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f526c7814e
This reduces memory usage under production workloads by up to 10%, while CPU spent on GC remains roughly the same. The CPU spent on GC can be monitored with go_memstats_gc_cpu_fraction metric
89 lines
2.5 KiB
Go
89 lines
2.5 KiB
Go
package cgroup
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import (
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"os"
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"runtime/debug"
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"strconv"
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)
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// GetGOGC returns GOGC value for the currently running process.
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//
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// See https://golang.org/pkg/runtime/#hdr-Environment_Variables for more details about GOGC
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func GetGOGC() int {
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return gogc
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}
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func init() {
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initGOGC()
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}
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func initGOGC() {
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if v := os.Getenv("GOGC"); v != "" {
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n, err := strconv.ParseFloat(v, 64)
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if err != nil {
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n = 100
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}
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gogc = int(n)
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} else {
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// Use lower GOGC if it isn't set yet.
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// This should reduce memory usage for typical workloads for VictoriaMetrics components
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// at the cost of increased CPU usage.
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// It is recommended increasing GOGC if go_memstats_gc_cpu_fraction exceeds 0.05 for extended periods of time.
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gogc = 30
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debug.SetGCPercent(gogc)
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}
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}
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var gogc int
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// GetMemoryLimit returns cgroup memory limit
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func GetMemoryLimit() int64 {
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// Try determining the amount of memory inside docker container.
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// See https://stackoverflow.com/questions/42187085/check-mem-limit-within-a-docker-container
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//
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// Read memory limit according to https://unix.stackexchange.com/questions/242718/how-to-find-out-how-much-memory-lxc-container-is-allowed-to-consume
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// This should properly determine the limit inside lxc container.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/84
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n, err := getMemStat("memory.limit_in_bytes")
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if err == nil {
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return n
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}
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n, err = getMemStatV2("memory.max")
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if err != nil {
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return 0
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}
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return n
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}
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func getMemStatV2(statName string) (int64, error) {
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// See https: //www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html#memory-interface-files
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return getStatGeneric(statName, "/sys/fs/cgroup", "/proc/self/cgroup", "")
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}
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func getMemStat(statName string) (int64, error) {
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return getStatGeneric(statName, "/sys/fs/cgroup/memory", "/proc/self/cgroup", "memory")
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}
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// GetHierarchicalMemoryLimit returns hierarchical memory limit
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// https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt
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func GetHierarchicalMemoryLimit() int64 {
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/699
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n, err := getHierarchicalMemoryLimit("/sys/fs/cgroup/memory", "/proc/self/cgroup")
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if err != nil {
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return 0
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}
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return n
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}
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func getHierarchicalMemoryLimit(sysfsPrefix, cgroupPath string) (int64, error) {
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data, err := getFileContents("memory.stat", sysfsPrefix, cgroupPath, "memory")
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if err != nil {
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return 0, err
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}
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memStat, err := grepFirstMatch(data, "hierarchical_memory_limit", 1, " ")
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if err != nil {
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return 0, err
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}
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return strconv.ParseInt(memStat, 10, 64)
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}
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