Detect host support for CPU realtime + add an option for enable it (#2602)

supervisor/const.py

@@ -68,6 +68,7 @@ ENV_SUPERVISOR_DEV = "SUPERVISOR_DEV"
 ENV_SUPERVISOR_MACHINE = "SUPERVISOR_MACHINE"
 ENV_SUPERVISOR_NAME = "SUPERVISOR_NAME"
 ENV_SUPERVISOR_SHARE = "SUPERVISOR_SHARE"
+ENV_SUPERVISOR_CPU_RT = "SUPERVISOR_CPU_RT"
 
 REQUEST_FROM = "HASSIO_FROM"
 

supervisor/docker/__init__.py

@@ -2,6 +2,8 @@
 from contextlib import suppress
 from ipaddress import IPv4Address
 import logging
+import os
+from pathlib import Path
 from typing import Any, Dict, Optional
 
 import attr
@@ -13,6 +15,7 @@ from ..const import (
     ATTR_REGISTRIES,
     DNS_SUFFIX,
     DOCKER_NETWORK,
+    ENV_SUPERVISOR_CPU_RT,
     FILE_HASSIO_DOCKER,
     SOCKET_DOCKER,
 )
@@ -55,6 +58,13 @@ class DockerInfo:
         """Return true, if docker version is supported."""
         return self.version >= MIN_SUPPORTED_DOCKER
 
+    @property
+    def support_cpu_realtime(self) -> bool:
+        """Return true, if CONFIG_RT_GROUP_SCHED is loaded."""
+        if not Path("/sys/fs/cgroup/cpu.rt_runtime_us").exists():
+            return False
+        return bool(os.environ.get(ENV_SUPERVISOR_CPU_RT, 0))
+
 
 class DockerConfig(JsonConfig):
     """Home Assistant core object for Docker configuration."""

supervisor/docker/addon.py

@@ -276,6 +276,10 @@ class DockerAddon(DockerInterface):
     @property
     def cpu_rt_runtime(self) -> Optional[int]:
         """Limit CPU real-time runtime in microseconds."""
+        if not self.sys_docker.info.support_cpu_realtime:
+            return None
+
+        # If need CPU RT
         if self.addon.with_realtime:
             return 950000
         return None

supervisor/docker/audio.py

@@ -1,6 +1,6 @@
 """Audio docker object."""
 import logging
-from typing import Dict, List
+from typing import Dict, List, Optional
 
 import docker
 
@@ -61,6 +61,13 @@ class DockerAudio(DockerInterface, CoreSysAttributes):
         """Generate ulimits for audio."""
         return [docker.types.Ulimit(name="rtprio", soft=99)]
 
+    @property
+    def cpu_rt_runtime(self) -> Optional[int]:
+        """Limit CPU real-time runtime in microseconds."""
+        if not self.sys_docker.info.support_cpu_realtime:
+            return None
+        return 950000
+
     def _run(self) -> None:
         """Run Docker image.
 
@@ -83,7 +90,7 @@ class DockerAudio(DockerInterface, CoreSysAttributes):
             detach=True,
             cap_add=self.capabilities,
             ulimits=self.ulimits,
-            cpu_rt_runtime=950000,
+            cpu_rt_runtime=self.cpu_rt_runtime,
             device_cgroup_rules=self.cgroups_rules,
             environment={ENV_TIME: self.sys_config.timezone},
             volumes=self.volumes,