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4dcb4974e5
Sometimes it could be required to change the governor for a set of different CPUs. This patch provides an utility method to easily and achieve that with a single method call. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
352 lines
15 KiB
Python
352 lines
15 KiB
Python
# Copyright 2014-2015 ARM Limited
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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from devlib.module import Module
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from devlib.exception import TargetError
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from devlib.utils.misc import memoized
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# a dict of governor name and a list of it tunables that can't be read
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WRITE_ONLY_TUNABLES = {
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'interactive': ['boostpulse']
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}
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class CpufreqModule(Module):
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name = 'cpufreq'
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@staticmethod
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def probe(target):
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# x86 with Intel P-State driver
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if target.abi == 'x86_64':
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path = '/sys/devices/system/cpu/intel_pstate'
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if target.file_exists(path):
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return True
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# Generic CPUFreq support (single policy)
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path = '/sys/devices/system/cpu/cpufreq'
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if target.file_exists(path):
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return True
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# Generic CPUFreq support (per CPU policy)
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path = '/sys/devices/system/cpu/cpu0/cpufreq'
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return target.file_exists(path)
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def __init__(self, target):
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super(CpufreqModule, self).__init__(target)
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self._governor_tunables = {}
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@memoized
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def list_governors(self, cpu):
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"""Returns a list of governors supported by the cpu."""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_available_governors'.format(cpu)
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output = self.target.read_value(sysfile)
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return output.strip().split()
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def get_governor(self, cpu):
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"""Returns the governor currently set for the specified CPU."""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_governor'.format(cpu)
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return self.target.read_value(sysfile)
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def set_governor(self, cpu, governor, **kwargs):
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"""
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Set the governor for the specified CPU.
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See https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
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:param cpu: The CPU for which the governor is to be set. This must be
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the full name as it appears in sysfs, e.g. "cpu0".
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:param governor: The name of the governor to be used. This must be
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supported by the specific device.
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Additional keyword arguments can be used to specify governor tunables for
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governors that support them.
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:note: On big.LITTLE all cores in a cluster must be using the same governor.
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Setting the governor on any core in a cluster will also set it on all
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other cores in that cluster.
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:raises: TargetError if governor is not supported by the CPU, or if,
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for some reason, the governor could not be set.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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supported = self.list_governors(cpu)
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if governor not in supported:
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raise TargetError('Governor {} not supported for cpu {}'.format(governor, cpu))
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_governor'.format(cpu)
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self.target.write_value(sysfile, governor)
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self.set_governor_tunables(cpu, governor, **kwargs)
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def list_governor_tunables(self, cpu):
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"""Returns a list of tunables available for the governor on the specified CPU."""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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governor = self.get_governor(cpu)
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if governor not in self._governor_tunables:
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try:
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tunables_path = '/sys/devices/system/cpu/{}/cpufreq/{}'.format(cpu, governor)
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self._governor_tunables[governor] = self.target.list_directory(tunables_path)
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except TargetError: # probably an older kernel
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try:
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tunables_path = '/sys/devices/system/cpu/cpufreq/{}'.format(governor)
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self._governor_tunables[governor] = self.target.list_directory(tunables_path)
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except TargetError: # governor does not support tunables
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self._governor_tunables[governor] = []
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return self._governor_tunables[governor]
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def get_governor_tunables(self, cpu):
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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governor = self.get_governor(cpu)
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tunables = {}
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for tunable in self.list_governor_tunables(cpu):
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if tunable not in WRITE_ONLY_TUNABLES.get(governor, []):
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try:
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path = '/sys/devices/system/cpu/{}/cpufreq/{}/{}'.format(cpu, governor, tunable)
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tunables[tunable] = self.target.read_value(path)
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except TargetError: # May be an older kernel
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path = '/sys/devices/system/cpu/cpufreq/{}/{}'.format(governor, tunable)
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tunables[tunable] = self.target.read_value(path)
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return tunables
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def set_governor_tunables(self, cpu, governor=None, **kwargs):
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"""
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Set tunables for the specified governor. Tunables should be specified as
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keyword arguments. Which tunables and values are valid depends on the
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governor.
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:param cpu: The cpu for which the governor will be set. This must be the
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full cpu name as it appears in sysfs, e.g. ``cpu0``.
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:param governor: The name of the governor. Must be all lower case.
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The rest should be keyword parameters mapping tunable name onto the value to
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be set for it.
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:raises: TargetError if governor specified is not a valid governor name, or if
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a tunable specified is not valid for the governor, or if could not set
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tunable.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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if governor is None:
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governor = self.get_governor(cpu)
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valid_tunables = self.list_governor_tunables(cpu)
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for tunable, value in kwargs.iteritems():
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if tunable in valid_tunables:
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try:
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path = '/sys/devices/system/cpu/{}/cpufreq/{}/{}'.format(cpu, governor, tunable)
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self.target.write_value(path, value)
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except TargetError: # May be an older kernel
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path = '/sys/devices/system/cpu/cpufreq/{}/{}'.format(governor, tunable)
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self.target.write_value(path, value)
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else:
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message = 'Unexpected tunable {} for governor {} on {}.\n'.format(tunable, governor, cpu)
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message += 'Available tunables are: {}'.format(valid_tunables)
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raise TargetError(message)
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@memoized
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def list_frequencies(self, cpu):
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"""Returns a list of frequencies supported by the cpu or an empty list
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if not could be found."""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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try:
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cmd = 'cat /sys/devices/system/cpu/{}/cpufreq/scaling_available_frequencies'.format(cpu)
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output = self.target.execute(cmd)
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available_frequencies = map(int, output.strip().split()) # pylint: disable=E1103
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except TargetError:
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# On some devices scaling_frequencies is not generated.
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# http://adrynalyne-teachtofish.blogspot.co.uk/2011/11/how-to-enable-scalingavailablefrequenci.html
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# Fall back to parsing stats/time_in_state
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cmd = 'cat /sys/devices/system/cpu/{}/cpufreq/stats/time_in_state'.format(cpu)
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out_iter = iter(self.target.execute(cmd).strip().split())
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available_frequencies = map(int, reversed([f for f, _ in zip(out_iter, out_iter)]))
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return available_frequencies
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def get_min_frequency(self, cpu):
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"""
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Returns the min frequency currently set for the specified CPU.
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Warning, this method does not check if the cpu is online or not. It will
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try to read the minimum frequency and the following exception will be
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raised ::
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:raises: TargetError if for some reason the frequency could not be read.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_min_freq'.format(cpu)
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return self.target.read_int(sysfile)
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def set_min_frequency(self, cpu, frequency, exact=True):
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"""
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Set's the minimum value for CPU frequency. Actual frequency will
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depend on the Governor used and may vary during execution. The value should be
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either an int or a string representing an integer. The Value must also be
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supported by the device. The available frequencies can be obtained by calling
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get_frequencies() or examining
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/sys/devices/system/cpu/cpuX/cpufreq/scaling_frequencies
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on the device.
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:raises: TargetError if the frequency is not supported by the CPU, or if, for
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some reason, frequency could not be set.
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:raises: ValueError if ``frequency`` is not an integer.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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available_frequencies = self.list_frequencies(cpu)
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try:
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value = int(frequency)
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if exact and available_frequencies and value not in available_frequencies:
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raise TargetError('Can\'t set {} frequency to {}\nmust be in {}'.format(cpu,
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value,
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available_frequencies))
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_min_freq'.format(cpu)
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self.target.write_value(sysfile, value)
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except ValueError:
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raise ValueError('Frequency must be an integer; got: "{}"'.format(frequency))
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def get_frequency(self, cpu):
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"""
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Returns the current frequency currently set for the specified CPU.
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Warning, this method does not check if the cpu is online or not. It will
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try to read the current frequency and the following exception will be
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raised ::
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:raises: TargetError if for some reason the frequency could not be read.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_cur_freq'.format(cpu)
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return self.target.read_int(sysfile)
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def set_frequency(self, cpu, frequency, exact=True):
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"""
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Set's the minimum value for CPU frequency. Actual frequency will
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depend on the Governor used and may vary during execution. The value should be
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either an int or a string representing an integer.
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If ``exact`` flag is set (the default), the Value must also be supported by
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the device. The available frequencies can be obtained by calling
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get_frequencies() or examining
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/sys/devices/system/cpu/cpuX/cpufreq/scaling_frequencies
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on the device (if it exists).
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:raises: TargetError if the frequency is not supported by the CPU, or if, for
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some reason, frequency could not be set.
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:raises: ValueError if ``frequency`` is not an integer.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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try:
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value = int(frequency)
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if exact:
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available_frequencies = self.list_frequencies(cpu)
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if available_frequencies and value not in available_frequencies:
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raise TargetError('Can\'t set {} frequency to {}\nmust be in {}'.format(cpu,
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value,
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available_frequencies))
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if self.get_governor(cpu) != 'userspace':
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raise TargetError('Can\'t set {} frequency; governor must be "userspace"'.format(cpu))
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_setspeed'.format(cpu)
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self.target.write_value(sysfile, value, verify=False)
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except ValueError:
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raise ValueError('Frequency must be an integer; got: "{}"'.format(frequency))
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def get_max_frequency(self, cpu):
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"""
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Returns the max frequency currently set for the specified CPU.
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Warning, this method does not check if the cpu is online or not. It will
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try to read the maximum frequency and the following exception will be
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raised ::
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:raises: TargetError if for some reason the frequency could not be read.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_max_freq'.format(cpu)
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return self.target.read_int(sysfile)
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def set_max_frequency(self, cpu, frequency, exact=True):
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"""
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Set's the minimum value for CPU frequency. Actual frequency will
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depend on the Governor used and may vary during execution. The value should be
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either an int or a string representing an integer. The Value must also be
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supported by the device. The available frequencies can be obtained by calling
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get_frequencies() or examining
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/sys/devices/system/cpu/cpuX/cpufreq/scaling_frequencies
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on the device.
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:raises: TargetError if the frequency is not supported by the CPU, or if, for
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some reason, frequency could not be set.
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:raises: ValueError if ``frequency`` is not an integer.
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"""
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if isinstance(cpu, int):
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cpu = 'cpu{}'.format(cpu)
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available_frequencies = self.list_frequencies(cpu)
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try:
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value = int(frequency)
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if exact and available_frequencies and value not in available_frequencies:
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raise TargetError('Can\'t set {} frequency to {}\nmust be in {}'.format(cpu,
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value,
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available_frequencies))
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sysfile = '/sys/devices/system/cpu/{}/cpufreq/scaling_max_freq'.format(cpu)
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self.target.write_value(sysfile, value)
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except ValueError:
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raise ValueError('Frequency must be an integer; got: "{}"'.format(frequency))
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def set_governor_for_cpus(self, cpus, governor, **kwargs):
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"""
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Set the governor for the specified list of CPUs.
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See https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
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:param cpus: The list of CPU for which the governor is to be set.
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"""
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online_cpus = self.target.list_online_cpus()
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for cpu in online_cpus:
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self.set_governor(cpu, governor, kwargs)
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def set_frequency_for_cpus(self, cpus, freq, exact=False):
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"""
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Set the frequency for the specified list of CPUs.
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See https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
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:param cpus: The list of CPU for which the frequency has to be set.
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"""
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online_cpus = self.target.list_online_cpus()
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for cpu in online_cpus:
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self.set_frequency(cpu, freq, exact)
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