tidb cpu_posix 代码
文件路径：/util/cpu_posix.go
/ Copyright 2022 PingCAP, Inc.
/
/ Licensed under the Apache License, Version 2.0 (the "License");
/ you may not use this file except in compliance with the License.
/ You may obtain a copy of the License at
/
/ http://www.apache.org/licenses/LICENSE-2.0
/
/ Unless required by applicable law or agreed to in writing, software
/ distributed under the License is distributed on an "AS IS" BASIS,
/ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/ See the License for the specific language governing permissions and
/ limitations under the License.
/go:build linux || darwin || freebsd || unix
package util
import (
"syscall"
"time"
)
var (
lastInspectUnixNano int64
lastCPUUsageTime int64
)
/ GetCPUPercentage calculates CPU usage and returns percentage in float64(e.g. 2.5 means 2.5%).
/ http://man7.org/linux/man-pages/man2/getrusage.2.html
func GetCPUPercentage() float64 {
var ru syscall.Rusage
_ = syscall.Getrusage(syscall.RUSAGE_SELF, &ru)
usageTime := ru.Utime.Nano() + ru.Stime.Nano()
nowTime := time.Now().UnixNano()
perc := float64(usageTime-lastCPUUsageTime) / float64(nowTime-lastInspectUnixNano) * 100.0
lastInspectUnixNano = nowTime
lastCPUUsageTime = usageTime
return perc
}