Fallback to lower triton version for unfound fused moe configs (sgl-project#7013)

Author: Fridge003

python/sglang/srt/layers/moe/fused_moe_triton/fused_moe.py

@@ -983,6 +983,8 @@ def get_moe_configs(
     kernel on a given batch size bs, the closest batch size in the grid should
     be picked and the associated configuration chosen to invoke the kernel.
     """
+    # Supported Triton versions, should be sorted from the newest to the oldest
+    supported_triton_versions = ["3.3.1", "3.2.0", "3.1.0"]
 
     # First look up if an optimized configuration is available in the configs
     # directory
@@ -1005,12 +1007,28 @@ def get_moe_configs(
             # For example, updating the Triton version might cause all old configs to become suboptimal.
             # To achieve the best performance, consider re-tuning the Triton fused MOE kernel in your environment.
             # For the tuning method, refer to: https://github.com/sgl-project/sglang/tree/main/benchmark/kernels/fused_moe_triton
-            log_info_on_rank0(
-                logger, f"Using MoE kernel config from {config_file_path}."
-            )
+            logger.info(f"Using MoE kernel config from {config_file_path}.")
             # If a configuration has been found, return it
             return {int(key): val for key, val in json.load(f).items()}
 
+    # Searching for other triton versions that supports the same config
+    for try_triton_version in supported_triton_versions:
+        if try_triton_version == triton_version:
+            continue
+        try_config_file_path = os.path.join(
+            os.path.dirname(os.path.realpath(__file__)),
+            "configs",
+            f"triton_{try_triton_version.replace('.', '_')}",
+            json_file_name,
+        )
+        if os.path.exists(try_config_file_path):
+            with open(try_config_file_path) as f:
+                logger.warning(
+                    f"Config file not found at {config_file_path}. Fallback to triton version {try_triton_version} and use MoE kernel config from {try_config_file_path}. Performance might be sub-optimal!",
+                )
+                # If a configuration has been found, return it
+                return {int(key): val for key, val in json.load(f).items()}
+
     # If no optimized configuration is available, we will use the default
     # configuration
     logger.warning(