[FRONTEND] Ensure version_key is called at most once (#519)

Co-authored-by: hauntsaninja <>

python/triton/code_gen.py

@@ -11,6 +11,7 @@ import subprocess
 import sys
 import tempfile
 import textwrap
+import threading
 import time
 import warnings
 from typing import Dict, Set, Tuple, Union
@@ -1058,8 +1059,20 @@ class Autotuner:
         return self.kernel(*args, num_warps=config.num_warps, num_stages=config.num_stages, **kwargs, **config.kwargs)
 
 
-@functools.lru_cache()
+_version_key_lock = threading.Lock()
+_version_key = None
+
+
 def version_key():
+    global _version_key
+
+    if _version_key is not None:
+        return _version_key
+
+    with _version_key_lock:
+        if _version_key is not None:
+            return _version_key
+
         import pkgutil
         contents = []
         # frontend
@@ -1078,7 +1091,8 @@ def version_key():
             ptxas_version = hashlib.md5(subprocess.check_output(["ptxas", "--version"])).hexdigest()
         except Exception:
             ptxas_version = ''
-    return '-'.join(triton.__version__) + '-' + ptxas_version + '-' + '-'.join(contents)
+        _version_key = '-'.join(triton.__version__) + '-' + ptxas_version + '-' + '-'.join(contents)
+        return _version_key
 
 
 class DependenciesFinder(ast.NodeVisitor):