121 lines
2.6 KiB
Go
121 lines
2.6 KiB
Go
// Copyright 2018 Tobias Klauser
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package numcpus
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import (
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"io/ioutil"
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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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"golang.org/x/sys/unix"
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)
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const sysfsCPUBasePath = "/sys/devices/system/cpu"
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func getFromCPUAffinity() (int, error) {
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var cpuSet unix.CPUSet
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if err := unix.SchedGetaffinity(0, &cpuSet); err != nil {
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return 0, err
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}
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return cpuSet.Count(), nil
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}
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func readCPURange(file string) (int, error) {
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buf, err := ioutil.ReadFile(filepath.Join(sysfsCPUBasePath, file))
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if err != nil {
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return 0, err
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}
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return parseCPURange(strings.Trim(string(buf), "\n "))
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}
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func parseCPURange(cpus string) (int, error) {
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n := int(0)
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for _, cpuRange := range strings.Split(cpus, ",") {
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if len(cpuRange) == 0 {
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continue
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}
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rangeOp := strings.SplitN(cpuRange, "-", 2)
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first, err := strconv.ParseUint(rangeOp[0], 10, 32)
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if err != nil {
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return 0, err
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}
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if len(rangeOp) == 1 {
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n++
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continue
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}
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last, err := strconv.ParseUint(rangeOp[1], 10, 32)
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if err != nil {
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return 0, err
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}
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n += int(last - first + 1)
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}
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return n, nil
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}
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func getConfigured() (int, error) {
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d, err := os.Open(sysfsCPUBasePath)
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if err != nil {
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return 0, err
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}
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defer d.Close()
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fis, err := d.Readdir(-1)
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if err != nil {
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return 0, err
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}
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count := 0
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for _, fi := range fis {
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if name := fi.Name(); fi.IsDir() && strings.HasPrefix(name, "cpu") {
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_, err := strconv.ParseInt(name[3:], 10, 64)
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if err == nil {
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count++
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}
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}
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}
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return count, nil
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}
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func getKernelMax() (int, error) {
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buf, err := ioutil.ReadFile(filepath.Join(sysfsCPUBasePath, "kernel_max"))
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if err != nil {
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return 0, err
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}
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n, err := strconv.ParseInt(strings.Trim(string(buf), "\n "), 10, 32)
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if err != nil {
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return 0, err
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}
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return int(n), nil
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}
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func getOffline() (int, error) {
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return readCPURange("offline")
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}
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func getOnline() (int, error) {
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if n, err := getFromCPUAffinity(); err == nil {
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return n, nil
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}
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return readCPURange("online")
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}
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func getPossible() (int, error) {
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return readCPURange("possible")
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}
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func getPresent() (int, error) {
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return readCPURange("present")
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}
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