mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-20 23:46:23 +01:00
104 lines
2.2 KiB
Go
104 lines
2.2 KiB
Go
package cgroup
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import (
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"io/ioutil"
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"os"
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"runtime"
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"strconv"
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"strings"
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"sync"
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)
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// AvailableCPUs returns the number of available CPU cores for the app.
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func AvailableCPUs() int {
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availableCPUsOnce.Do(updateGOMAXPROCSToCPUQuota)
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return runtime.GOMAXPROCS(-1)
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}
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var availableCPUsOnce sync.Once
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// updateGOMAXPROCSToCPUQuota updates GOMAXPROCS to cgroup CPU quota if GOMAXPROCS isn't set in environment var.
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func updateGOMAXPROCSToCPUQuota() {
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if v := os.Getenv("GOMAXPROCS"); v != "" {
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// Do not override explicitly set GOMAXPROCS.
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return
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}
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q := getCPUQuota()
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if q <= 0 {
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// Do not change GOMAXPROCS
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return
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}
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gomaxprocs := int(q + 0.5)
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numCPU := runtime.NumCPU()
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if gomaxprocs > numCPU {
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// There is no sense in setting more GOMAXPROCS than the number of available CPU cores.
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return
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}
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if gomaxprocs <= 0 {
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gomaxprocs = 1
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}
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runtime.GOMAXPROCS(gomaxprocs)
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}
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func getCPUQuota() float64 {
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quotaUS, err := getCPUStat("cpu.cfs_quota_us")
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if err != nil {
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return 0
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}
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if quotaUS <= 0 {
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// The quota isn't set. This may be the case in multilevel containers.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
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return getOnlineCPUCount()
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}
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periodUS, err := getCPUStat("cpu.cfs_period_us")
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if err != nil {
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return 0
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}
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return float64(quotaUS) / float64(periodUS)
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}
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func getCPUStat(statName string) (int64, error) {
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return getStatGeneric(statName, "/sys/fs/cgroup/cpu", "/proc/self/cgroup", "cpu,")
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}
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func getOnlineCPUCount() float64 {
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
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data, err := ioutil.ReadFile("/sys/devices/system/cpu/online")
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if err != nil {
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return -1
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}
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n := float64(countCPUs(string(data)))
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if n <= 0 {
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return -1
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}
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return n
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}
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func countCPUs(data string) int {
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data = strings.TrimSpace(data)
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n := 0
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for _, s := range strings.Split(data, ",") {
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n++
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if !strings.Contains(s, "-") {
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if _, err := strconv.Atoi(s); err != nil {
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return -1
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}
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continue
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}
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bounds := strings.Split(s, "-")
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if len(bounds) != 2 {
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return -1
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}
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start, err := strconv.Atoi(bounds[0])
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if err != nil {
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return -1
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}
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end, err := strconv.Atoi(bounds[1])
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if err != nil {
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return -1
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}
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n += end - start
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}
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return n
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}
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