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node-feature-discovery/source/cpu/pstate.go
Bob Fournier a65f73e834 Support for additional cpu features
This adds additional cpu features:
- pstate status from status of intel_pstate driver
- pstate scaling settings from scaling_governor
- cstate enable from max_cstates in intel_idle driver
2021-03-05 13:15:49 -05:00

107 lines
3.2 KiB
Go

/*
Copyright 2017 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package cpu
import (
"fmt"
"io/ioutil"
"runtime"
"strings"
"k8s.io/klog/v2"
"sigs.k8s.io/node-feature-discovery/source"
)
// Discover p-state related features such as turbo boost.
func detectPstate() (map[string]string, error) {
// On other platforms, the frequency boost mechanism is software-based.
// So skip pstate detection on other architectures.
if runtime.GOARCH != "amd64" && runtime.GOARCH != "386" {
return nil, nil
}
// Get global pstate status
data, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/cpu/intel_pstate/status"))
if err != nil {
return nil, fmt.Errorf("could not read pstate status: %s", err.Error())
}
status := strings.TrimSpace(string(data))
if status == "off" {
// No need to check other pstate features
klog.Infof("intel_pstate driver is not in use")
return nil, nil
}
features := map[string]string{"status": status}
// Check turbo boost
bytes, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/cpu/intel_pstate/no_turbo"))
if err != nil {
klog.Errorf("can't detect whether turbo boost is enabled: %s", err.Error())
} else {
features["turbo"] = "false"
if bytes[0] == byte('0') {
features["turbo"] = "true"
}
}
if status != "active" {
// Don't check other features which depend on active state
return features, nil
}
// Determine scaling governor that is being used
policies, err := ioutil.ReadDir(source.SysfsDir.Path("devices/system/cpu/cpufreq"))
if err != nil {
klog.Errorf("failed to read cpufreq directory: %s", err.Error())
return features, nil
}
scaling := ""
for _, policy := range policies {
// Ensure at least one cpu is using this policy
cpus, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/cpu/cpufreq", policy.Name(), "affected_cpus"))
if err != nil {
klog.Errorf("could not read cpufreq policy %s affected_cpus", policy.Name())
continue
}
if strings.TrimSpace(string(cpus)) == "" {
klog.Infof("policy %s has no associated cpus", policy.Name())
continue
}
data, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/cpu/cpufreq", policy.Name(), "scaling_governor"))
if err != nil {
klog.Errorf("could not read cpufreq policy %s scaling_governor", policy.Name())
continue
}
policy_scaling := strings.TrimSpace(string(data))
// Check that all of the policies have the same scaling governor, if not don't set feature
if scaling != "" && scaling != policy_scaling {
klog.Infof("scaling_governor for policy %s doesn't match prior policy", policy.Name())
scaling = ""
break
}
scaling = policy_scaling
}
if scaling != "" {
features["scaling_governor"] = scaling
}
return features, nil
}