| 1 | # SPDX-License-Identifier: Apache-2.0 |
| 2 | # SPDX-FileCopyrightText: Copyright contributors to the vLLM project |
| 3 | |
| 4 | """E2E tests for ``thinking_token_budget`` with reasoning models. |
| 5 | |
| 6 | Covers Qwen3-0.6B and Qwen3.5 FP8 + MTP. |
| 7 | """ |
| 8 | |
| 9 | import asyncio |
| 10 | import json |
| 11 | from typing import Literal |
| 12 | |
| 13 | import openai |
| 14 | import pytest |
| 15 | import pytest_asyncio |
| 16 | |
| 17 | from tests.utils import RemoteOpenAIServer, multi_gpu_only, requires_fp8 |
| 18 | from vllm.platforms import current_platform |
| 19 | from vllm.tokenizers import get_tokenizer |
| 20 | |
| 21 | MODEL_NAME = "Qwen/Qwen3-0.6B" |
| 22 | QWEN35_FP8_MTP_MODEL = "Qwen/Qwen3.5-35B-A3B-FP8" |
| 23 | MESSAGES = [{"role": "user", "content": "What is 1+1? Be concise."}] |
| 24 | THINK_BUDGET = 5 |
| 25 | |
| 26 | REASONING_START_STR = "<think>" |
| 27 | REASONING_END_STR = "</think>" |
| 28 | |
| 29 | |
| 30 | def _count_reasoning_decode_token_ids_between_markers( |
| 31 | full_token_ids: list[int], |
| 32 | reasoning_start_ids: list[int], |
| 33 | reasoning_end_ids: list[int], |
| 34 | ) -> int | None: |
| 35 | """Count decode tokens in the thinking span (after last start, before first end).""" |
| 36 | if not reasoning_start_ids or not reasoning_end_ids: |
| 37 | raise ValueError("reasoning marker token id lists must be non-empty") |
| 38 | |
| 39 | def _last_subseq_index(haystack: list[int], needle: list[int]) -> int: |
| 40 | n = len(needle) |
| 41 | if n > len(haystack): |
| 42 | return -1 |
| 43 | for i in range(len(haystack) - n, -1, -1): |
| 44 | if haystack[i : i + n] == needle: |
| 45 | return i |
| 46 | return -1 |
| 47 | |
| 48 | last_start = _last_subseq_index(full_token_ids, reasoning_start_ids) |
| 49 | if last_start < 0: |
| 50 | return None |
| 51 | |
| 52 | pos_after_start = last_start + len(reasoning_start_ids) |
| 53 | end_n = len(reasoning_end_ids) |
| 54 | for j in range(pos_after_start, len(full_token_ids) - end_n + 1): |
| 55 | if full_token_ids[j : j + end_n] == reasoning_end_ids: |
| 56 | return j - pos_after_start |
| 57 | return len(full_token_ids) - pos_after_start |
| 58 | |
| 59 | |
| 60 | @pytest.fixture(scope="module") |
| 61 | def server(): |
| 62 | args = [ |
| 63 | "--reasoning-parser", |
| 64 | "qwen3", |
| 65 | "--reasoning-config", |
| 66 | '{"reasoning_start_str": "<think>", "reasoning_end_str": "</think>"}', |
| 67 | "--max-model-len", |
| 68 | "2048", |
| 69 | "--enforce-eager", |
| 70 | "--gpu-memory-utilization", |
| 71 | "0.4", |
| 72 | "--no-async-scheduling", |
| 73 | ] |
| 74 | with RemoteOpenAIServer(MODEL_NAME, args) as remote_server: |
| 75 | yield remote_server |
| 76 | |
| 77 | |
| 78 | @pytest.fixture(scope="module") |
| 79 | def server_with_auto_reasoning_config(): |
| 80 | args = [ |
| 81 | "--reasoning-parser", |
| 82 | "qwen3", |
| 83 | "--max-model-len", |
| 84 | "2048", |
| 85 | "--enforce-eager", |
| 86 | "--gpu-memory-utilization", |
| 87 | "0.4", |
| 88 | "--no-async-scheduling", |
| 89 | ] |
| 90 | with RemoteOpenAIServer(MODEL_NAME, args) as remote_server: |
| 91 | yield remote_server |
| 92 | |
| 93 | |
| 94 | @pytest.fixture(scope="module") |
| 95 | def server_qwen35_fp8_mtp_tp2(): |
| 96 | """Qwen3.5-35B FP8 with MTP speculative decoding and tensor parallel size 2.""" |
| 97 | if current_platform.device_count() < 2: |
| 98 | pytest.skip("Need at least 2 GPUs for --tensor-parallel-size 2") |
| 99 | if not current_platform.supports_fp8(): |
| 100 | pytest.skip("FP8 is not supported on this platform") |
| 101 | |
| 102 | spec_cfg = { |
| 103 | "method": "mtp", |
| 104 | "num_speculative_tokens": 2, |
| 105 | "max_model_len": 32768, |
| 106 | } |
| 107 | args = [ |
| 108 | "--tensor-parallel-size", |
| 109 | "2", |
| 110 | "--max-model-len", |
| 111 | "32768", |
| 112 | "--speculative-config", |
| 113 | json.dumps(spec_cfg), |
| 114 | "--reasoning-parser", |
| 115 | "qwen3", |
| 116 | "--reasoning-config", |
| 117 | json.dumps( |
| 118 | { |
| 119 | "reasoning_start_str": REASONING_START_STR, |
| 120 | "reasoning_end_str": REASONING_END_STR, |
| 121 | } |
| 122 | ), |
| 123 | ] |
| 124 | env_dict: dict[str, str] = {} |
| 125 | # With 4+ GPUs, run TP=2 on physical devices 2,3 so module-scoped 0.6B servers |
| 126 | # on 0,1 do not exhaust memory on the same devices as this worker. |
| 127 | if current_platform.device_count() >= 4: |
| 128 | env_dict["CUDA_VISIBLE_DEVICES"] = "2,3" |
| 129 | |
| 130 | with RemoteOpenAIServer( |
| 131 | QWEN35_FP8_MTP_MODEL, |
| 132 | args, |
| 133 | max_wait_seconds=3000, |
| 134 | env_dict=env_dict, |
| 135 | ) as remote_server: |
| 136 | yield remote_server |
| 137 | |
| 138 | |
| 139 | @pytest_asyncio.fixture |
| 140 | async def client(request, server, server_with_auto_reasoning_config): |
| 141 | server_map = { |
| 142 | "default": server, |
| 143 | "auto_config": server_with_auto_reasoning_config, |
| 144 | } |
| 145 | target_server = server_map[request.param] |
| 146 | async with target_server.get_async_client() as async_client: |
| 147 | yield async_client |
| 148 | |
| 149 | |
| 150 | @pytest.mark.asyncio |
| 151 | @pytest.mark.parametrize("client", ["default", "auto_config"], indirect=True) |
| 152 | async def test_thinking_token_budget_mixed_requests(client: openai.AsyncOpenAI): |
| 153 | """Test that mixed requests (some with thinking_token_budget, some without) |
| 154 | complete successfully without errors.""" |
| 155 | response_with_budget = await client.chat.completions.create( |
| 156 | model=MODEL_NAME, |
| 157 | messages=MESSAGES, |
| 158 | max_tokens=100, |
| 159 | extra_body={"thinking_token_budget": THINK_BUDGET}, |
| 160 | ) |
| 161 | response_without_budget = await client.chat.completions.create( |
| 162 | model=MODEL_NAME, |
| 163 | messages=MESSAGES, |
| 164 | max_tokens=100, |
| 165 | ) |
| 166 | |
| 167 | msg_with = response_with_budget.choices[0].message |
| 168 | msg_without = response_without_budget.choices[0].message |
| 169 | |
| 170 | assert msg_with.content or getattr(msg_with, "reasoning", None) |
| 171 | assert msg_without.content or getattr(msg_without, "reasoning", None) |
| 172 | |
| 173 | |
| 174 | @pytest.mark.asyncio |
| 175 | @pytest.mark.parametrize("client", ["default", "auto_config"], indirect=True) |
| 176 | async def test_thinking_token_budget_limits_reasoning(client: openai.AsyncOpenAI): |
| 177 | """Test that thinking_token_budget limits the number of reasoning tokens. |
| 178 | |
| 179 | Counts reasoning decode tokens by id, which is robust to how tokens are |
| 180 | grouped into streamed chunks (a single chunk can carry several tokens under |
| 181 | async scheduling / stream_interval > 1). Counting chunks under-counts. |
| 182 | """ |
| 183 | tokenizer = get_tokenizer(tokenizer_name=MODEL_NAME) |
| 184 | start_ids = list(tokenizer.encode(REASONING_START_STR, add_special_tokens=False)) |
| 185 | end_ids = list(tokenizer.encode(REASONING_END_STR, add_special_tokens=False)) |
| 186 | |
| 187 | prompt_token_ids: list[int] = [] |
| 188 | decode_token_ids: list[int] = [] |
| 189 | stream = await client.chat.completions.create( |
| 190 | model=MODEL_NAME, |
| 191 | messages=MESSAGES, |
| 192 | max_tokens=100, |
| 193 | stream=True, |
| 194 | extra_body={"thinking_token_budget": THINK_BUDGET, "return_token_ids": True}, |
| 195 | ) |
| 196 | async for chunk in stream: |
| 197 | if not chunk.choices: |
| 198 | continue |
| 199 | if getattr(chunk, "prompt_token_ids", None): |
| 200 | prompt_token_ids = list(chunk.prompt_token_ids) |
| 201 | delta_ids = getattr(chunk.choices[0], "token_ids", None) |
| 202 | if delta_ids: |
| 203 | decode_token_ids.extend(delta_ids) |
| 204 | |
| 205 | reasoning_token_count = _count_reasoning_decode_token_ids_between_markers( |
| 206 | prompt_token_ids + decode_token_ids, start_ids, end_ids |
| 207 | ) |
| 208 | assert reasoning_token_count is not None, "missing reasoning start marker in ids" |
| 209 | assert reasoning_token_count == THINK_BUDGET, ( |
| 210 | f"reasoning tokens ({reasoning_token_count}) != " |
| 211 | f"thinking_token_budget ({THINK_BUDGET})" |
| 212 | ) |
| 213 | |
| 214 | |
| 215 | @pytest.mark.asyncio |
| 216 | @multi_gpu_only(num_gpus=2) |
| 217 | @requires_fp8 |
| 218 | async def test_thinking_token_budget_qwen35_fp8_mtp_concurrent_mixed_budget_and_plain( |
| 219 | server_qwen35_fp8_mtp_tp2, |
| 220 | ): |
| 221 | """Concurrent chat requests: some with ``thinking_token_budget``, some without. |
| 222 | |
| 223 | Exercises the scheduler / input processor under a mixed batch on the same |
| 224 | Qwen3.5 FP8 + MTP (TP=2) server. Budgeted calls are checked with |
| 225 | ``_count_reasoning_decode_token_ids_between_markers`` on full token ids. |
| 226 | """ |
| 227 | _batch_spec: list[tuple[Literal["budget"], int] | tuple[Literal["plain"], None]] = [ |
| 228 | ("budget", 1), |
| 229 | ("budget", 12), |
| 230 | ("plain", None), |
| 231 | ("budget", 20), |
| 232 | ("budget", 14), |
| 233 | ("plain", None), |
| 234 | ("plain", None), |
| 235 | ("budget", 12), |
| 236 | ("plain", None), |
| 237 | ] |
| 238 | |
| 239 | tokenizer = get_tokenizer(tokenizer_name=QWEN35_FP8_MTP_MODEL) |
| 240 | start_ids = list(tokenizer.encode(REASONING_START_STR, add_special_tokens=False)) |
| 241 | end_ids = list(tokenizer.encode(REASONING_END_STR, add_special_tokens=False)) |
| 242 | |
| 243 | async with server_qwen35_fp8_mtp_tp2.get_async_client() as client: |
| 244 | |
| 245 | async def budgeted_call(expected_budget: int): |
| 246 | return await client.chat.completions.create( |
| 247 | model=QWEN35_FP8_MTP_MODEL, |
| 248 | messages=MESSAGES, |
| 249 | max_tokens=256, |
| 250 | stream=False, |
| 251 | extra_body={ |
| 252 | "thinking_token_budget": expected_budget, |
| 253 | "return_token_ids": True, |
| 254 | }, |
| 255 | ) |
| 256 | |
| 257 | async def plain_call(): |
| 258 | return await client.chat.completions.create( |
| 259 | model=QWEN35_FP8_MTP_MODEL, |
| 260 | messages=MESSAGES, |
| 261 | max_tokens=256, |
| 262 | stream=False, |
| 263 | ) |
| 264 | |
| 265 | coros = [] |
| 266 | for row in _batch_spec: |
| 267 | if row[0] == "budget": |
| 268 | b = row[1] |
| 269 | assert isinstance(b, int) |
| 270 | coros.append(budgeted_call(b)) |
| 271 | else: |
| 272 | coros.append(plain_call()) |
| 273 | results = await asyncio.gather(*coros) |
| 274 | |
| 275 | for i, (response, (kind, expected_budget)) in enumerate( |
| 276 | zip(results, _batch_spec, strict=True) |
| 277 | ): |
| 278 | msg = response.choices[0].message |
| 279 | assert msg.content or getattr(msg, "reasoning", None), ( |
| 280 | f"index {i} ({kind}): empty message" |
| 281 | ) |
| 282 | |
| 283 | if kind == "budget": |
| 284 | assert expected_budget is not None |
| 285 | assert response.prompt_token_ids is not None |
| 286 | assert response.choices[0].token_ids is not None |
| 287 | full_ids = list(response.prompt_token_ids) + list( |
| 288 | response.choices[0].token_ids |
| 289 | ) |
| 290 | n_reason = _count_reasoning_decode_token_ids_between_markers( |
| 291 | full_ids, start_ids, end_ids |
| 292 | ) |
| 293 | assert n_reason is not None, f"index {i}: missing reasoning start in ids" |
| 294 | assert n_reason == expected_budget, ( |
| 295 | f"index {i}: reasoning decode token ids ({n_reason}) != " |
| 296 | f"thinking_token_budget ({expected_budget})" |
| 297 | ) |
| 298 | |
| 299 | |
| 300 | @pytest.mark.asyncio |
| 301 | @pytest.mark.parametrize("client", ["default", "auto_config"], indirect=True) |
| 302 | async def test_streaming_with_thinking_disabled_stays_in_content( |
| 303 | client: openai.AsyncOpenAI, |
| 304 | ): |
| 305 | request_kwargs = { |
| 306 | "model": MODEL_NAME, |
| 307 | "messages": [ |
| 308 | { |
| 309 | "role": "user", |
| 310 | "content": "Which is larger, 4 or 12?" |
| 311 | " Output exactly one token: 4 or 12.", |
| 312 | } |
| 313 | ], |
| 314 | "max_tokens": 16, |
| 315 | "temperature": 0.0, |
| 316 | "extra_body": {"chat_template_kwargs": {"enable_thinking": False}}, |
| 317 | } |
| 318 | |
| 319 | response = await client.chat.completions.create(**request_kwargs) |
| 320 | message = response.choices[0].message |
| 321 | assert message.content is not None and message.content.strip() != "" |
| 322 | assert getattr(message, "reasoning", None) in (None, "") |
| 323 | |
| 324 | stream = await client.chat.completions.create( |
| 325 | **request_kwargs, |
| 326 | stream=True, |
| 327 | ) |
| 328 | |
| 329 | content_chunks = [] |
| 330 | reasoning_chunks = [] |
| 331 | async for chunk in stream: |
| 332 | if not chunk.choices: |
| 333 | continue |
| 334 | delta = chunk.choices[0].delta |
| 335 | if getattr(delta, "content", None): |
| 336 | content_chunks.append(delta.content) |
| 337 | if getattr(delta, "reasoning", None): |
| 338 | reasoning_chunks.append(delta.reasoning) |
| 339 | |
| 340 | assert "".join(content_chunks).strip() != "" |
| 341 | assert reasoning_chunks == [] |