Files
livekit/pkg/sfu/streamallocator/nacktracker.go
Raja Subramanian 5b34d754e0 Safe access of sequencer (#1625)
* log some NACKs

* split out NACK tracker

* remove debug

* debug

* Sequencer safety

* Clean up
2023-04-17 13:02:24 +05:30

88 lines
2.1 KiB
Go

package streamallocator
import (
"fmt"
"time"
"github.com/livekit/protocol/logger"
)
// ------------------------------------------------
type NackTrackerParams struct {
Name string
Logger logger.Logger
WindowMinDuration time.Duration
WindowMaxDuration time.Duration
RatioThreshold float64
}
type NackTracker struct {
params NackTrackerParams
windowStartTime time.Time
packets uint32
repeatedNacks uint32
}
func NewNackTracker(params NackTrackerParams) *NackTracker {
return &NackTracker{
params: params,
}
}
func (n *NackTracker) Add(packets uint32, repeatedNacks uint32) {
if n.params.WindowMaxDuration != 0 && !n.windowStartTime.IsZero() && time.Since(n.windowStartTime) > n.params.WindowMaxDuration {
n.windowStartTime = time.Time{}
n.packets = 0
n.repeatedNacks = 0
}
//
// Start NACK monitoring window only when a repeated NACK happens.
// This allows locking tightly to when NACKs start happening and
// check if the NACKs keep adding up (potentially a sign of congestion)
// or isolated losses
//
if n.repeatedNacks == 0 && repeatedNacks != 0 {
n.windowStartTime = time.Now()
}
if !n.windowStartTime.IsZero() {
n.packets += packets
n.repeatedNacks += repeatedNacks
}
}
func (n *NackTracker) GetRatio() float64 {
ratio := 0.0
if n.packets != 0 {
ratio = float64(n.repeatedNacks) / float64(n.packets)
if ratio > 1.0 {
ratio = 1.0
}
}
return ratio
}
func (n *NackTracker) IsTriggered() bool {
if n.params.WindowMinDuration != 0 && !n.windowStartTime.IsZero() && time.Since(n.windowStartTime) > n.params.WindowMinDuration {
return n.GetRatio() > n.params.RatioThreshold
}
return false
}
func (n *NackTracker) ToString() string {
window := ""
if !n.windowStartTime.IsZero() {
now := time.Now()
elapsed := now.Sub(n.windowStartTime).Seconds()
window = fmt.Sprintf("t: %+v|%+v|%.2fs", n.windowStartTime.Format(time.UnixDate), now.Format(time.UnixDate), elapsed)
}
return fmt.Sprintf("n: %s, t: %s, p: %d, rn: %d, rn/p: %.2f", n.params.Name, window, n.packets, n.repeatedNacks, n.GetRatio())
}
// ------------------------------------------------