[Feature] add the magicmtp speculative decoding acceleration algorithm (#5542)

### What this PR does / why we need it?

1. MagicMTP (paper: "Block Verification Accelerates Speculative
Decoding") was introduced to consider the influence among multiple draft
tokens, improving the acceptance rate without compromising accuracy.
2. Added Triton and PyTorch implementations, and added E2E test cases.

### Does this PR introduce _any_ user-facing change?
MagicMTP will automatically take effect when the parameter
"num_speculative_tokens" >= 3.
- vLLM version: v0.13.0
- vLLM main:
7157596103

Signed-off-by: chenaoxuan <cax1165@163.com>
This commit is contained in:
Aoxuan Chen
2026-01-08 09:15:55 +08:00
committed by GitHub
parent 481138e1d2
commit 8763953f56
3 changed files with 372 additions and 37 deletions

View File

@@ -4,8 +4,11 @@ from vllm.v1.sample.rejection_sampler import \
rejection_random_sample_kernel as original_rejection_random_sample_kernel
from vllm_ascend.ops.triton.reject_sample import (
cal_grid_and_block_size, rejection_random_sample_kernel)
cal_grid_and_block_size, rejection_random_sample_block_verify_kernel,
rejection_random_sample_kernel)
from vllm_ascend.ops.triton.triton_utils import init_device_properties_triton
from vllm_ascend.sample.rejection_sampler import \
rejection_random_sample_block_verify_pytorch
@pytest.fixture(scope="function", autouse=True)
@@ -93,3 +96,134 @@ def test_rejection_random_sample(max_spec_len, vocab_size, batch_size):
BLOCK_SIZE=block_size)
torch.npu.synchronize()
assert torch.equal(original_output_token_ids, output_token_ids)
DEVICE = "npu"
BATCH_SIZE = 7
MAX_SPEC_LEN = 3
VOCAB_SIZE = 5
CU_NUM_DRAFT_TOKENS = torch.tensor([2, 2, 5, 8, 11, 14, 15],
dtype=torch.int32,
device=DEVICE)
DRAFT_TOKEN_IDS = torch.tensor([0, 1, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 2, 0],
dtype=torch.int64,
device=DEVICE)
NUM_TOKENS = DRAFT_TOKEN_IDS.shape[0]
DRAFT_PROBS = None
TARGET_PROBS = torch.tensor(
[
[0.4, 0.3, 0.1, 0.1, 0.1], # 0
[0.1, 0.9, 0.0, 0.0, 0.0], # 1
[0.2, 0.1, 0.2, 0.4, 0.1], # 0
[0.1, 0.4, 0.1, 0.1, 0.3], # 0
[0.2, 0.1, 0.4, 0.1, 0.2], # 0
[0.4, 0.2, 0.1, 0.2, 0.1], # 0
[0.1, 0.6, 0.1, 0.1, 0.1], # 1
[0.2, 0.2, 0.2, 0.3, 0.1], # 0
[0.4, 0.2, 0.1, 0.2, 0.1], # 0
[0.1, 0.6, 0.1, 0.1, 0.1], # 1
[0.2, 0.2, 0.2, 0.3, 0.1], # 0
[0.4, 0.4, 0.1, 0.0, 0.1], # 1
[0.4, 0.3, 0.1, 0.1, 0.1], # 0
[0.4, 0.0, 0.5, 0.0, 0.1], # 1
[0.4, 0.1, 0.3, 0.1, 0.1], # 1
],
dtype=torch.float32,
device=DEVICE)
UNIFORM_PROBS = torch.tensor([
0.9,
0.0,
0.9,
0.7,
0.8,
0.5,
0.45,
1.0,
0.5,
0.45,
1.0,
0.39,
0.4,
0.1,
0.3,
],
dtype=torch.float32,
device=DEVICE)
BONUS_TOKEN_IDS = torch.full((BATCH_SIZE, ),
MAX_SPEC_LEN + 1,
dtype=torch.int64,
device=DEVICE)
RECOVERED_TOKEN_IDS = torch.full((NUM_TOKENS, ),
MAX_SPEC_LEN,
dtype=torch.int64,
device=DEVICE)
IS_GREEDY = torch.zeros(BATCH_SIZE, dtype=torch.bool, device=DEVICE)
IS_GREEDY[4] = True
@pytest.mark.parametrize("cu_num_draft_tokens", [CU_NUM_DRAFT_TOKENS])
@pytest.mark.parametrize("draft_token_ids", [DRAFT_TOKEN_IDS])
@pytest.mark.parametrize("draft_probs", [DRAFT_PROBS])
@pytest.mark.parametrize("target_probs", [TARGET_PROBS])
@pytest.mark.parametrize("bonus_token_ids", [BONUS_TOKEN_IDS])
@pytest.mark.parametrize("recovered_token_ids", [RECOVERED_TOKEN_IDS])
@pytest.mark.parametrize("uniform_probs", [UNIFORM_PROBS])
@pytest.mark.parametrize("is_greedy", [IS_GREEDY])
@pytest.mark.parametrize("batch_size", [BATCH_SIZE])
@pytest.mark.parametrize("max_spec_len", [MAX_SPEC_LEN])
@pytest.mark.parametrize("vocab_size", [VOCAB_SIZE])
@torch.inference_mode()
def test_rejection_sampler_block_verify_triton_kernel(
cu_num_draft_tokens, # [batch_size]
draft_token_ids, # [num_tokens]
draft_probs, # [num_tokens, vocab_size] or None
target_probs, # [num_tokens, vocab_size]
bonus_token_ids, # [batch_size]
recovered_token_ids, # [num_tokens]
uniform_probs, # [num_tokens]
is_greedy, # [batch_size]
batch_size, # int
max_spec_len, # int
vocab_size, # int
) -> None:
grid, block_size = cal_grid_and_block_size(batch_size)
output_token_ids_ref = torch.full((batch_size, max_spec_len + 1),
-1,
dtype=torch.int64,
device=DEVICE)
output_token_ids_triton = output_token_ids_ref.clone()
rejection_random_sample_block_verify_pytorch(
output_token_ids=output_token_ids_ref,
cu_num_draft_tokens=cu_num_draft_tokens,
draft_token_ids=draft_token_ids,
draft_probs=draft_probs,
target_probs=target_probs,
bonus_token_ids=bonus_token_ids,
recovered_token_ids=recovered_token_ids,
uniform_probs=uniform_probs,
is_greedy=is_greedy,
max_spec_len=max_spec_len,
vocab_size=vocab_size,
IS_NGRAM=draft_probs is None)
rejection_random_sample_block_verify_kernel[(grid, )](
output_token_ids_ptr=output_token_ids_triton,
cu_num_draft_tokens_ptr=cu_num_draft_tokens,
draft_token_ids_ptr=draft_token_ids,
draft_probs_ptr=draft_probs,
target_probs_ptr=target_probs,
bonus_token_ids_ptr=bonus_token_ids,
recovered_token_ids_ptr=recovered_token_ids,
uniform_probs_ptr=uniform_probs,
is_greedy_ptr=is_greedy,
max_spec_len=max_spec_len,
vocab_size=vocab_size,
vec_len=batch_size,
NO_DRAFT_PROBS=draft_probs is None,
BLOCK_SIZE=block_size)
torch.npu.synchronize()
assert torch.equal(output_token_ids_ref, output_token_ids_triton)