controlsd: avoid lag on first iteration due to get_short_branch (#25031)

* controlsd: avoid lag on first iteration due to get_short_branch

* always cache

selfdrive/controls/controlsd.py

@@ -12,6 +12,7 @@ import cereal.messaging as messaging
 from common.conversions import Conversions as CV
 from panda import ALTERNATIVE_EXPERIENCE
 from system.swaglog import cloudlog
+from system.version import get_short_branch
 from selfdrive.boardd.boardd import can_list_to_can_capnp
 from selfdrive.car.car_helpers import get_car, get_startup_event, get_one_can
 from selfdrive.controls.lib.lane_planner import CAMERA_OFFSET
@@ -62,6 +63,9 @@ class Controls:
   def __init__(self, sm=None, pm=None, can_sock=None, CI=None):
     config_realtime_process(4, Priority.CTRL_HIGH)
 
+    # Ensure the current branch is cached, otherwise the first iteration of controlsd lags
+    self.branch = get_short_branch("")
+
     # Setup sockets
     self.pm = pm
     if self.pm is None:

selfdrive/controls/lib/events.py

@@ -222,7 +222,7 @@ def user_soft_disable_alert(alert_text_2: str) -> AlertCallbackType:
   return func
 
 def startup_master_alert(CP: car.CarParams, CS: car.CarState, sm: messaging.SubMaster, metric: bool, soft_disable_time: int) -> Alert:
-  branch = get_short_branch("")
+  branch = get_short_branch("")  # Ensure get_short_branch is cached to avoid lags on startup
   if "REPLAY" in os.environ:
     branch = "replay"