name : plugin_systemd.py from . import base from .decorators import * import tuned.logs from . import exceptions from tuned.utils.commands import commands import tuned.consts as consts import os import re log = tuned.logs.get() class SystemdPlugin(base.Plugin): """ `systemd`:: Plug-in for tuning systemd options. + The [option]`cpu_affinity` option allows setting CPUAffinity in `/etc/systemd/system.conf`. This configures the CPU affinity for the service manager as well as the default CPU affinity for all forked off processes. The option takes a comma-separated list of CPUs with optional CPU ranges specified by the minus sign (`-`). + .Set the CPUAffinity for `systemd` to `0 1 2 3` ==== ---- [systemd] cpu_affinity=0-3 ---- ==== + NOTE: These tunings are unloaded only on profile change followed by a reboot. """ def __init__(self, *args, **kwargs): if not os.path.isfile(consts.SYSTEMD_SYSTEM_CONF_FILE): raise exceptions.NotSupportedPluginException("Required systemd '%s' configuration file not found, disabling plugin." % consts.SYSTEMD_SYSTEM_CONF_FILE) super(SystemdPlugin, self).__init__(*args, **kwargs) self._cmd = commands() def _instance_init(self, instance): instance._has_dynamic_tuning = False instance._has_static_tuning = True def _instance_cleanup(self, instance): pass @classmethod def _get_config_options(cls): return { "cpu_affinity": None, } def _get_keyval(self, conf, key): if conf is not None: mo = re.search(r"^\s*" + key + r"\s*=\s*(.*)$", conf, flags = re.MULTILINE) if mo is not None and mo.lastindex == 1: return mo.group(1) return None # add/replace key with the value def _add_keyval(self, conf, key, val): (conf_new, nsubs) = re.subn(r"^(\s*" + key + r"\s*=).*$", r"\g<1>" + str(val), conf, flags = re.MULTILINE) if nsubs < 1: try: if conf[-1] != "\n": conf += "\n" except IndexError: pass conf += key + "=" + str(val) + "\n" return conf return conf_new def _del_key(self, conf, key): return re.sub(r"^\s*" + key + r"\s*=.*\n", "", conf, flags = re.MULTILINE) def _read_systemd_system_conf(self): systemd_system_conf = self._cmd.read_file(consts.SYSTEMD_SYSTEM_CONF_FILE, err_ret = None) if systemd_system_conf is None: log.error("error reading systemd configuration file") return None return systemd_system_conf def _write_systemd_system_conf(self, conf): tmpfile = consts.SYSTEMD_SYSTEM_CONF_FILE + consts.TMP_FILE_SUFFIX if not self._cmd.write_to_file(tmpfile, conf): log.error("error writing systemd configuration file") self._cmd.unlink(tmpfile, no_error = True) return False # Atomic replace, this doesn't work on Windows (AFAIK there is no way on Windows how to do this # atomically), but it's unlikely this code will run there if not self._cmd.rename(tmpfile, consts.SYSTEMD_SYSTEM_CONF_FILE): log.error("error replacing systemd configuration file '%s'" % consts.SYSTEMD_SYSTEM_CONF_FILE) self._cmd.unlink(tmpfile, no_error = True) return False return True def _get_storage_filename(self): return os.path.join(consts.PERSISTENT_STORAGE_DIR, self.name) def _remove_systemd_tuning(self): conf = self._read_systemd_system_conf() if (conf is not None): fname = self._get_storage_filename() cpu_affinity_saved = self._cmd.read_file(fname, err_ret = None, no_error = True) self._cmd.unlink(fname) if cpu_affinity_saved is None: conf = self._del_key(conf, consts.SYSTEMD_CPUAFFINITY_VAR) else: conf = self._add_keyval(conf, consts.SYSTEMD_CPUAFFINITY_VAR, cpu_affinity_saved) self._write_systemd_system_conf(conf) def _instance_unapply_static(self, instance, rollback = consts.ROLLBACK_SOFT): if rollback == consts.ROLLBACK_FULL: log.info("removing '%s' systemd tuning previously added by TuneD" % consts.SYSTEMD_CPUAFFINITY_VAR) self._remove_systemd_tuning() log.console("you may need to manualy run 'dracut -f' to update the systemd configuration in initrd image") # convert cpulist from systemd syntax to TuneD syntax and unpack it def _cpulist_convert_unpack(self, cpulist): if cpulist is None: return "" return " ".join(str(v) for v in self._cmd.cpulist_unpack(re.sub(r"\s+", r",", re.sub(r",\s+", r",", cpulist)))) @command_custom("cpu_affinity", per_device = False) def _cmdline(self, enabling, value, verify, ignore_missing): conf_affinity = None conf_affinity_unpacked = None v = self._cmd.unescape(self._variables.expand(self._cmd.unquote(value))) v_unpacked = " ".join(str(v) for v in self._cmd.cpulist_unpack(v)) conf = self._read_systemd_system_conf() if conf is not None: conf_affinity = self._get_keyval(conf, consts.SYSTEMD_CPUAFFINITY_VAR) conf_affinity_unpacked = self._cpulist_convert_unpack(conf_affinity) if verify: return self._verify_value("cpu_affinity", v_unpacked, conf_affinity_unpacked, ignore_missing) if enabling: fname = self._get_storage_filename() cpu_affinity_saved = self._cmd.read_file(fname, err_ret = None, no_error = True) if conf_affinity is not None and cpu_affinity_saved is None and v_unpacked != conf_affinity_unpacked: self._cmd.write_to_file(fname, conf_affinity, makedir = True) log.info("setting '%s' to '%s' in the '%s'" % (consts.SYSTEMD_CPUAFFINITY_VAR, v_unpacked, consts.SYSTEMD_SYSTEM_CONF_FILE)) self._write_systemd_system_conf(self._add_keyval(conf, consts.SYSTEMD_CPUAFFINITY_VAR, v_unpacked))