mirror of https://github.com/jech/galene.git
79 lines
2.2 KiB
Go
79 lines
2.2 KiB
Go
// Package estimator implements a packet and byte rate estimator.
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package estimator
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import (
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"sync/atomic"
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"time"
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"github.com/jech/galene/rtptime"
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)
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type Estimator struct {
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interval uint64
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time uint64
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bytes uint32
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packets uint32
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totalBytes uint32
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totalPackets uint32
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rate uint32
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packetRate uint32
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}
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// New creates a new estimator that estimates rate over the last interval.
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func New(interval time.Duration) *Estimator {
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return &Estimator{
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interval: rtptime.FromDuration(interval, rtptime.JiffiesPerSec),
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time: rtptime.Now(rtptime.JiffiesPerSec),
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}
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}
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func (e *Estimator) swap(now uint64) {
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tm := atomic.LoadUint64(&e.time)
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jiffies := now - tm
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bytes := atomic.SwapUint32(&e.bytes, 0)
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packets := atomic.SwapUint32(&e.packets, 0)
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atomic.AddUint32(&e.totalBytes, bytes)
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atomic.AddUint32(&e.totalPackets, packets)
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var rate, packetRate uint32
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if jiffies >= rtptime.JiffiesPerSec/1000 {
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rate = uint32(uint64(bytes) * rtptime.JiffiesPerSec / jiffies)
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packetRate =
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uint32(uint64(packets) * rtptime.JiffiesPerSec / jiffies)
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}
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atomic.StoreUint32(&e.rate, rate)
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atomic.StoreUint32(&e.packetRate, packetRate)
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atomic.StoreUint64(&e.time, now)
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}
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// Accumulate records one packet of size bytes
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func (e *Estimator) Accumulate(bytes uint32) {
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atomic.AddUint32(&e.bytes, bytes)
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atomic.AddUint32(&e.packets, 1)
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}
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func (e *Estimator) estimate(now uint64) (uint32, uint32) {
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tm := atomic.LoadUint64(&e.time)
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if now < tm || now-tm > e.interval {
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e.swap(now)
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}
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return atomic.LoadUint32(&e.rate), atomic.LoadUint32(&e.packetRate)
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}
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// Estimate returns an estimate of the rate over the last interval.
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// It starts a new interval if the last interval is larger than the value
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// passed to New. It returns the byte rate and the packet rate, in units
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// per second.
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func (e *Estimator) Estimate() (uint32, uint32) {
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return e.estimate(rtptime.Now(rtptime.JiffiesPerSec))
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}
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// Totals returns the total number of bytes and packets accumulated.
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func (e *Estimator) Totals() (uint32, uint32) {
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b := atomic.LoadUint32(&e.totalBytes) + atomic.LoadUint32(&e.bytes)
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p := atomic.LoadUint32(&e.totalPackets) + atomic.LoadUint32(&e.packets)
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return p, b
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}
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