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node-feature-discovery/source/cpu/cstate.go
Markus Lehtonen 43e0f83940 source/cpu: better error reporting
Drop confusing errors in the log when intel pstate or cstate driver is
not enabled in the system. However, we still log an error if sysfs is
not available at all, in which case we're not able to detect these
correctly.
2021-08-13 09:16:03 +03:00

67 lines
2 KiB
Go

/*
Copyright 2021 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"
"os"
"path/filepath"
"strconv"
"strings"
"k8s.io/klog/v2"
"sigs.k8s.io/node-feature-discovery/source"
)
// Discover if c-states are enabled
func detectCstate() (bool, bool, error) {
// Check that sysfs is available
sysfsBase := source.SysfsDir.Path("devices/system/cpu")
if _, err := os.Stat(sysfsBase); err != nil {
return false, false, fmt.Errorf("unable to detect cstate status: %w", err)
}
cpuidleDir := filepath.Join(sysfsBase, "cpuidle")
if _, err := os.Stat(cpuidleDir); os.IsNotExist(err) {
klog.V(1).Info("cpuidle disabled in the kernel")
return false, false, nil
}
// When the intel_idle driver is in use (default), check setting of max_cstates
driver, err := ioutil.ReadFile(filepath.Join(cpuidleDir, "current_driver"))
if err != nil {
return false, false, fmt.Errorf("cannot get driver for cpuidle: %w", err)
}
if d := strings.TrimSpace(string(driver)); d != "intel_idle" {
// Currently only checking intel_idle driver for cstates
klog.V(1).Infof("intel_idle driver is not in use (%s is active)", d)
return false, false, nil
}
data, err := ioutil.ReadFile(source.SysfsDir.Path("module/intel_idle/parameters/max_cstate"))
if err != nil {
return false, false, fmt.Errorf("cannot determine cstate from max_cstates: %w", err)
}
cstates, err := strconv.Atoi(strings.TrimSpace(string(data)))
if err != nil {
return false, false, fmt.Errorf("non-integer value of cstates: %w", err)
}
return cstates > 0, true, nil
}