[Scheduler] Add AscendScheduler. (#543)

This PR adds AscendScheduler to vllm v1 engine.
This scheduler currently supports v0-style prefill-first scheduling
strategy.
In the future more schedule methods will be supported by this scheduler.

---------

Signed-off-by: hw_whx <wanghexiang7@huawei.com>
Co-authored-by: hw_whx <wanghexiang7@huawei.com>

vllm_ascend/core/schedule_config.py

@@ -0,0 +1,73 @@
+#
+# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
+# This file is a part of the vllm-ascend project.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from dataclasses import dataclass, fields
+from typing import Type, Union
+
+from vllm.config import SchedulerConfig
+
+
+@dataclass
+class AscendSchedulerConfig(SchedulerConfig):
+    enable_chunked_prefill: bool = False
+    policy: str = "fcfs"
+    num_scheduler_steps: int = 1
+    scheduler_cls: Union[str, Type[object]] = (
+        "vllm_ascend.core.scheduler.AscendScheduler")
+
+    @classmethod
+    def initialize_from_config(
+        cls,
+        vllm_scheduler_config: SchedulerConfig,
+        ascend_scheduler_config: dict,
+    ):
+        scheduler_config = {
+            field.name: getattr(vllm_scheduler_config, field.name)
+            for field in fields(vllm_scheduler_config) if field.init
+        }
+        # Override default values into original SchedulerConfig
+        scheduler_config["enable_chunked_prefill"] = False
+        scheduler_config["policy"] = "fcfs"
+        scheduler_config["num_scheduler_steps"] = 1
+        scheduler_config["scheduler_cls"] = (
+            "vllm_ascend.core.scheduler.AscendScheduler")
+        # Override params in original SchedulerConfig with params in additional_config.ascend_scheduler_config
+        for k, v in ascend_scheduler_config.items():
+            scheduler_config[k] = v
+        return cls(**scheduler_config)
+
+    def __post_init__(self) -> None:
+        self.max_num_encoder_input_tokens = self.max_num_batched_tokens
+        self.encoder_cache_size = self.max_num_batched_tokens
+        self.chunked_prefill_enabled = self.enable_chunked_prefill
+        if self.policy != "fcfs":
+            raise NotImplementedError(
+                f"currently AscendScheduler only supports fcfs policy, got {self.policy}"
+            )
+        if self.is_multimodal_model:
+            raise NotImplementedError(
+                "currently AscendScheduler only supports LLM modles.")
+        if self.num_scheduler_steps > 1:
+            raise NotImplementedError(
+                "currently AscendScheduler doesn't support multi-step.")
+        if self.send_delta_data:
+            raise NotImplementedError(
+                "currently AscendScheduler doesn't support send_delta_data.")
+        if self.delay_factor > 0:
+            raise NotImplementedError(
+                "currently AscendScheduler doesn't support scheduler_delay_factor."
+            )