[Cleanup] Remove obsolete spec decoding compatibility logic (#32003)

Signed-off-by: Nick Hill <nickhill123@gmail.com>

benchmarks/benchmark_ngram_proposer.py

@@ -135,7 +135,6 @@ def benchmark_batched_propose(args):
             block_sizes=[16],
         )
         dummy_input_batch._req_ids = list(str(id) for id in range(args.num_req))
-        dummy_input_batch.spec_decode_unsupported_reqs = ()
         dummy_input_batch.num_tokens_no_spec = [args.num_token] * args.num_req
         dummy_input_batch.token_ids_cpu = np.random.randint(
             0, 20, (args.num_req, args.num_token)
@@ -151,10 +150,8 @@ def benchmark_batched_propose(args):
             start = time.time()
             runner.drafter.propose(
                 sampled_token_ids,
-                dummy_input_batch.req_ids,
                 dummy_input_batch.num_tokens_no_spec,
                 dummy_input_batch.token_ids_cpu,
-                dummy_input_batch.spec_decode_unsupported_reqs,
             )
             end = time.time()
             print(f"Iteration time (s): {end - start}")

tests/v1/sample/test_logprobs.py

@@ -940,27 +940,62 @@ def test_correct_decoded_token_preserves_valid_tokens():
             (
                 "eagle",
                 "meta-llama/Llama-3.2-1B-Instruct",
-                "nm-testing/Llama3_2_1B_speculator.eagle3",
+                {
+                    "method": "eagle",
+                    "model": "nm-testing/Llama3_2_1B_speculator.eagle3",
+                    "num_speculative_tokens": 3,
+                },
+                0,
             ),
             marks=large_gpu_mark(min_gb=32),
+            id="eagle0",
+        ),
+        pytest.param(
+            (
+                "eagle",
+                "meta-llama/Llama-3.2-1B-Instruct",
+                {
+                    "method": "eagle",
+                    "model": "nm-testing/Llama3_2_1B_speculator.eagle3",
+                    "num_speculative_tokens": 3,
+                },
+                3,
+            ),
+            marks=large_gpu_mark(min_gb=32),
+            id="eagle3",
+        ),
+        pytest.param(
+            (
+                "ngram",
+                "meta-llama/Llama-3.2-1B-Instruct",
+                {
+                    "method": "ngram",
+                    "prompt_lookup_max": 5,
+                    "prompt_lookup_min": 3,
+                    "num_speculative_tokens": 3,
+                },
+                3,
+            ),
+            marks=large_gpu_mark(min_gb=32),
+            id="ngram",
         ),
     ],
 )
-@pytest.mark.parametrize("top_logprobs", [0, 3])
 def test_spec_decode_logprobs(
     logprobs_mode: LogprobsMode,
-    model_setup: tuple[str, str, str],
+    model_setup: tuple[str, str, dict, int],
-    top_logprobs: int,
 ):
     """Spec decode logprobs should match those of the base model.
 
     Args:
         logprobs_mode: logprobs mode.
-        model_setup: Spec decode method, base model name, and
+        model_setup: Tuple of (method, base model name,
-        draft model name.
+            speculative_config dict, top_logprobs).
     """
     from vllm import LLM
 
+    method, model_name, spec_config, top_logprobs = model_setup
+
     prompt = "Hello world " * 50
     sampling_params = SamplingParams(
         temperature=0, logprobs=top_logprobs, max_tokens=10, ignore_eos=False
@@ -972,7 +1007,7 @@ def test_spec_decode_logprobs(
         ignore_eos=False,
         presence_penalty=-1.0,
     )
-    method, model_name, spec_model_name = model_setup
+
     max_model_len = 256
 
     # Run base LLM.
@@ -999,14 +1034,11 @@ def test_spec_decode_logprobs(
     cleanup_dist_env_and_memory()
 
     # Run spec decode LLM.
+    # Add max_model_len to spec_config if not present
+    spec_config_with_len = {**spec_config, "max_model_len": max_model_len}
     spec_llm = LLM(
         model_name,
-        speculative_config={
+        speculative_config=spec_config_with_len,
-            "method": method,
-            "model": spec_model_name,
-            "num_speculative_tokens": 3,
-            "max_model_len": max_model_len,
-        },
         max_logprobs=5,
         max_model_len=max_model_len,
         seed=42,

tests/v1/spec_decode/test_ngram.py

@@ -82,10 +82,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[1, 2, 3, 4, 5]])
     result = get_ngram_proposer(min_n=2, max_n=2, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert len(result[0]) == 0
 
@@ -93,10 +91,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[1, 2, 3, 4, 1, 2, 3]])
     result = get_ngram_proposer(min_n=4, max_n=4, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert len(result[0]) == 0
 
@@ -104,10 +100,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[1, 2, 3, 4, 1, 2, 3]])
     result = get_ngram_proposer(min_n=3, max_n=4, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert np.array_equal(result, np.array([[4, 1]]))
 
@@ -116,10 +110,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[2, 3, 4, 5, 1, 2, 3, 4, 1, 2, 3, 4]])
     result = get_ngram_proposer(min_n=3, max_n=4, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert np.array_equal(result, np.array([[1, 2]]))  # Not [5, 1]]
 
@@ -127,10 +119,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[3, 4, 5, 2, 3, 4, 1, 2, 3, 4]])
     result = get_ngram_proposer(min_n=2, max_n=4, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert np.array_equal(result, np.array([[1, 2]]))  # Not [5, 2]]
 
@@ -138,10 +128,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[1, 2, 3, 100, 1, 2, 3, 200, 1, 2, 3, 300, 1, 2, 3]])
     result = get_ngram_proposer(min_n=3, max_n=3, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert np.array_equal(result, np.array([[100, 1]]))
 
@@ -149,10 +137,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[]])
     result = get_ngram_proposer(min_n=2, max_n=2, k=2).propose(
         sampled_token_ids=[[0]],
-        req_ids=["0"],
         num_tokens_no_spec=np.array([len(c) for c in token_ids_cpu]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert len(result[0]) == 0
 
@@ -162,10 +148,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([[1, 2, 3, 1, 2], [4, 5, 6, -1, -1]])
     result = get_ngram_proposer(min_n=2, max_n=2, k=2).propose(
         sampled_token_ids=[[0], [1]],
-        req_ids=["0", "1"],
         num_tokens_no_spec=np.array([5, 3]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert len(result[0]) == 2
     assert np.array_equal(result[0], np.array([3, 1]))
@@ -183,10 +167,8 @@ def test_ngram_proposer():
     sampled_token_ids = [[2], [], [8]]  # Empty list for request 1 simulates prefill
     result = proposer.propose(
         sampled_token_ids=sampled_token_ids,
-        req_ids=["0", "1", "2"],
         num_tokens_no_spec=num_tokens_no_spec,
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert len(result) == 3
     assert np.array_equal(result[0], [3, 1])
@@ -214,10 +196,8 @@ def test_ngram_proposer():
     token_ids_cpu = np.array([input_1, input_2])
     result = ngram_proposer.propose(
         sampled_token_ids=[[0], [1]],
-        req_ids=["0", "1"],
         num_tokens_no_spec=np.array([len(input_1), 3]),
         token_ids_cpu=token_ids_cpu,
-        spec_decode_unsupported_reqs=(),
     )
     assert len(result[0]) == 2
     assert np.array_equal(result[0], np.array([middle_integer + 2, middle_integer + 3]))

vllm/v1/spec_decode/ngram_proposer.py

@@ -55,10 +55,8 @@ class NgramProposer:
         # This usually takes less than 1 second.
         self.propose(
             [[]] * 1024,
-            [""] * 1024,
             np.zeros(1024, dtype=np.int32),
             np.zeros((1024, self.max_model_len), dtype=np.int32),
-            set(),
         )
 
     def batch_propose(
@@ -132,10 +130,8 @@ class NgramProposer:
     def propose(
         self,
         sampled_token_ids: list[list[int]],
-        req_ids: list[str],
         num_tokens_no_spec: np.ndarray,
         token_ids_cpu: np.ndarray,
-        spec_decode_unsupported_reqs: set,
     ) -> list[list[int]]:
         # find which requests need ngram proposals
         valid_ngram_requests = []
@@ -145,12 +141,6 @@ class NgramProposer:
                 # Skip speculative decoding.
                 continue
 
-            # Skip requests that require sampling parameters that are not
-            # supported with speculative decoding.
-            req_id = req_ids[i]
-            if req_id in spec_decode_unsupported_reqs:
-                continue
-
             num_tokens = num_tokens_no_spec[i]
             if num_tokens >= self.max_model_len:
                 # Skip requests that have already reached the max model length.

vllm/v1/spec_decode/suffix_decoding.py

@@ -46,13 +46,7 @@ class SuffixDecodingProposer:
                 draft_token_ids.append([])
                 continue
 
-            # Skip requests that require sampling parameters that are not
-            # supported with speculative decoding.
             req_id = input_batch.req_ids[i]
-            if req_id in input_batch.spec_decode_unsupported_reqs:
-                draft_token_ids.append([])
-                continue
-
             num_tokens = input_batch.num_tokens_no_spec[i]
             if num_tokens >= self.max_model_len:
                 # Skip requests that have already reached the max model length.

vllm/v1/spec_decode/utils.py

@@ -1,21 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
-from vllm.sampling_params import SamplingParams
 from vllm.triton_utils import tl, triton
 
-_SAMPLING_EPS = 1e-5
-
-
-def is_spec_decode_unsupported(sampling_params: SamplingParams) -> bool:
-    """True if request is incompatible with speculative decoding"""
-    return (
-        sampling_params.frequency_penalty != 0.0
-        or sampling_params.presence_penalty != 0.0
-        or sampling_params.repetition_penalty != 1.0
-        or sampling_params.min_p > _SAMPLING_EPS
-        or sampling_params.logprobs is not None
-    )
-
 
 @triton.jit
 def eagle_prepare_inputs_padded_kernel(

vllm/v1/worker/gpu_input_batch.py

@@ -22,7 +22,6 @@ from vllm.v1.sample.logits_processor import (
     MoveDirectionality,
 )
 from vllm.v1.sample.metadata import SamplingMetadata
-from vllm.v1.spec_decode.utils import is_spec_decode_unsupported
 from vllm.v1.utils import copy_slice
 from vllm.v1.worker.block_table import MultiGroupBlockTable
 
@@ -176,9 +175,6 @@ class InputBatch:
         self.top_k_cpu = self.top_k_cpu_tensor.numpy()
         self.top_k_reqs: set[str] = set()
 
-        # IDs of requests which do not support spec decoding
-        self.spec_decode_unsupported_reqs: set[str] = set()
-
         # Frequency penalty related data structures
         self.frequency_penalties = torch.empty(
             (max_num_reqs,), dtype=torch.float, device=device
@@ -346,8 +342,6 @@ class InputBatch:
         self.block_table.add_row(request.block_ids, req_index)
 
         if sampling_params := request.sampling_params:
-            if self.is_spec_decode and is_spec_decode_unsupported(sampling_params):
-                self.spec_decode_unsupported_reqs.add(req_id)
             if sampling_params.sampling_type == SamplingType.GREEDY:
                 # Should avoid division by zero later when apply_temperature.
                 self.temperature_cpu[req_index] = 0.0
@@ -510,7 +504,6 @@ class InputBatch:
         self.random_reqs.discard(req_id)
         self.top_p_reqs.discard(req_id)
         self.top_k_reqs.discard(req_id)
-        self.spec_decode_unsupported_reqs.discard(req_id)
         self.frequency_penalties_reqs.discard(req_id)
         self.presence_penalties_reqs.discard(req_id)
         self.repetition_penalties_reqs.discard(req_id)

vllm/v1/worker/gpu_model_runner.py

@@ -3620,10 +3620,8 @@ class GPUModelRunner(
             assert isinstance(self.drafter, NgramProposer)
             draft_token_ids = self.drafter.propose(
                 sampled_token_ids,
-                self.input_batch.req_ids,
                 self.input_batch.num_tokens_no_spec,
                 self.input_batch.token_ids_cpu,
-                self.input_batch.spec_decode_unsupported_reqs,
             )
         elif spec_config.method == "suffix":
             assert isinstance(sampled_token_ids, list)