refactor: switch mp-method to forkserver globally

Author: xmatthias

freqtrade/main.py

@@ -18,7 +18,12 @@
 from freqtrade.constants import DOCS_LINK
 from freqtrade.exceptions import ConfigurationError, FreqtradeException, OperationalException
 from freqtrade.loggers import setup_logging_pre
-from freqtrade.system import asyncio_setup, gc_set_threshold, print_version_info
+from freqtrade.system import (
+    asyncio_setup,
+    gc_set_threshold,
+    print_version_info,
+    set_mp_start_method,
+)
 
 
 logger = logging.getLogger("freqtrade")
@@ -44,6 +49,7 @@ def main(sysargv: list[str] | None = None) -> None:
         elif "func" in args:
             logger.info(f"freqtrade {__version__}")
             gc_set_threshold()
+            set_mp_start_method()
             return_code = args["func"](args)
         else:
             # No subcommand was issued.

freqtrade/optimize/hyperopt/hyperopt_optimizer.py

@@ -7,7 +7,7 @@
 import sys
 import warnings
 from datetime import UTC, datetime
-from multiprocessing import Manager, get_all_start_methods, set_start_method
+from multiprocessing import Manager
 from pathlib import Path
 from typing import Any
 
@@ -125,12 +125,6 @@ def _setup_logging_mp_workaround(self) -> None:
         local_queue must be a global and passed to the child process via inheritance.
         """
         global log_queue
-        try:
-            sms = get_all_start_methods()
-            if "forkserver" in sms:
-                set_start_method("forkserver")
-        except RuntimeError:
-            pass  # start method has already been set
         m = Manager()
         log_queue = m.Queue()
         logger.info(f"manager queue {type(log_queue)}")

freqtrade/system/__init__.py

@@ -2,7 +2,8 @@
 
 from freqtrade.system.asyncio_config import asyncio_setup
 from freqtrade.system.gc_setup import gc_set_threshold
+from freqtrade.system.set_mp_start_method import set_mp_start_method
 from freqtrade.system.version_info import print_version_info
 
 
-__all__ = ["asyncio_setup", "gc_set_threshold", "print_version_info"]
+__all__ = ["asyncio_setup", "gc_set_threshold", "print_version_info", "set_mp_start_method"]

freqtrade/system/set_mp_start_method.py

@@ -0,0 +1,14 @@
+from multiprocessing import get_all_start_methods, get_start_method, set_start_method
+
+
+def set_mp_start_method():
+    """
+    Set multiprocessing start method to not be fork.
+    forkserver will become the default in 3.14 - and is deprecated in 3.13
+    """
+    try:
+        sms = get_all_start_methods()
+        if "forkserver" in sms and get_start_method(True) is None:
+            set_start_method("forkserver")
+    except RuntimeError:
+        pass