some modifications to ensure 50K context input

qwen3_6_scripts/patch_xformers_sdpa_seq.py

@@ -24,6 +24,12 @@ flash attention kernel（ixformer / cudnnFlashAttnForward）。
   max-model-len=8192  → 峰值 ~800 MB
   max-model-len=16384 → 峰值 ~3.2 GB
 
+额外 patch（arg_utils.py）：
+  vllm 0.6.3 在 max_model_len > 32K 时会自动开启 chunked prefill（无命令行
+  关闭选项），原意是防止 profiling OOM。但 _run_sdpa_fallback 已通过 Q-tiling
+  解决了该问题，chunked prefill 反而会把推理路径从 _run_sdpa_fallback 切换到
+  _forward_prefix_pytorch，属于不必要的行为变更，因此一并禁用该自动逻辑。
+
 Deploy:
   python3 modified_scripts/patch_xformers_sdpa_seq.py
 """
@@ -33,6 +39,33 @@ XFORMERS_PATH = (
     "vllm/attention/backends/xformers.py"
 )
 
+ARG_UTILS_PATH = (
+    "/usr/local/corex/lib64/python3/dist-packages/"
+    "vllm/engine/arg_utils.py"
+)
+
+# vllm 0.6.3 自动开启 chunked prefill 的原始块
+_ARG_OLD_BLOCK = """\
+                if (is_gpu and not use_sliding_window and not use_spec_decode
+                        and not self.enable_lora
+                        and not self.enable_prompt_adapter):
+                    self.enable_chunked_prefill = True
+                    logger.warning(
+                        "Chunked prefill is enabled by default for models with "
+                        "max_model_len > 32K. Currently, chunked prefill might "
+                        "not work with some features or models. If you "
+                        "encounter any issues, please disable chunked prefill "
+                        "by setting --enable-chunked-prefill=False.")\
+"""
+
+_ARG_NEW_BLOCK = """\
+                if (is_gpu and not use_sliding_window and not use_spec_decode
+                        and not self.enable_lora
+                        and not self.enable_prompt_adapter):
+                    pass  # skip auto-enable: Q-tiling in _run_sdpa_fallback
+                          # handles long-context memory without chunked prefill\
+"""
+
 FALLBACK_METHOD = '''
     def _run_sdpa_fallback(
         self,
@@ -203,10 +236,35 @@ def patch_file(path):
         print(f"  Written: {path}")
 
 
+def patch_arg_utils(path):
+    with open(path, "r") as f:
+        content = f.read()
+    changed = False
+
+    if "skip auto-enable: Q-tiling" in content:
+        print("  [skip] chunked-prefill auto-enable already disabled")
+    elif _ARG_OLD_BLOCK in content:
+        content = content.replace(_ARG_OLD_BLOCK, _ARG_NEW_BLOCK, 1)
+        print("  [ok]   disabled chunked-prefill auto-enable for 32K+")
+        changed = True
+    else:
+        print("  [warn] target block not found — check arg_utils.py version")
+
+    if changed:
+        with open(path, "w") as f:
+            f.write(content)
+        print(f"  Written: {path}")
+
+
 def main():
     print("=== patch_xformers_sdpa_seq (sequential, pure-math) ===")
     print(f"Target: {XFORMERS_PATH}")
     patch_file(XFORMERS_PATH)
+
+    print("\n=== patch_arg_utils (disable chunked-prefill auto-enable) ===")
+    print(f"Target: {ARG_UTILS_PATH}")
+    patch_arg_utils(ARG_UTILS_PATH)
+
     print("\nDone.")