mirror of
https://github.com/kubernetes-sigs/node-feature-discovery.git
synced 2024-12-14 11:57:51 +00:00
da2cb07c64
Currently, it only detects one feature, i.e. hardware multithreading (such as Intel hyper-threading technology). The corresponding feature label is: feature.node.kubernetes.io/cpu-hardware_multithreading=true However, this (architecture/platform dependent) feature is not detected directly, and, the heuristics can be mislead. Detection works by checking the thread siblings of each logical (and online) cpu in the system. If any cpu has any thread siblings the feature label is set to true. Thus, hardware multithreading could be effectively disabled e.g. by putting all sibling cpus offline (even if the technology would be enabled in hardware).
68 lines
1.7 KiB
Go
68 lines
1.7 KiB
Go
/*
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Copyright 2018 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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"io/ioutil"
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"path"
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"sigs.k8s.io/node-feature-discovery/source"
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)
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// Implement FeatureSource interface
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type Source struct{}
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func (s Source) Name() string { return "cpu" }
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func (s Source) Discover() (source.Features, error) {
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features := source.Features{}
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// Check if hyper-threading seems to be enabled
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found, err := haveThreadSiblings()
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if err != nil {
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return nil, fmt.Errorf("Failed to detect hyper-threading: %v", err)
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} else if found {
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features["hardware_multithreading"] = true
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}
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return features, nil
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}
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// Check if any (online) CPUs have thread siblings
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func haveThreadSiblings() (bool, error) {
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const baseDir = "/sys/bus/cpu/devices"
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files, err := ioutil.ReadDir(baseDir)
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if err != nil {
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return false, err
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}
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for _, file := range files {
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// Try to read siblings from topology
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siblings, err := ioutil.ReadFile(path.Join(baseDir, file.Name(), "topology/thread_siblings_list"))
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if err != nil {
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return false, err
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}
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for _, char := range siblings {
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// If list separator found, we determine that there are multiple siblings
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if char == ',' || char == '-' {
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return true, nil
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}
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}
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}
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// No siblings were found
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return false, nil
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}
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