Auto handle PD disaggregation in bench_serving (#6587)

Co-authored-by: yizhang2077 <1109276519@qq.com>

docs/references/performance_analysis_and_optimization.rst

@@ -4,4 +4,4 @@ Performance Analysis & Optimization
    :maxdepth: 1
 
    benchmark_and_profiling.md
-   accuracy_evaluation.md
\ No newline at end of file
+   accuracy_evaluation.md

python/sglang/bench_serving.py

@@ -1304,14 +1304,12 @@ async def benchmark(
     if "sglang" in backend:
         server_info = requests.get(base_url + "/get_server_info")
         if server_info.status_code == 200:
-            if pd_separated:
-                accept_length = server_info.json()["decode"][0]["internal_states"][
-                    0
-                ].get("avg_spec_accept_length", None)
-            else:
-                accept_length = server_info.json()["internal_states"][0].get(
-                    "avg_spec_accept_length", None
-                )
+            server_info_json = server_info.json()
+            if "decode" in server_info_json:
+                server_info_json = server_info_json["decode"][0]
+            accept_length = server_info_json["internal_states"][0].get(
+                "avg_spec_accept_length", None
+            )
         else:
             accept_length = None
     else:

scripts/playground/disaggregation/cli-logprob.py

-prompt = "The capital of taiwan is "
+prompt = "The capital of france is "
 
 import json