Only read cpu once during systemmonitor setup (#112863)

* Only read cpu once during systemmonitor setup

* type

homeassistant/components/systemmonitor/sensor.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from collections.abc import Callable
+import contextlib
 from dataclasses import dataclass
 from datetime import datetime
 from functools import lru_cache
@@ -71,13 +72,6 @@ def get_cpu_icon() -> Literal["mdi:cpu-64-bit", "mdi:cpu-32-bit"]:
     return "mdi:cpu-32-bit"
 
 
-def get_processor_temperature(
-    entity: SystemMonitorSensor,
-) -> float | None:
-    """Return processor temperature."""
-    return read_cpu_temperature(entity.hass, entity.coordinator.data.temperatures)
-
-
 def get_process(entity: SystemMonitorSensor) -> str:
     """Return process."""
     state = STATE_OFF
@@ -374,7 +368,9 @@ SENSOR_TYPES: dict[str, SysMonitorSensorEntityDescription] = {
         native_unit_of_measurement=UnitOfTemperature.CELSIUS,
         device_class=SensorDeviceClass.TEMPERATURE,
         state_class=SensorStateClass.MEASUREMENT,
-        value_fn=get_processor_temperature,
+        value_fn=lambda entity: read_cpu_temperature(
+            entity.coordinator.data.temperatures
+        ),
         none_is_unavailable=True,
         add_to_update=lambda entity: ("temperatures", ""),
     ),
@@ -506,22 +502,21 @@ async def async_setup_entry(  # noqa: C901
     legacy_resources: set[str] = set(entry.options.get("resources", []))
     loaded_resources: set[str] = set()
     coordinator: SystemMonitorCoordinator = hass.data[DOMAIN_COORDINATOR]
+    sensor_data = coordinator.data
 
     def get_arguments() -> dict[str, Any]:
         """Return startup information."""
-        disk_arguments = get_all_disk_mounts(hass)
-        network_arguments = get_all_network_interfaces(hass)
-        try:
-            cpu_temperature = read_cpu_temperature(hass)
-        except AttributeError:
-            cpu_temperature = 0.0
         return {
-            "disk_arguments": disk_arguments,
-            "network_arguments": network_arguments,
-            "cpu_temperature": cpu_temperature,
+            "disk_arguments": get_all_disk_mounts(hass),
+            "network_arguments": get_all_network_interfaces(hass),
         }
 
+    cpu_temperature: float | None = None
+    with contextlib.suppress(AttributeError):
+        cpu_temperature = read_cpu_temperature(sensor_data.temperatures)
+
     startup_arguments = await hass.async_add_executor_job(get_arguments)
+    startup_arguments["cpu_temperature"] = cpu_temperature
 
     _LOGGER.debug("Setup from options %s", entry.options)