mirror of
https://github.com/kubernetes-sigs/node-feature-discovery.git
synced 2024-12-14 11:57:51 +00:00
70 lines
2.1 KiB
Go
70 lines
2.1 KiB
Go
/*
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Copyright 2021 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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package cpu
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import (
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"fmt"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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"k8s.io/klog/v2"
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"sigs.k8s.io/node-feature-discovery/pkg/utils/hostpath"
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)
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// Discover if c-states are enabled
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func detectCstate() (map[string]string, error) {
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cstate := make(map[string]string)
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// Check that sysfs is available
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sysfsBase := hostpath.SysfsDir.Path("devices/system/cpu")
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if _, err := os.Stat(sysfsBase); err != nil {
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return cstate, fmt.Errorf("unable to detect cstate status: %w", err)
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}
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cpuidleDir := filepath.Join(sysfsBase, "cpuidle")
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if _, err := os.Stat(cpuidleDir); os.IsNotExist(err) {
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klog.V(1).InfoS("cpuidle disabled in the kernel")
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return cstate, nil
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}
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// When the intel_idle driver is in use (default), check setting of max_cstates
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driver, err := os.ReadFile(filepath.Join(cpuidleDir, "current_driver"))
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if err != nil {
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return cstate, fmt.Errorf("cannot get driver for cpuidle: %w", err)
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}
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if d := strings.TrimSpace(string(driver)); d != "intel_idle" {
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// Currently only checking intel_idle driver for cstates
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klog.V(1).InfoS("intel_idle driver is not in use", "currentIdleDriver", d)
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return cstate, nil
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}
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data, err := os.ReadFile(hostpath.SysfsDir.Path("module/intel_idle/parameters/max_cstate"))
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if err != nil {
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return cstate, fmt.Errorf("cannot determine cstate from max_cstates: %w", err)
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}
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cstates, err := strconv.Atoi(strings.TrimSpace(string(data)))
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if err != nil {
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return cstate, fmt.Errorf("non-integer value of cstates: %w", err)
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}
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cstate["enabled"] = strconv.FormatBool(cstates > 0)
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return cstate, nil
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}
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