[Config] Clean up SchedulerConfig initialization

tests/models/language/generation/test_hybrid.py

@@ -348,9 +348,14 @@ def test_fp32_cache_state(
 
 
 # Helper functions for the APC tests
-def _get_vllm_runner_params(model, max_model_len, tensor_parallel_size=1):
+def _get_vllm_runner_params(
+    model: str,
+    max_model_len: int,
+    tensor_parallel_size: int = 1,
+):
     return {
         "model_name": model,
+        "enable_chunked_prefill": True,
         "enable_prefix_caching": False,
         "max_model_len": max_model_len,
         "tensor_parallel_size": tensor_parallel_size,

tests/v1/core/test_scheduler.py

@@ -2256,6 +2256,8 @@ def test_chunked_prefill_disabled_for_encoder_decoder(
     scheduler_config = SchedulerConfig(
         enable_chunked_prefill=enable_chunked_prefill,
         is_encoder_decoder=is_encoder_decoder,
+        # Must <= max_num_batched_tokens if chunked prefill is disabled
+        max_model_len=SchedulerConfig.DEFAULT_MAX_NUM_BATCHED_TOKENS,
     )
 
     # `is_encoder_decoder` should only be used during construction

tests/v1/sample/test_logprobs.py

@@ -47,6 +47,7 @@ def vllm_model(vllm_runner, request) -> Generator[VllmRunner, None, None]:
         max_num_batched_tokens=16,
         max_num_seqs=16,
         max_model_len=128,
+        enable_chunked_prefill=True,
         enforce_eager=True,
         # TODO: enable this once we support it for
         # prompt logprobs.

vllm/config/scheduler.py

@@ -4,19 +4,14 @@
 import hashlib
 from collections.abc import Callable
 from dataclasses import InitVar
-from typing import TYPE_CHECKING, Any, Literal, cast
+from typing import TYPE_CHECKING, Any, ClassVar, Literal, cast
 
 from pydantic import Field, field_validator, model_validator
 from pydantic.dataclasses import dataclass
 from typing_extensions import Self
 
 from vllm.config.utils import config
 from vllm.logger import init_logger
-from vllm.utils import (
-    DEFAULT_MAX_NUM_BATCHED_TOKENS,
-    MULTIMODAL_MODEL_MAX_NUM_BATCHED_TOKENS,
-    POOLING_MODEL_MAX_NUM_BATCHED_TOKENS,
-)
 from vllm.utils.import_utils import resolve_obj_by_qualname
 
 if TYPE_CHECKING:
@@ -33,25 +28,32 @@
 class SchedulerConfig:
     """Scheduler configuration."""
 
+    DEFAULT_MAX_NUM_BATCHED_TOKENS: ClassVar[int] = 2048
+    DEFAULT_MAX_NUM_SEQS: ClassVar[int] = 128
+
     runner_type: RunnerType = "generate"
     """The runner type to launch for the model."""
 
-    max_num_batched_tokens: int = Field(default=None, ge=1)
+    max_num_batched_tokens: int = Field(default=DEFAULT_MAX_NUM_BATCHED_TOKENS, ge=1)
     """Maximum number of tokens to be processed in a single iteration.
 
-    This config has no static default. If left unspecified by the user, it will
-    be set in `EngineArgs.create_engine_config` based on the usage context."""
+    The default value here is mainly for convenience when testing.
+    In real usage, this should be set in `EngineArgs.create_engine_config`.
+    """
 
-    max_num_seqs: int = Field(default=None, ge=1)
+    max_num_seqs: int = Field(default=DEFAULT_MAX_NUM_SEQS, ge=1)
     """Maximum number of sequences to be processed in a single iteration.
 
-    This config has no static default. If left unspecified by the user, it will
-    be set in `EngineArgs.create_engine_config` based on the usage context."""
+    The default value here is mainly for convenience when testing.
+    In real usage, this should be set in `EngineArgs.create_engine_config`.
+    """
 
-    max_model_len: int = Field(default=None, ge=1)
-    """Maximum length of a sequence (including prompt and generated text). This
-    is primarily set in `ModelConfig` and that value should be manually
-    duplicated here."""
+    max_model_len: int = Field(default=8192, ge=1)
+    """Maximum length of a sequence (including prompt and generated text).
+
+    The default value here is mainly for convenience when testing.
+    In real usage, this should duplicate `ModelConfig.max_model_len` via
+    `EngineArgs`."""
 
     max_num_partial_prefills: int = Field(default=1, ge=1)
     """For chunked prefill, the maximum number of sequences that can be
@@ -76,9 +78,13 @@ class SchedulerConfig:
     NOTE: This will be replaced by speculative config in the future; it is
     present to enable correctness tests until then."""
 
-    enable_chunked_prefill: bool = Field(default=None)
+    enable_chunked_prefill: bool = True
     """If True, prefill requests can be chunked based
-    on the remaining max_num_batched_tokens."""
+    on the remaining `max_num_batched_tokens`.
+
+    The default value here is mainly for convenience when testing.
+    In real usage, this should be set in `EngineArgs.create_engine_config`.
+    """
 
     is_multimodal_model: bool = False
     """True if the model is multimodal."""
@@ -111,9 +117,6 @@ class SchedulerConfig:
     - "priority" means requests are handled based on given priority (lower
     value means earlier handling) and time of arrival deciding any ties)."""
 
-    chunked_prefill_enabled: bool = Field(init=False)
-    """True if chunked prefill is enabled."""
-
     disable_chunked_mm_input: bool = False
     """If set to true and chunked prefill is enabled, we do not want to
     partially schedule a multimodal item. Only used in V1
@@ -188,15 +191,7 @@ def compute_hash(self) -> str:
         hash_str = hashlib.md5(str(factors).encode(), usedforsecurity=False).hexdigest()
         return hash_str
 
-    @field_validator(
-        "max_num_batched_tokens",
-        "max_num_seqs",
-        "max_model_len",
-        "enable_chunked_prefill",
-        "scheduler_cls",
-        "async_scheduling",
-        mode="wrap",
-    )
+    @field_validator("scheduler_cls", "async_scheduling", mode="wrap")
     @classmethod
     def _skip_none_validation(cls, value: Any, handler: Callable) -> Any:
         """Skip validation if the value is `None` when initialisation is delayed."""
@@ -205,54 +200,16 @@ def _skip_none_validation(cls, value: Any, handler: Callable) -> Any:
         return handler(value)
 
     def __post_init__(self, is_encoder_decoder: bool) -> None:
-        if self.max_model_len is None:
-            self.max_model_len = 8192
-
-        if self.max_num_seqs is None:
-            self.max_num_seqs = 128
-
         if is_encoder_decoder:
             # Chunked prefill should be disabled for encoder-decoder models.
             self.disable_chunked_mm_input = True
-            self.chunked_prefill_enabled = False
             self.enable_chunked_prefill = False
             self.long_prefill_token_threshold = 0
             logger.info(
                 "Encoder-decoder models do not support chunked prefill nor"
                 " prefix caching; disabling both."
             )
 
-        if self.max_num_batched_tokens is None:
-            if self.enable_chunked_prefill:
-                self.max_num_batched_tokens = DEFAULT_MAX_NUM_BATCHED_TOKENS
-            else:
-                # If max_model_len is too short, use
-                # DEFAULT_MAX_NUM_BATCHED_TOKENS as the default value
-                # for higher throughput.
-                self.max_num_batched_tokens = max(
-                    self.max_model_len, DEFAULT_MAX_NUM_BATCHED_TOKENS
-                )
-
-            if self.runner_type == "pooling":
-                # Choose specific value for higher throughput
-                self.max_num_batched_tokens = max(
-                    self.max_num_batched_tokens,
-                    POOLING_MODEL_MAX_NUM_BATCHED_TOKENS,
-                )
-            if self.is_multimodal_model:
-                # The value needs to be at least the number of multimodal tokens
-                self.max_num_batched_tokens = max(
-                    self.max_num_batched_tokens,
-                    MULTIMODAL_MODEL_MAX_NUM_BATCHED_TOKENS,
-                )
-
-            # When using default settings,
-            # Ensure max_num_batched_tokens does not exceed model limit.
-            # Some models (e.g., Whisper) have embeddings tied to max length.
-            self.max_num_batched_tokens = min(
-                self.max_num_seqs * self.max_model_len, self.max_num_batched_tokens
-            )
-
         self.max_num_encoder_input_tokens = self.max_num_batched_tokens
         self.encoder_cache_size = self.max_num_batched_tokens
 
@@ -262,7 +219,6 @@ def __post_init__(self, is_encoder_decoder: bool) -> None:
                 self.max_num_batched_tokens,
             )
 
-        self.chunked_prefill_enabled = self.enable_chunked_prefill
         if self.max_num_partial_prefills > 1:
             if self.long_prefill_token_threshold == 0:
                 self.long_prefill_token_threshold = int(self.max_model_len * 0.04)
@@ -276,6 +232,14 @@ def __post_init__(self, is_encoder_decoder: bool) -> None:
                 self.long_prefill_token_threshold,
             )
 
+    @property
+    def chunked_prefill_enabled(self) -> bool:
+        return self.enable_chunked_prefill
+
+    @chunked_prefill_enabled.setter
+    def chunked_prefill_enabled(self, value: bool):
+        self.enable_chunked_prefill = value
+
     @model_validator(mode="after")
     def _verify_args(self) -> Self:
         if (