52 lines
1.1 KiB
Go
52 lines
1.1 KiB
Go
package stats
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import (
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"runtime"
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"time"
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)
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// CpuStats calculates cpu usage percentage
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type CpuStats struct {
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prevCpuTime float64
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prevTime time.Time
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totalCpus int
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}
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// NewCpuStats returns a cpu stats calculator
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func NewCpuStats() *CpuStats {
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numCpus := runtime.NumCPU()
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return &CpuStats{totalCpus: numCpus}
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}
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// Percent calculates the cpu usage percentage based on the current cpu usage
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// and the previous cpu usage where usage is given as time in nanoseconds spend
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// in the cpu
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func (c *CpuStats) Percent(cpuTime float64) float64 {
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now := time.Now()
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if c.prevCpuTime == 0.0 {
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// invoked first time
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c.prevCpuTime = cpuTime
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c.prevTime = now
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return 0.0
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}
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timeDelta := now.Sub(c.prevTime).Nanoseconds()
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ret := c.calculatePercent(c.prevCpuTime, cpuTime, timeDelta)
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c.prevCpuTime = cpuTime
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c.prevTime = now
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return ret
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}
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func (c *CpuStats) calculatePercent(t1, t2 float64, timeDelta int64) float64 {
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vDelta := t2 - t1
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if timeDelta <= 0 || vDelta <= 0.0 {
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return 0.0
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}
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overall_percent := (vDelta / float64(timeDelta)) * 100.0
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return overall_percent
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}
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