mirror of
https://github.com/kubernetes-sigs/node-feature-discovery.git
synced 2024-12-14 11:57:51 +00:00
77 lines
2.2 KiB
Go
77 lines
2.2 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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"os"
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"strconv"
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"strings"
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"sigs.k8s.io/node-feature-discovery/pkg/cpuid"
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"sigs.k8s.io/node-feature-discovery/source"
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)
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const (
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// CPUID EAX input values
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LEAF_PROCESSOR_FREQUENCY_INFORMATION = 0x16
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)
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func discoverSSTBF() (bool, error) {
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// Get processor's "nominal base frequency" (in MHz) from CPUID
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freqInfo := cpuid.Cpuid(LEAF_PROCESSOR_FREQUENCY_INFORMATION, 0)
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nominalBaseFrequency := int(freqInfo.EAX)
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// Loop over all CPUs in the system
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files, err := ioutil.ReadDir(source.SysfsDir.Path("bus/cpu/devices"))
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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 effective base frequency of each cpu in the system
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filePath := source.SysfsDir.Path("bus/cpu/devices", file.Name(), "cpufreq/base_frequency")
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data, err := ioutil.ReadFile(filePath)
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if os.IsNotExist(err) {
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// Ignore missing file and continue to check other CPUs
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continue
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} else if err != nil {
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return false, err
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}
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effectiveBaseFreq, err := strconv.Atoi(strings.TrimSpace(string(data)))
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if err != nil {
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return false, fmt.Errorf("non-integer value of %q: %v", filePath, err)
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}
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// Sanity check: Return an error (we don't have enough information to
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// make a decision) if we were able to read effective base frequency,
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// but, CPUID didn't support frequency info
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if nominalBaseFrequency == 0 {
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return false, fmt.Errorf("failed to determine if SST-BF is enabled: nominal base frequency info is missing")
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}
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// If the effective base freq of a CPU is greater than the nominal
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// base freq, we determine that SST-BF has been enabled
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if effectiveBaseFreq/1000 > nominalBaseFrequency {
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return true, nil
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}
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}
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return false, nil
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}
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