torch.Tensor],
) -> list[torch.Tensor]:
result: list[torch.Tensor] = []
for group in plan.groups:
group_tensors = [tensors[i] for i in group]
result.append(_apply_unshard(plan.params, group_tensors))
return result
def _apply_unshard(
plan: UnshardPlan, ordered_tensors: list[torch.Tensor]
params: UnshardParams, ordered_tensors: list[torch.Tensor]
) -> torch.Tensor:
params = plan.params
if isinstance(params, ConcatParams):
return _unshard_concat(ordered_tensors, dim=params.dim)
# Phase 2: ReduceSumParams, CpZigzagParams

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@@ -1,4 +1,5 @@
from typing import Optional
from collections import defaultdict
from typing import NamedTuple
from sglang.srt.debug_utils.comparator.dims import DimSpec, Ordering, ParallelAxis
from sglang.srt.debug_utils.comparator.unshard.types import (
@@ -8,64 +9,117 @@ from sglang.srt.debug_utils.comparator.unshard.types import (
UnshardPlan,
)
# _CoordsList[tensor_index][axis] =
# the axis_rank (shard position) of the tensor_index-th tensor along `axis`
# (e.g. coords[2] = {TP: 3} means tensor 2 is the 3rd shard in TP axis)
_CoordsList = list[dict[ParallelAxis, int]]
class _GroupResult(NamedTuple):
groups: list[list[int]]
projected_coords: _CoordsList
def compute_unshard_plan(
dim_specs: list[DimSpec],
parallel_infos: list[dict[ParallelAxis, AxisInfo]],
) -> Optional[UnshardPlan]:
) -> list[UnshardPlan]:
if not parallel_infos:
raise ValueError("parallel_infos must not be empty")
sharded_axes: dict[ParallelAxis, tuple[int, DimSpec]] = {}
for dim_idx, spec in enumerate(dim_specs):
if spec.parallel is not None:
sharded_axes[spec.parallel] = (dim_idx, spec)
sharded_axis_infos: dict[ParallelAxis, tuple[int, DimSpec]] = {
spec.parallel: (dim_idx, spec)
for dim_idx, spec in enumerate(dim_specs)
if spec.parallel is not None
}
if not sharded_axis_infos:
return []
if len(sharded_axes) > 1:
raise NotImplementedError(
f"Multi-axis unshard is not supported. "
f"Got {len(sharded_axes)} sharded axes: {sorted(a.value for a in sharded_axes)}"
_validate(sharded_axes=set(sharded_axis_infos), parallel_infos=parallel_infos)
current_coords: _CoordsList = [
{axis: info[axis].axis_rank for axis in sharded_axis_infos}
for info in parallel_infos
]
plans: list[UnshardPlan] = []
for axis, (dim_index, spec) in sharded_axis_infos.items():
result = _group_and_project(
current_coords=current_coords,
target_axis=axis,
)
if not sharded_axes:
return None
plans.append(
UnshardPlan(
axis=axis,
params=_resolve_unshard_params(spec=spec, dim_index=dim_index),
groups=result.groups,
)
)
axis_name, (dim_idx, spec) = next(iter(sharded_axes.items()))
current_coords = result.projected_coords
expected_size: Optional[int] = None
rank_to_world: dict[int, int] = {}
return plans
for world_rank, pinfo in enumerate(parallel_infos):
if axis_name not in pinfo:
continue
ainfo = pinfo[axis_name]
def _validate(
*,
sharded_axes: set[ParallelAxis],
parallel_infos: list[dict[ParallelAxis, AxisInfo]],
) -> None:
"""Check that every rank has all sharded axes, sizes are consistent, and ranks are complete."""
axis_sizes: dict[ParallelAxis, int] = {}
if expected_size is None:
expected_size = ainfo.axis_size
elif ainfo.axis_size != expected_size:
for world_rank, parallel_info in enumerate(parallel_infos):
for axis in sharded_axes:
if axis not in parallel_info:
raise ValueError(
f"world_rank={world_rank} missing parallel_info for "
f"sharded axis {axis.value!r}"
)
axis_info = parallel_info[axis]
if axis not in axis_sizes:
axis_sizes[axis] = axis_info.axis_size
elif axis_info.axis_size != axis_sizes[axis]:
raise ValueError(
f"Inconsistent axis_size for {axis.value}: "
f"expected {axis_sizes[axis]}, got {axis_info.axis_size} "
f"at world_rank={world_rank}"
)
for axis, expected_size in axis_sizes.items():
seen_ranks = {info[axis].axis_rank for info in parallel_infos}
if seen_ranks != set(range(expected_size)):
raise ValueError(
f"Inconsistent axis_size for {axis_name.value}: "
f"expected {expected_size}, got {ainfo.axis_size} "
f"at world_rank={world_rank}"
f"axis_rank coverage for {axis.value} is incomplete: "
f"got {sorted(seen_ranks)}, expected 0..{expected_size - 1}"
)
rank_to_world.setdefault(ainfo.axis_rank, world_rank)
if expected_size is None:
raise ValueError(f"No parallel_info found for sharded axis {axis_name.value!r}")
def _group_and_project(
*,
current_coords: _CoordsList,
target_axis: ParallelAxis,
) -> _GroupResult:
"""Group tensors by other-axes coords, sort within group by target_axis rank."""
# buckets[coords_excluding_target] = [(axis_rank, tensor_index), ...]
# e.g. when target_axis=CP: buckets[{(TP,0)}] = [(0, 1), (1, 3)]
# means tensor 1 (CP rank 0) and tensor 3 (CP rank 1) share TP rank 0
buckets: dict[frozenset, list[tuple[int, int]]] = defaultdict(list)
if set(rank_to_world.keys()) != set(range(expected_size)):
raise ValueError(
f"axis_rank coverage for {axis_name.value} is incomplete: "
f"got {sorted(rank_to_world.keys())}, expected 0..{expected_size - 1}"
)
for idx, coords in enumerate(current_coords):
key = frozenset((k, v) for k, v in coords.items() if k != target_axis)
buckets[key].append((coords[target_axis], idx))
return UnshardPlan(
axis=spec.parallel,
params=_resolve_unshard_params(spec=spec, dim_index=dim_idx),
world_ranks_by_axis_rank=[rank_to_world[i] for i in range(expected_size)],
)
groups: list[list[int]] = []
projected: _CoordsList = []
for key in sorted(buckets, key=lambda k: sorted((a.value, v) for a, v in k)):
entries = sorted(buckets[key])
groups.append([idx for _, idx in entries])
projected.append(dict(key))
return _GroupResult(groups=groups, projected_coords=projected)
def _resolve_unshard_params(*, spec: DimSpec, dim_index: int) -> UnshardParams:

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@@ -27,7 +27,12 @@ UnshardParams = ConcatParams
class UnshardPlan(_FrozenBase):
axis: ParallelAxis
params: UnshardParams
world_ranks_by_axis_rank: list[int]
# groups[i] = indices in the input tensor list, which will be operated (e.g. concat) into i-th output tensor.
#
# Multistep example (CP=2, TP=2, 4 input tensors):
# plan[0] (CP): groups=[[0,2],[1,3]] — 4 tensors → 2 tensors
# plan[1] (TP): groups=[[0,1]] — 2 tensors → 1 tensor
groups: list[list[int]]
# Union of all plan types. Future pipeline components (e.g. reduction,

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@@ -701,6 +701,114 @@ class TestEntrypointGroupingLogical:
assert summary.total == 2
assert summary.passed == 2
def test_cp_tp_unshard(self, tmp_path, capsys):
"""CP=2 + TP=2: multi-axis shards are unsharded before comparison."""
torch.manual_seed(42)
full_baseline = torch.randn(4, 8, 16)
full_target = full_baseline + torch.randn(4, 8, 16) * 0.001
baseline_dir = tmp_path / "baseline"
target_dir = tmp_path / "target"
for side_dir, full_tensor in [
(baseline_dir, full_baseline),
(target_dir, full_target),
]:
_create_cp_tp_sharded_dumps(
side_dir,
full_tensor=full_tensor,
name="hidden",
cp_size=2,
tp_size=2,
seq_dim=1,
head_dim=2,
dims_str="b s(cp) h(tp)",
)
args = _make_args(
baseline_dir / _FIXED_EXP_NAME,
target_dir / _FIXED_EXP_NAME,
diff_threshold=0.01,
)
records = _run_and_parse(args, capsys)
comp = _assert_single_comparison_passed(records)
assert comp.name == "hidden"
def test_cp_tp_different_sizes(self, tmp_path, capsys):
"""Baseline CP=2+TP=2 vs target CP=1+TP=4: both sides independently unshard."""
torch.manual_seed(42)
full_baseline = torch.randn(4, 8, 16)
full_target = full_baseline + torch.randn(4, 8, 16) * 0.001
baseline_dir = tmp_path / "baseline"
target_dir = tmp_path / "target"
_create_cp_tp_sharded_dumps(
baseline_dir,
full_tensor=full_baseline,
name="hidden",
cp_size=2,
tp_size=2,
seq_dim=1,
head_dim=2,
dims_str="b s(cp) h(tp)",
)
_create_tp_sharded_dumps(
target_dir,
full_tensor=full_target,
name="hidden",
tp_size=4,
shard_dim=2,
dims_str="b s h(tp)",
)
args = _make_args(
baseline_dir / _FIXED_EXP_NAME,
target_dir / _FIXED_EXP_NAME,
diff_threshold=0.01,
)
records = _run_and_parse(args, capsys)
_assert_single_comparison_passed(records)
def test_ep_cp_tp_three_axis_unshard(self, tmp_path, capsys):
"""EP=2 + CP=2 + TP=2: three-axis shards are unsharded before comparison."""
torch.manual_seed(42)
full_baseline = torch.randn(4, 8, 16, 32)
full_target = full_baseline + torch.randn(4, 8, 16, 32) * 0.001
baseline_dir = tmp_path / "baseline"
target_dir = tmp_path / "target"
for side_dir, full_tensor in [
(baseline_dir, full_baseline),
(target_dir, full_target),
]:
_create_ep_cp_tp_sharded_dumps(
side_dir,
full_tensor=full_tensor,
name="hidden",
ep_size=2,
cp_size=2,
tp_size=2,
expert_dim=1,
seq_dim=2,
head_dim=3,
dims_str="b e(ep) s(cp) h(tp)",
)
args = _make_args(
baseline_dir / _FIXED_EXP_NAME,
target_dir / _FIXED_EXP_NAME,
diff_threshold=0.01,
)
records = _run_and_parse(args, capsys)
comp = _assert_single_comparison_passed(records)
assert comp.name == "hidden"
# --------------------------- Assertion helpers -------------------
@@ -825,6 +933,84 @@ def _create_rank_dump(
return directory / _FIXED_EXP_NAME
def _create_cp_tp_sharded_dumps(
directory: Path,
*,
full_tensor: torch.Tensor,
name: str,
cp_size: int,
tp_size: int,
seq_dim: int,
head_dim: int,
dims_str: str,
num_steps: int = 1,
) -> Path:
"""Create CP+TP multi-axis sharded dump files from a full tensor."""
cp_chunks = list(full_tensor.chunk(cp_size, dim=seq_dim))
rank = 0
for cp_rank in range(cp_size):
tp_chunks = list(cp_chunks[cp_rank].chunk(tp_size, dim=head_dim))
for tp_rank in range(tp_size):
_create_rank_dump(
directory,
rank=rank,
name=name,
tensor=tp_chunks[tp_rank],
dims=dims_str,
parallel_info={
"cp_rank": cp_rank,
"cp_size": cp_size,
"tp_rank": tp_rank,
"tp_size": tp_size,
},
num_steps=num_steps,
)
rank += 1
return directory / _FIXED_EXP_NAME
def _create_ep_cp_tp_sharded_dumps(
directory: Path,
*,
full_tensor: torch.Tensor,
name: str,
ep_size: int,
cp_size: int,
tp_size: int,
expert_dim: int,
seq_dim: int,
head_dim: int,
dims_str: str,
num_steps: int = 1,
) -> Path:
"""Create EP+CP+TP three-axis sharded dump files from a full tensor."""
ep_chunks = list(full_tensor.chunk(ep_size, dim=expert_dim))
rank = 0
for ep_rank in range(ep_size):
cp_chunks = list(ep_chunks[ep_rank].chunk(cp_size, dim=seq_dim))
for cp_rank in range(cp_size):
tp_chunks = list(cp_chunks[cp_rank].chunk(tp_size, dim=head_dim))
for tp_rank in range(tp_size):
_create_rank_dump(
directory,
rank=rank,
name=name,
tensor=tp_chunks[tp_rank],
dims=dims_str,
parallel_info={
"ep_rank": ep_rank,
"ep_size": ep_size,
"cp_rank": cp_rank,
"cp_size": cp_size,
"tp_rank": tp_rank,
"tp_size": tp_size,
},
num_steps=num_steps,
)
rank += 1
return directory / _FIXED_EXP_NAME
def _create_tp_sharded_dumps(
directory: Path,
*,

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@@ -3,8 +3,11 @@ import sys
import pytest
import torch
from sglang.srt.debug_utils.comparator.dims import parse_dims
from sglang.srt.debug_utils.comparator.unshard.executor import execute_unshard_plan
from sglang.srt.debug_utils.comparator.dims import ParallelAxis, parse_dims
from sglang.srt.debug_utils.comparator.unshard.executor import (
_apply_unshard,
execute_unshard_plan,
)
from sglang.srt.debug_utils.comparator.unshard.planner import compute_unshard_plan
from sglang.srt.debug_utils.comparator.unshard.types import AxisInfo
from sglang.test.ci.ci_register import register_cpu_ci
@@ -18,37 +21,240 @@ class TestExecuteUnshardPlan:
shards = list(full_tensor.chunk(4, dim=1))
dim_specs = parse_dims("b h(tp) d")
parallel_infos = [{"tp": AxisInfo(axis_rank=i, axis_size=4)} for i in range(4)]
plan = compute_unshard_plan(dim_specs, parallel_infos)
assert plan is not None
tensors_by_rank = {i: shards[i] for i in range(4)}
parallel_infos = [
{ParallelAxis.TP: AxisInfo(axis_rank=i, axis_size=4)} for i in range(4)
]
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 1
result = execute_unshard_plan(plan, tensors_by_rank)
assert torch.allclose(result, full_tensor)
result = execute_unshard_plan(plans[0], shards)
assert len(result) == 1
assert torch.allclose(result[0], full_tensor)
def test_scrambled_world_ranks_correct_result(self) -> None:
full_tensor = torch.randn(4, 8)
shards = list(full_tensor.chunk(4, dim=0))
parallel_infos = [
{"tp": AxisInfo(axis_rank=2, axis_size=4)},
{"tp": AxisInfo(axis_rank=0, axis_size=4)},
{"tp": AxisInfo(axis_rank=3, axis_size=4)},
{"tp": AxisInfo(axis_rank=1, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=2, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=3, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=4)},
]
dim_specs = parse_dims("h(tp) d")
plan = compute_unshard_plan(dim_specs, parallel_infos)
assert plan is not None
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 1
tensors_by_rank = {
0: shards[2],
1: shards[0],
2: shards[3],
3: shards[1],
}
tensors_ordered_by_world_rank = [
shards[2], # world_rank=0, axis_rank=2
shards[0], # world_rank=1, axis_rank=0
shards[3], # world_rank=2, axis_rank=3
shards[1], # world_rank=3, axis_rank=1
]
result = execute_unshard_plan(plan, tensors_by_rank)
assert torch.allclose(result, full_tensor)
result = execute_unshard_plan(plans[0], tensors_ordered_by_world_rank)
assert len(result) == 1
assert torch.allclose(result[0], full_tensor)
def test_single_step_reduces_tensor_count(self) -> None:
"""8 tensors with 2 groups of 4 produce 2 output tensors."""
full_a = torch.randn(4, 8)
full_b = torch.randn(4, 8)
shards_a = list(full_a.chunk(4, dim=0))
shards_b = list(full_b.chunk(4, dim=0))
dim_specs = parse_dims("s(cp) h(tp)")
parallel_infos = []
for cp_rank in range(2):
for tp_rank in range(4):
parallel_infos.append(
{
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=4),
}
)
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 2
tensors: list[torch.Tensor] = []
for cp_rank in range(2):
source = shards_a if cp_rank == 0 else shards_b
for tp_rank in range(4):
tensors.append(source[tp_rank])
intermediate = execute_unshard_plan(plans[0], tensors)
assert len(intermediate) == 4
final = execute_unshard_plan(plans[1], intermediate)
assert len(final) == 1
def test_cp_tp_concat(self) -> None:
"""CP=2 + TP=2: multi-step unshard reconstructs original tensor."""
torch.manual_seed(42)
full_tensor = torch.randn(4, 8, 16)
cp_chunks = list(full_tensor.chunk(2, dim=1))
tensors: list[torch.Tensor] = []
parallel_infos = []
for cp_rank in range(2):
tp_chunks = list(cp_chunks[cp_rank].chunk(2, dim=2))
for tp_rank in range(2):
tensors.append(tp_chunks[tp_rank])
parallel_infos.append(
{
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=2),
}
)
dim_specs = parse_dims("b s(cp) h(tp)")
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 2
current = tensors
for plan in plans:
current = execute_unshard_plan(plan, current)
assert len(current) == 1
assert torch.allclose(current[0], full_tensor)
def test_cp_tp_scrambled(self) -> None:
"""Scrambled world_ranks for CP=2 + TP=2 still reconstruct correctly."""
torch.manual_seed(42)
full_tensor = torch.randn(4, 8, 16)
cp_chunks = list(full_tensor.chunk(2, dim=1))
shard_map: dict[tuple[int, int], torch.Tensor] = {}
for cp_rank in range(2):
tp_chunks = list(cp_chunks[cp_rank].chunk(2, dim=2))
for tp_rank in range(2):
shard_map[(cp_rank, tp_rank)] = tp_chunks[tp_rank]
scrambled_assignment = [
(1, 1), # world_rank=0
(0, 0), # world_rank=1
(1, 0), # world_rank=2
(0, 1), # world_rank=3
]
tensors: list[torch.Tensor] = []
parallel_infos = []
for cp_rank, tp_rank in scrambled_assignment:
tensors.append(shard_map[(cp_rank, tp_rank)])
parallel_infos.append(
{
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=2),
}
)
dim_specs = parse_dims("b s(cp) h(tp)")
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 2
current = tensors
for plan in plans:
current = execute_unshard_plan(plan, current)
assert len(current) == 1
assert torch.allclose(current[0], full_tensor)
def test_unsupported_params_type_raises(self) -> None:
"""_apply_unshard raises ValueError for unknown params type."""
class _FakeParams:
pass
with pytest.raises(ValueError, match="Unsupported unshard"):
_apply_unshard(_FakeParams(), [torch.randn(2, 2)])
def test_cp_tp_ep_three_axis_concat(self) -> None:
"""CP=2 + TP=2 + EP=2: three-step unshard reconstructs original tensor."""
torch.manual_seed(42)
full_tensor = torch.randn(4, 8, 16, 32)
ep_chunks = list(full_tensor.chunk(2, dim=1))
shard_map: dict[tuple[int, int, int], torch.Tensor] = {}
for ep_rank in range(2):
cp_chunks = list(ep_chunks[ep_rank].chunk(2, dim=2))
for cp_rank in range(2):
tp_chunks = list(cp_chunks[cp_rank].chunk(2, dim=3))
for tp_rank in range(2):
shard_map[(ep_rank, cp_rank, tp_rank)] = tp_chunks[tp_rank]
tensors: list[torch.Tensor] = []
parallel_infos: list[dict[ParallelAxis, AxisInfo]] = []
for ep_rank in range(2):
for cp_rank in range(2):
for tp_rank in range(2):
tensors.append(shard_map[(ep_rank, cp_rank, tp_rank)])
parallel_infos.append(
{
ParallelAxis.EP: AxisInfo(axis_rank=ep_rank, axis_size=2),
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=2),
}
)
dim_specs = parse_dims("b e(ep) s(cp) h(tp)")
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 3
current = tensors
for plan in plans:
current = execute_unshard_plan(plan, current)
assert len(current) == 1
assert torch.allclose(current[0], full_tensor)
def test_cp_tp_ep_scrambled_three_axis(self) -> None:
"""Scrambled ranks for CP=2 + TP=2 + EP=2 still reconstruct correctly."""
torch.manual_seed(42)
full_tensor = torch.randn(4, 8, 16, 32)
ep_chunks = list(full_tensor.chunk(2, dim=1))
shard_map: dict[tuple[int, int, int], torch.Tensor] = {}
for ep_rank in range(2):
cp_chunks = list(ep_chunks[ep_rank].chunk(2, dim=2))
for cp_rank in range(2):
tp_chunks = list(cp_chunks[cp_rank].chunk(2, dim=3))
for tp_rank in range(2):
shard_map[(ep_rank, cp_rank, tp_rank)] = tp_chunks[tp_rank]
scrambled_assignment = [
(1, 0, 1), # world_rank=0
(0, 1, 0), # world_rank=1
(1, 1, 0), # world_rank=2
(0, 0, 0), # world_rank=3
(0, 1, 1), # world_rank=4
(1, 0, 0), # world_rank=5
(0, 0, 1), # world_rank=6
(1, 1, 1), # world_rank=7
]
tensors: list[torch.Tensor] = []
parallel_infos: list[dict[ParallelAxis, AxisInfo]] = []
for ep_rank, cp_rank, tp_rank in scrambled_assignment:
tensors.append(shard_map[(ep_rank, cp_rank, tp_rank)])
parallel_infos.append(
{
ParallelAxis.EP: AxisInfo(axis_rank=ep_rank, axis_size=2),
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=2),
}
)
dim_specs = parse_dims("b e(ep) s(cp) h(tp)")
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 3
current = tensors
for plan in plans:
current = execute_unshard_plan(plan, current)
assert len(current) == 1
assert torch.allclose(current[0], full_tensor)
if __name__ == "__main__":

View File

@@ -16,12 +16,12 @@ class TestComputeUnshardPlan:
parallel_infos = [
{ParallelAxis.TP: AxisInfo(axis_rank=i, axis_size=4)} for i in range(4)
]
plan = compute_unshard_plan(dim_specs, parallel_infos)
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert plan is not None
assert plan.axis == ParallelAxis.TP
assert plan.params.dim == 2
assert plan.world_ranks_by_axis_rank == [0, 1, 2, 3]
assert len(plans) == 1
assert plans[0].axis == ParallelAxis.TP
assert plans[0].params.dim == 2
assert plans[0].groups == [[0, 1, 2, 3]]
def test_inconsistent_axis_size_raises(self) -> None:
dim_specs = parse_dims("h(tp)")
@@ -35,7 +35,7 @@ class TestComputeUnshardPlan:
def test_missing_axis_in_parallel_info_raises(self) -> None:
dim_specs = parse_dims("h(tp)")
parallel_infos = [{ParallelAxis.CP: AxisInfo(axis_rank=0, axis_size=2)}]
with pytest.raises(ValueError, match="No parallel_info found"):
with pytest.raises(ValueError, match="missing parallel_info"):
compute_unshard_plan(dim_specs, parallel_infos)
def test_empty_parallel_infos_raises(self) -> None:
@@ -52,29 +52,193 @@ class TestComputeUnshardPlan:
{ParallelAxis.TP: AxisInfo(axis_rank=3, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=4)},
]
plan = compute_unshard_plan(dim_specs, parallel_infos)
assert plan is not None
assert plan.world_ranks_by_axis_rank == [1, 3, 0, 2]
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 1
assert plans[0].groups == [[1, 3, 0, 2]]
def test_no_sharded_axes_returns_none(self) -> None:
def test_no_sharded_axes_returns_empty(self) -> None:
dim_specs = parse_dims("b s d")
parallel_infos = [{}]
plan = compute_unshard_plan(dim_specs, parallel_infos)
assert plan is None
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert plans == []
def test_multi_axis_raises(self) -> None:
dim_specs = parse_dims("h(tp) s(cp)")
def test_multi_axis_plan(self) -> None:
"""Multi-axis (TP + CP) produces a 2-step plan."""
dim_specs = parse_dims("s(cp) h(tp)")
parallel_infos = [
{
ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=2),
ParallelAxis.CP: AxisInfo(axis_rank=0, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=0, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=1, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=1, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=2),
},
]
with pytest.raises(NotImplementedError, match="Multi-axis unshard"):
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 2
assert plans[0].axis == ParallelAxis.CP
assert plans[1].axis == ParallelAxis.TP
def test_cp_tp_plan(self) -> None:
"""CP=2 + TP=4 produces correct 2-step plan with correct groups."""
dim_specs = parse_dims("s(cp) h(tp)")
parallel_infos = []
for cp_rank in range(2):
for tp_rank in range(4):
parallel_infos.append(
{
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=4),
}
)
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 2
cp_plan = plans[0]
assert cp_plan.axis == ParallelAxis.CP
assert len(cp_plan.groups) == 4
for group in cp_plan.groups:
assert len(group) == 2
tp_plan = plans[1]
assert tp_plan.axis == ParallelAxis.TP
assert len(tp_plan.groups) == 1
assert len(tp_plan.groups[0]) == 4
def test_cp_tp_scrambled_ranks(self) -> None:
"""Scrambled rank assignment still produces correct plan."""
dim_specs = parse_dims("s(cp) h(tp)")
parallel_infos = [
{
ParallelAxis.CP: AxisInfo(axis_rank=1, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=0, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=0, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=1, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=2),
},
]
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 2
cp_plan = plans[0]
assert cp_plan.axis == ParallelAxis.CP
assert len(cp_plan.groups) == 2
for group in cp_plan.groups:
assert len(group) == 2
tp_plan = plans[1]
assert tp_plan.axis == ParallelAxis.TP
assert len(tp_plan.groups) == 1
assert len(tp_plan.groups[0]) == 2
def test_axis_rank_coverage_incomplete_raises(self) -> None:
"""TP size=4 but only ranks 0,1,3 provided (missing rank 2)."""
dim_specs = parse_dims("h(tp)")
parallel_infos = [
{ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=1, axis_size=4)},
{ParallelAxis.TP: AxisInfo(axis_rank=3, axis_size=4)},
]
with pytest.raises(ValueError, match="axis_rank coverage.*incomplete"):
compute_unshard_plan(dim_specs, parallel_infos)
def test_reduction_not_implemented_raises(self) -> None:
dim_specs = parse_dims("h(tp,partial)")
parallel_infos = [
{ParallelAxis.TP: AxisInfo(axis_rank=i, axis_size=2)} for i in range(2)
]
with pytest.raises(NotImplementedError, match="reduction"):
compute_unshard_plan(dim_specs, parallel_infos)
def test_ordering_not_natural_raises(self) -> None:
dim_specs = parse_dims("s(cp,zigzag)")
parallel_infos = [
{ParallelAxis.CP: AxisInfo(axis_rank=i, axis_size=2)} for i in range(2)
]
with pytest.raises(NotImplementedError, match="ordering"):
compute_unshard_plan(dim_specs, parallel_infos)
def test_ordering_natural_accepted(self) -> None:
dim_specs = parse_dims("s(cp,natural)")
parallel_infos = [
{ParallelAxis.CP: AxisInfo(axis_rank=i, axis_size=2)} for i in range(2)
]
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 1
assert plans[0].axis == ParallelAxis.CP
def test_three_axis_plan(self) -> None:
"""EP=2 + CP=2 + TP=2 produces a 3-step plan."""
dim_specs = parse_dims("b e(ep) s(cp) h(tp)")
parallel_infos: list[dict[ParallelAxis, AxisInfo]] = []
for ep_rank in range(2):
for cp_rank in range(2):
for tp_rank in range(2):
parallel_infos.append(
{
ParallelAxis.EP: AxisInfo(axis_rank=ep_rank, axis_size=2),
ParallelAxis.CP: AxisInfo(axis_rank=cp_rank, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=tp_rank, axis_size=2),
}
)
plans = compute_unshard_plan(dim_specs, parallel_infos)
assert len(plans) == 3
assert plans[0].axis == ParallelAxis.EP
assert plans[1].axis == ParallelAxis.CP
assert plans[2].axis == ParallelAxis.TP
# Step 0 (EP): 8 tensors → 4 (groups of 2)
assert len(plans[0].groups) == 4
for group in plans[0].groups:
assert len(group) == 2
# Step 1 (CP): 4 tensors → 2 (groups of 2)
assert len(plans[1].groups) == 2
for group in plans[1].groups:
assert len(group) == 2
# Step 2 (TP): 2 tensors → 1 (single group of 2)
assert len(plans[2].groups) == 1
assert len(plans[2].groups[0]) == 2
def test_replicated_axis_raises(self) -> None:
"""A world_rank missing a sharded axis raises ValueError."""
dim_specs = parse_dims("s(cp) h(tp)")
parallel_infos = [
{
ParallelAxis.CP: AxisInfo(axis_rank=0, axis_size=2),
ParallelAxis.TP: AxisInfo(axis_rank=0, axis_size=2),
},
{
ParallelAxis.CP: AxisInfo(axis_rank=1, axis_size=2),
# missing TP — replicated
},
]
with pytest.raises(ValueError, match="missing parallel_info"):
compute_unshard_plan(dim_specs, parallel_infos)