[Feat] Remove reference cycle in error handling for faster GC

python/tvm_ffi/error.py

@@ -121,19 +121,25 @@ def append_traceback(
             The new traceback with the appended frame.
 
         """
-        frame = self._create_frame(filename, lineno, func)
-        return types.TracebackType(tb, frame, frame.f_lasti, lineno)
+        # Magic hack to prevent a circular reference
+        def create(tb: types.TracebackType | None, frame: types.FrameType, lineno: int) -> types.TracebackType:
+            return types.TracebackType(tb, frame, frame.f_lasti, lineno)
+        return create(tb, self._create_frame(filename, lineno, func), lineno)
 
 
 _TRACEBACK_MANAGER = TracebackManager()
 
 
 def _with_append_backtrace(py_error: BaseException, backtrace: str) -> BaseException:
     """Append the backtrace to the py_error and return it."""
-    tb = py_error.__traceback__
-    for filename, lineno, func in _parse_backtrace(backtrace):
-        tb = _TRACEBACK_MANAGER.append_traceback(tb, filename, lineno, func)
-    return py_error.with_traceback(tb)
+    # we manually delete py_error and tb to avoid reference cycle, making it faster to gc the locals inside the frame
+    try:
+        tb = py_error.__traceback__
+        for filename, lineno, func in _parse_backtrace(backtrace):
+            tb = _TRACEBACK_MANAGER.append_traceback(tb, filename, lineno, func)
+        return py_error.with_traceback(tb)
+    finally:
+        del py_error, tb
 
 
 def _traceback_to_backtrace_str(tb: types.TracebackType | None) -> str: