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chore: import upstream snapshot with attribution
2026-07-13 12:55:37 +08:00

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Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""Equivalence test for ``precopy_mamba_align_fused_kernel``.
The V2 "align" pre-copy must migrate mamba state across block boundaries with
byte-identical semantics to the V1 copy specs (``get_conv_copy_spec`` /
``get_temporal_copy_spec``):
* conv state (SD layout, conv_width > 0): shift the sliding window by
``token_bias`` tokens -- ``state[bt[src_col], token_bias:]`` ->
``state[bt[dst_col], :conv_width - token_bias]``.
* temporal state (conv_width == 0): ``token_bias`` selects the accepted
speculative column -- ``state[bt[src_col + token_bias]]`` ->
``state[bt[dst_col]]``.
The kernel must also no-op when ``src_col < 0`` (fresh request) or
``src_col == dst_col`` (no boundary crossed).
"""
from __future__ import annotations
import torch
from vllm.platforms import current_platform
from vllm.v1.worker.mamba_utils import precopy_mamba_align_fused_kernel
try:
import pytest
pytestmark = pytest.mark.skipif(
not current_platform.is_cuda(),
reason="precopy_mamba_align_fused_kernel needs CUDA/Triton",
)
_parametrize = pytest.mark.parametrize
except ModuleNotFoundError: # allow running directly as ``python <thisfile>``
pytest = None
def _parametrize(_name, _values):
def _deco(fn):
return fn
return _deco
NUM_LAYERS = 3
CONV_WIDTH = 4 # conv_kernel - 1 + num_spec
CONV_DIM = 96
SSM_SHAPE = (4, 16, 16)
MAX_COLS = 8
def _build_state(num_blocks, device):
"""Per-layer (conv SD [nb, width, dim] bf16, ssm [nb, *shape] fp32) pools."""
convs, ssms = [], []
for _ in range(NUM_LAYERS):
convs.append(
torch.randn(
num_blocks, CONV_WIDTH, CONV_DIM, dtype=torch.bfloat16, device=device
)
)
ssms.append(
torch.randn(num_blocks, *SSM_SHAPE, dtype=torch.float32, device=device)
)
return convs, ssms
def _build_meta(convs, ssms, device):
"""Flattened per-(layer, state-type) metadata, ordered conv, ssm per layer."""
n = NUM_LAYERS * 2
base = torch.zeros(n, dtype=torch.int64, device=device)
blk_stride = torch.zeros(n, dtype=torch.int64, device=device)
elem = torch.zeros(n, dtype=torch.int32, device=device)
inner = torch.zeros(n, dtype=torch.int64, device=device)
width = torch.zeros(n, dtype=torch.int32, device=device)
group = torch.zeros(n, dtype=torch.int32, device=device)
drc = torch.zeros(n, dtype=torch.int32, device=device) # DS rows (unused, SD)
drs = torch.zeros(n, dtype=torch.int64, device=device)
i = 0
for layer in range(NUM_LAYERS):
conv, ssm = convs[layer], ssms[layer]
# conv (SD): width = size(1), inner = stride(1)
base[i] = conv.data_ptr()
blk_stride[i] = conv.stride(0) * conv.element_size()
elem[i] = conv.element_size()
width[i] = conv.size(1)
inner[i] = conv.stride(1)
i += 1
# ssm (temporal): width = 0, inner = elems per block
base[i] = ssm.data_ptr()
blk_stride[i] = ssm.stride(0) * ssm.element_size()
elem[i] = ssm.element_size()
width[i] = 0
inner[i] = ssm[0].numel()
i += 1
return base, blk_stride, elem, inner, width, group, drc, drs
def _reference(convs, ssms, bt, src_col, dst_col, bias, num_reqs):
"""Apply the V1 copy semantics on clones, reading from the pre-copy state."""
conv_pre = [c.clone() for c in convs]
ssm_pre = [s.clone() for s in ssms]
conv_ref = [c.clone() for c in convs]
ssm_ref = [s.clone() for s in ssms]
for r in range(num_reqs):
sc, dc, tb = int(src_col[r]), int(dst_col[r]), int(bias[r])
if sc < 0 or sc == dc:
continue
sblk, dblk = int(bt[r, sc]), int(bt[r, dc])
tblk = int(bt[r, sc + tb]) # temporal src column shifted by bias
for layer in range(NUM_LAYERS):
conv_ref[layer][dblk, : CONV_WIDTH - tb] = conv_pre[layer][sblk, tb:]
ssm_ref[layer][dblk] = ssm_pre[layer][tblk]
return conv_ref, ssm_ref
@_parametrize("num_reqs", [1, 4, 16])
@_parametrize("token_bias", [0, 1, 2])
def test_precopy_matches_v1_copy_specs(num_reqs, token_bias):
device = torch.device("cuda")
torch.manual_seed(0)
# Distinct physical block per (req, col) so copies never alias.
num_blocks = num_reqs * MAX_COLS + 1
bt = torch.empty(num_reqs, MAX_COLS, dtype=torch.int32, device=device)
for r in range(num_reqs):
bt[r] = torch.arange(
1 + r * MAX_COLS, 1 + (r + 1) * MAX_COLS, dtype=torch.int32, device=device
)
# Per-req columns: req 0 fresh (src=-1, skip), req 1 same block (skip),
# the rest cross from col 1 -> col 0 with the given spec token bias.
src_col = torch.full((num_reqs,), 1, dtype=torch.int32, device=device)
dst_col = torch.zeros(num_reqs, dtype=torch.int32, device=device)
bias = torch.full((num_reqs,), token_bias, dtype=torch.int32, device=device)
if num_reqs >= 1:
src_col[0] = -1 # fresh -> no copy
if num_reqs >= 2:
dst_col[1] = 1 # src_col == dst_col -> no copy
convs, ssms = _build_state(num_blocks, device)
conv_ref, ssm_ref = _reference(
convs, ssms, bt.cpu(), src_col.cpu(), dst_col.cpu(), bias.cpu(), num_reqs
)
base, blk_stride, elem, inner, width, group, drc, drs = _build_meta(
convs, ssms, device
)
bt_ptrs = torch.tensor([bt.data_ptr()], dtype=torch.int64, device=device)
idx_mapping = torch.arange(num_reqs, dtype=torch.int32, device=device)
grid = (num_reqs, NUM_LAYERS * 2)
precopy_mamba_align_fused_kernel[grid](
dst_col,
src_col,
bias,
bt_ptrs,
bt.stride(0),
base,
blk_stride,
elem,
inner,
width,
group,
drc,
drs,
idx_mapping,
num_reqs,
COPY_BLOCK_SIZE=1024,
CONV_STATE_DIM_FIRST=False,
)
torch.accelerator.synchronize()
for layer in range(NUM_LAYERS):
torch.testing.assert_close(convs[layer], conv_ref[layer], rtol=0, atol=0)
torch.testing.assert_close(ssms[layer], ssm_ref[layer], rtol=0, atol=0)
if __name__ == "__main__":
for nr in (1, 4, 16):
for tb in (0, 1, 2):
test_precopy_matches_v1_copy_specs(nr, tb)
print(f"OK num_reqs={nr} token_bias={tb}")