[Misc] Refactor additional_config (#1029)

More and more config options are added to additional_config. This PR
provide a new AscendConfig to manage these config options by an easier
way to make code cleaner and readable.

 This PR also added the `additional_config` doc for users.

Added the test_ascend_config.py to make sure the new AscendConfig works
as expect.

TODO: Add e2e test with torchair and deepseek once the CI resource is
available.

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

tests/long_term/spec_decode/e2e/conftest.py

@@ -167,17 +167,17 @@ def run_equality_correctness_test(
 
     # TODO current torchair graph mode needs clean torchair cache.
     # if do not clean, it will raise error
-    additional_config = common_llm_kwargs.get("additional_config")
-    enable_graph_mode = additional_config.get(
-        "enable_graph_mode") if additional_config else False
+    torchair_graph_enabled = common_llm_kwargs.get(
+        "additional_config", {}).get("torchair_graph_config",
+                                     {}).get("enabled", False)
 
     with vllm_runner(**org_args) as vllm_model:
-        if enable_graph_mode:
+        if torchair_graph_enabled:
             _clean_torchair_cache()
         org_outputs = vllm_model.generate_w_logprobs(prompts, sampling_params)
 
     with vllm_runner(**sd_args) as vllm_model:
-        if enable_graph_mode:
+        if torchair_graph_enabled:
             _clean_torchair_cache()
         if ensure_all_accepted or expected_acceptance_rate is not None:
             # Force log interval to be 0 to catch all metrics.

tests/long_term/spec_decode/e2e/test_mtp_correctness.py

@@ -218,7 +218,9 @@ def test_mtp_e2e_greedy_logprobs(vllm_runner, common_llm_kwargs,
     "common_llm_kwargs",
     [{
         "additional_config": {
-            'enable_graph_mode': True,
+            'torchair_graph_config': {
+                "enabled": True,
+            },
         },
 
         # Print spec metrics.
@@ -262,7 +264,9 @@ def test_mtp_e2e_greedy_correctness_torchair_graph(
     "common_llm_kwargs",
     [{
         "additional_config": {
-            'enable_graph_mode': True,
+            'torchair_graph_config': {
+                "enabled": True,
+            },
         },
 
         # Print spec metrics.