Enable prefetching before runpy (#16427)

This PR enables prefetching before we execute the `runpy` module and
script code.

python/cudf/cudf/pandas/__main__.py

@@ -73,6 +73,16 @@ def main():
     args = parser.parse_args()
 
     rmm_mode = install()
+    if "managed" in rmm_mode:
+        for key in {
+            "column_view::get_data",
+            "mutable_column_view::get_data",
+            "gather",
+            "hash_join",
+        }:
+            from cudf._lib import pylibcudf
+
+            pylibcudf.experimental.enable_prefetching(key)
     with profile(args.profile, args.line_profile, args.args[0]) as fn:
         args.args[0] = fn
         if args.module:
@@ -86,17 +96,6 @@ def main():
             sys.argv[:] = args.args
             runpy.run_path(args.args[0], run_name="__main__")
 
-    if "managed" in rmm_mode:
-        for key in {
-            "column_view::get_data",
-            "mutable_column_view::get_data",
-            "gather",
-            "hash_join",
-        }:
-            from cudf._lib import pylibcudf
-
-            pylibcudf.experimental.enable_prefetching(key)
-
 
 if __name__ == "__main__":
     main()