From ae161b3bb754b691df1997e26d9a3ccf16dc7434 Mon Sep 17 00:00:00 2001 From: Mathis Engelbart Date: Fri, 17 Jan 2025 17:15:30 +0100 Subject: [PATCH] Refactor GCC --- go.mod | 2 +- pkg/bwe/acknowledgment.go | 38 ++++ pkg/bwe/arrival_group_accumulator.go | 48 +++++ pkg/bwe/arrival_group_accumulator_test.go | 239 +++++++++++++++++++++ pkg/bwe/delay_rate_controller.go | 81 +++++++ pkg/bwe/delivery_rate_estimator.go | 87 ++++++++ pkg/bwe/delivery_rate_estimator_test.go | 74 +++++++ pkg/bwe/exponential_moving_average.go | 19 ++ pkg/bwe/exponential_moving_average_test.go | 122 +++++++++++ pkg/bwe/kalman.go | 92 ++++++++ pkg/bwe/loss_rate_controller.go | 53 +++++ pkg/bwe/loss_rate_controller_test.go | 86 ++++++++ pkg/bwe/overuse_detector.go | 84 ++++++++ pkg/bwe/overuse_detector_test.go | 186 ++++++++++++++++ pkg/bwe/rate_controller.go | 76 +++++++ pkg/bwe/rate_controller_test.go | 143 ++++++++++++ pkg/bwe/rtt.go | 8 + pkg/bwe/send_side_bwe.go | 46 ++++ pkg/bwe/state.go | 59 +++++ pkg/bwe/state_test.go | 27 +++ pkg/bwe/usage.go | 24 +++ 21 files changed, 1593 insertions(+), 1 deletion(-) create mode 100644 pkg/bwe/acknowledgment.go create mode 100644 pkg/bwe/arrival_group_accumulator.go create mode 100644 pkg/bwe/arrival_group_accumulator_test.go create mode 100644 pkg/bwe/delay_rate_controller.go create mode 100644 pkg/bwe/delivery_rate_estimator.go create mode 100644 pkg/bwe/delivery_rate_estimator_test.go create mode 100644 pkg/bwe/exponential_moving_average.go create mode 100644 pkg/bwe/exponential_moving_average_test.go create mode 100644 pkg/bwe/kalman.go create mode 100644 pkg/bwe/loss_rate_controller.go create mode 100644 pkg/bwe/loss_rate_controller_test.go create mode 100644 pkg/bwe/overuse_detector.go create mode 100644 pkg/bwe/overuse_detector_test.go create mode 100644 pkg/bwe/rate_controller.go create mode 100644 pkg/bwe/rate_controller_test.go create mode 100644 pkg/bwe/rtt.go create mode 100644 pkg/bwe/send_side_bwe.go create mode 100644 pkg/bwe/state.go create mode 100644 pkg/bwe/state_test.go create mode 100644 pkg/bwe/usage.go diff --git a/go.mod b/go.mod index e870e266..1a1652d1 100644 --- a/go.mod +++ b/go.mod @@ -1,6 +1,6 @@ module github.com/pion/interceptor -go 1.20 +go 1.21 require ( github.com/pion/logging v0.2.3 diff --git a/pkg/bwe/acknowledgment.go b/pkg/bwe/acknowledgment.go new file mode 100644 index 00000000..7a241d92 --- /dev/null +++ b/pkg/bwe/acknowledgment.go @@ -0,0 +1,38 @@ +package bwe + +import ( + "fmt" + "time" +) + +type ECN uint8 + +const ( + //nolint:misspell + // ECNNonECT signals Non ECN-Capable Transport, Non-ECT + ECNNonECT ECN = iota // 00 + + //nolint:misspell + // ECNECT1 signals ECN Capable Transport, ECT(0) + ECNECT1 // 01 + + //nolint:misspell + // ECNECT0 signals ECN Capable Transport, ECT(1) + ECNECT0 // 10 + + // ECNCE signals ECN Congestion Encountered, CE + ECNCE // 11 +) + +type Acknowledgment struct { + SeqNr int64 + Size uint16 + Departure time.Time + Arrived bool + Arrival time.Time + ECN ECN +} + +func (a Acknowledgment) String() string { + return fmt.Sprintf("seq=%v, departure=%v, arrival=%v", a.SeqNr, a.Departure, a.Arrival) +} diff --git a/pkg/bwe/arrival_group_accumulator.go b/pkg/bwe/arrival_group_accumulator.go new file mode 100644 index 00000000..088d3fda --- /dev/null +++ b/pkg/bwe/arrival_group_accumulator.go @@ -0,0 +1,48 @@ +package bwe + +import ( + "time" +) + +type arrivalGroup []Acknowledgment + +type arrivalGroupAccumulator struct { + next arrivalGroup + burstInterval time.Duration + maxBurstDuration time.Duration +} + +func newArrivalGroupAccumulator() *arrivalGroupAccumulator { + return &arrivalGroupAccumulator{ + next: make([]Acknowledgment, 0), + burstInterval: 5 * time.Millisecond, + maxBurstDuration: 100 * time.Millisecond, + } +} + +func (a *arrivalGroupAccumulator) onPacketAcked(ack Acknowledgment) arrivalGroup { + if len(a.next) == 0 { + a.next = append(a.next, ack) + return nil + } + + if ack.Departure.Sub(a.next[0].Departure) < a.burstInterval { + a.next = append(a.next, ack) + return nil + } + + sendTimeDelta := ack.Departure.Sub(a.next[0].Departure) + arrivalTimeDeltaLast := ack.Arrival.Sub(a.next[len(a.next)-1].Arrival) + arrivalTimeDeltaFirst := ack.Arrival.Sub(a.next[0].Arrival) + propagationDelta := arrivalTimeDeltaFirst - sendTimeDelta + + if propagationDelta < 0 && arrivalTimeDeltaLast <= a.burstInterval && arrivalTimeDeltaFirst < a.maxBurstDuration { + a.next = append(a.next, ack) + return nil + } + + group := make(arrivalGroup, len(a.next)) + copy(group, a.next) + a.next = arrivalGroup{ack} + return group +} diff --git a/pkg/bwe/arrival_group_accumulator_test.go b/pkg/bwe/arrival_group_accumulator_test.go new file mode 100644 index 00000000..e88cb3b8 --- /dev/null +++ b/pkg/bwe/arrival_group_accumulator_test.go @@ -0,0 +1,239 @@ +package bwe + +import ( + "testing" + "time" + + "github.com/stretchr/testify/assert" +) + +func TestArrivalGroupAccumulator(t *testing.T) { + triggerNewGroupElement := Acknowledgment{ + Departure: time.Time{}.Add(time.Second), + Arrival: time.Time{}.Add(time.Second), + } + cases := []struct { + name string + log []Acknowledgment + exp []arrivalGroup + }{ + { + name: "emptyCreatesNoGroups", + log: []Acknowledgment{}, + exp: []arrivalGroup{}, + }, + { + name: "createsSingleElementGroup", + log: []Acknowledgment{ + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(time.Millisecond), + }, + triggerNewGroupElement, + }, + exp: []arrivalGroup{{ + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(time.Millisecond), + }, + }, + }, + }, + { + name: "createsTwoElementGroup", + log: []Acknowledgment{ + { + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(20 * time.Millisecond), + }, + triggerNewGroupElement, + }, + exp: []arrivalGroup{{ + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(20 * time.Millisecond), + }, + }}, + }, + { + name: "createsTwoArrivalGroups1", + log: []Acknowledgment{ + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(20 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(9 * time.Millisecond), + Arrival: time.Time{}.Add(24 * time.Millisecond), + }, + triggerNewGroupElement, + }, + exp: []arrivalGroup{ + { + { + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(20 * time.Millisecond), + }, + }, + { + { + Departure: time.Time{}.Add(9 * time.Millisecond), + Arrival: time.Time{}.Add(24 * time.Millisecond), + }, + }, + }, + }, + { + name: "createsTwoArrivalGroups2", + log: []Acknowledgment{ + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(20 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(9 * time.Millisecond), + Arrival: time.Time{}.Add(30 * time.Millisecond), + }, + triggerNewGroupElement, + }, + exp: []arrivalGroup{ + { + { + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(20 * time.Millisecond), + }, + }, + { + { + Departure: time.Time{}.Add(9 * time.Millisecond), + Arrival: time.Time{}.Add(30 * time.Millisecond), + }, + }, + }, + }, + { + name: "ignoresOutOfOrderPackets", + log: []Acknowledgment{ + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(6 * time.Millisecond), + Arrival: time.Time{}.Add(34 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(8 * time.Millisecond), + Arrival: time.Time{}.Add(30 * time.Millisecond), + }, + triggerNewGroupElement, + }, + exp: []arrivalGroup{ + { + { + Departure: time.Time{}, + Arrival: time.Time{}.Add(15 * time.Millisecond), + }, + }, + { + { + Departure: time.Time{}.Add(6 * time.Millisecond), + Arrival: time.Time{}.Add(34 * time.Millisecond), + }, + { + Departure: time.Time{}.Add(8 * time.Millisecond), + Arrival: time.Time{}.Add(30 * time.Millisecond), + }, + }, + }, + }, + { + name: "newGroupBecauseOfInterDepartureTime", + log: []Acknowledgment{ + { + SeqNr: 0, + Departure: time.Time{}, + Arrival: time.Time{}.Add(4 * time.Millisecond), + }, + { + SeqNr: 1, + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(4 * time.Millisecond), + }, + { + SeqNr: 2, + Departure: time.Time{}.Add(6 * time.Millisecond), + Arrival: time.Time{}.Add(10 * time.Millisecond), + }, + { + SeqNr: 3, + Departure: time.Time{}.Add(9 * time.Millisecond), + Arrival: time.Time{}.Add(10 * time.Millisecond), + }, + triggerNewGroupElement, + }, + exp: []arrivalGroup{ + { + { + SeqNr: 0, + Departure: time.Time{}, + Arrival: time.Time{}.Add(4 * time.Millisecond), + }, + { + SeqNr: 1, + Departure: time.Time{}.Add(3 * time.Millisecond), + Arrival: time.Time{}.Add(4 * time.Millisecond), + }, + }, + { + { + SeqNr: 2, + Departure: time.Time{}.Add(6 * time.Millisecond), + Arrival: time.Time{}.Add(10 * time.Millisecond), + }, + { + SeqNr: 3, + Departure: time.Time{}.Add(9 * time.Millisecond), + Arrival: time.Time{}.Add(10 * time.Millisecond), + }, + }, + }, + }, + } + + for _, tc := range cases { + tc := tc + t.Run(tc.name, func(t *testing.T) { + aga := newArrivalGroupAccumulator() + received := []arrivalGroup{} + for _, ack := range tc.log { + next := aga.onPacketAcked(ack) + if next != nil { + received = append(received, next) + } + } + assert.Equal(t, tc.exp, received) + }) + } +} diff --git a/pkg/bwe/delay_rate_controller.go b/pkg/bwe/delay_rate_controller.go new file mode 100644 index 00000000..b45b40da --- /dev/null +++ b/pkg/bwe/delay_rate_controller.go @@ -0,0 +1,81 @@ +package bwe + +import ( + "log" + "time" +) + +const maxSamples = 1000 + +type DelayRateController struct { + aga *arrivalGroupAccumulator + last arrivalGroup + kf *kalmanFilter + od *overuseDetector + rc *rateController + latestUsage usage + samples int +} + +func NewDelayRateController(initialRate int) *DelayRateController { + return &DelayRateController{ + aga: newArrivalGroupAccumulator(), + last: []Acknowledgment{}, + kf: newKalmanFilter(), + od: newOveruseDetector(true), + rc: newRateController(initialRate), + } +} + +func (c *DelayRateController) OnPacketAcked(ack Acknowledgment) { + next := c.aga.onPacketAcked(ack) + if next == nil { + return + } + if len(next) == 0 { + // ignore empty groups, should never occur + return + } + if len(c.last) == 0 { + c.last = next + return + } + + prevSize := groupSize(c.last) + nextSize := groupSize(next) + sizeDelta := nextSize - prevSize + + interArrivalTime := next[len(next)-1].Arrival.Sub(c.last[len(c.last)-1].Arrival) + interDepartureTime := next[len(next)-1].Departure.Sub(c.last[len(c.last)-1].Departure) + interGroupDelay := interArrivalTime - interDepartureTime + estimate := c.kf.update(float64(interGroupDelay.Milliseconds()), float64(sizeDelta)) + c.samples++ + c.latestUsage = c.od.update(ack.Arrival, estimate, c.samples) + c.last = next + log.Printf( + "ts=%v.%06d, seq=%v, size=%v, interArrivalTime=%v, interDepartureTime=%v, interGroupDelay=%v, estimate=%v, threshold=%v, usage=%v, state=%v", + c.last[0].Departure.UTC().Format("2006/01/02 15:04:05"), + c.last[0].Departure.UTC().Nanosecond()/1e3, + next[0].SeqNr, + nextSize, + interArrivalTime.Microseconds(), + interDepartureTime.Microseconds(), + interGroupDelay.Microseconds(), + estimate, + c.od.delayThreshold, + int(c.latestUsage), + int(c.rc.s), + ) +} + +func (c *DelayRateController) Update(ts time.Time, lastDeliveryRate int, rtt time.Duration) int { + return c.rc.update(ts, c.latestUsage, lastDeliveryRate, rtt) +} + +func groupSize(group arrivalGroup) int { + sum := 0 + for _, ack := range group { + sum += int(ack.Size) + } + return sum +} diff --git a/pkg/bwe/delivery_rate_estimator.go b/pkg/bwe/delivery_rate_estimator.go new file mode 100644 index 00000000..9d18e3a7 --- /dev/null +++ b/pkg/bwe/delivery_rate_estimator.go @@ -0,0 +1,87 @@ +package bwe + +import ( + "container/heap" + "time" +) + +type deliveryRateHeapItem struct { + arrival time.Time + size int +} + +type deliveryRateHeap []deliveryRateHeapItem + +// Len implements heap.Interface. +func (d deliveryRateHeap) Len() int { + return len(d) +} + +// Less implements heap.Interface. +func (d deliveryRateHeap) Less(i int, j int) bool { + return d[i].arrival.Before(d[j].arrival) +} + +// Pop implements heap.Interface. +func (d *deliveryRateHeap) Pop() any { + old := *d + n := len(old) + x := old[n-1] + *d = old[0 : n-1] + return x +} + +// Push implements heap.Interface. +func (d *deliveryRateHeap) Push(x any) { + *d = append(*d, x.(deliveryRateHeapItem)) +} + +// Swap implements heap.Interface. +func (d deliveryRateHeap) Swap(i int, j int) { + d[i], d[j] = d[j], d[i] +} + +type deliveryRateEstimator struct { + window time.Duration + latestArrival time.Time + history *deliveryRateHeap +} + +func newDeliveryRateEstimator(window time.Duration) *deliveryRateEstimator { + return &deliveryRateEstimator{ + window: window, + latestArrival: time.Time{}, + history: &deliveryRateHeap{}, + } +} + +func (e *deliveryRateEstimator) OnPacketAcked(arrival time.Time, size int) { + if arrival.After(e.latestArrival) { + e.latestArrival = arrival + } + heap.Push(e.history, deliveryRateHeapItem{ + arrival: arrival, + size: size, + }) +} + +func (e *deliveryRateEstimator) GetRate() int { + deadline := e.latestArrival.Add(-e.window) + for len(*e.history) > 0 && (*e.history)[0].arrival.Before(deadline) { + heap.Pop(e.history) + } + earliest := e.latestArrival + sum := 0 + for _, i := range *e.history { + if i.arrival.Before(earliest) { + earliest = i.arrival + } + sum += i.size + } + d := e.latestArrival.Sub(earliest) + if d == 0 { + return 0 + } + rate := 8 * float64(sum) / d.Seconds() + return int(rate) +} diff --git a/pkg/bwe/delivery_rate_estimator_test.go b/pkg/bwe/delivery_rate_estimator_test.go new file mode 100644 index 00000000..15ea3665 --- /dev/null +++ b/pkg/bwe/delivery_rate_estimator_test.go @@ -0,0 +1,74 @@ +package bwe + +import ( + "fmt" + "testing" + "time" + + "github.com/stretchr/testify/assert" +) + +func TestDeliveryRateEstimator(t *testing.T) { + type ack struct { + arrival time.Time + size int + } + cases := []struct { + window time.Duration + acks []ack + expectedRate int + }{ + { + window: 0, + acks: []ack{}, + expectedRate: 0, + }, + { + window: time.Second, + acks: []ack{}, + expectedRate: 0, + }, + { + window: time.Second, + acks: []ack{ + {time.Time{}, 1200}, + }, + expectedRate: 0, + }, + { + window: time.Second, + acks: []ack{ + {time.Time{}.Add(time.Millisecond), 1200}, + }, + expectedRate: 0, + }, + { + window: time.Second, + acks: []ack{ + {time.Time{}.Add(time.Second), 1200}, + {time.Time{}.Add(1500 * time.Millisecond), 1200}, + {time.Time{}.Add(2 * time.Second), 1200}, + }, + expectedRate: 28800, + }, + { + window: time.Second, + acks: []ack{ + {time.Time{}.Add(500 * time.Millisecond), 1200}, + {time.Time{}.Add(time.Second), 1200}, + {time.Time{}.Add(1500 * time.Millisecond), 1200}, + {time.Time{}.Add(2 * time.Second), 1200}, + }, + expectedRate: 28800, + }, + } + for i, tc := range cases { + t.Run(fmt.Sprintf("%v", i), func(t *testing.T) { + e := newDeliveryRateEstimator(tc.window) + for _, ack := range tc.acks { + e.OnPacketAcked(ack.arrival, ack.size) + } + assert.Equal(t, tc.expectedRate, e.GetRate()) + }) + } +} diff --git a/pkg/bwe/exponential_moving_average.go b/pkg/bwe/exponential_moving_average.go new file mode 100644 index 00000000..9971a1e7 --- /dev/null +++ b/pkg/bwe/exponential_moving_average.go @@ -0,0 +1,19 @@ +package bwe + +type exponentialMovingAverage struct { + initialized bool + alpha float64 + average float64 + variance float64 +} + +func (a *exponentialMovingAverage) update(sample float64) { + if !a.initialized { + a.average = sample + a.initialized = true + } else { + delta := sample - a.average + a.average = a.alpha*sample + (1-a.alpha)*a.average + a.variance = (1-a.alpha)*a.variance + a.alpha*(1-a.alpha)*(delta*delta) + } +} diff --git a/pkg/bwe/exponential_moving_average_test.go b/pkg/bwe/exponential_moving_average_test.go new file mode 100644 index 00000000..89976b51 --- /dev/null +++ b/pkg/bwe/exponential_moving_average_test.go @@ -0,0 +1,122 @@ +package bwe + +import ( + "fmt" + "testing" + + "github.com/stretchr/testify/assert" +) + +// python to generate test cases: +// import numpy as np +// import pandas as pd +// data = np.random.randint(1, 10, size=10) +// df = pd.DataFrame(data) +// expectedAvg = df.ewm(alpha=0.9, adjust=False).mean() +// expectedVar = df.ewm(alpha=0.9, adjust=False).var(bias=True) + +func TestExponentialMovingAverage(t *testing.T) { + cases := []struct { + alpha float64 + updates []float64 + expectedAvg []float64 + expectedVar []float64 + }{ + { + alpha: 0.9, + updates: []float64{}, + expectedAvg: []float64{}, + expectedVar: []float64{}, + }, + { + alpha: 0.9, + updates: []float64{1, 2, 3, 4}, + expectedAvg: []float64{ + 1.000, + 1.900, + 2.890, + 3.889, + }, + expectedVar: []float64{ + 0.000000, + 0.090000, + 0.117900, + 0.122679, + }, + }, + { + alpha: 0.9, + updates: []float64{8, 8, 5, 1, 3, 1, 8, 2, 8, 9}, + expectedAvg: []float64{ + 8.000000, + 8.000000, + 5.300000, + 1.430000, + 2.843000, + 1.184300, + 7.318430, + 2.531843, + 7.453184, + 8.845318, + }, + expectedVar: []float64{ + 0.000000, + 0.000000, + 0.810000, + 1.745100, + 0.396351, + 0.345334, + 4.215372, + 2.967250, + 2.987792, + 0.514117, + }, + }, + { + alpha: 0.9, + updates: []float64{7, 5, 6, 7, 3, 6, 8, 9, 5, 5}, + expectedAvg: []float64{ + 7.000000, + 5.200000, + 5.920000, + 6.892000, + 3.389200, + 5.738920, + 7.773892, + 8.877389, + 5.387739, + 5.038774, + }, + expectedVar: []float64{ + 0.000000, + 0.360000, + 0.093600, + 0.114336, + 1.374723, + 0.750937, + 0.535217, + 0.188822, + 1.371955, + 0.150726, + }, + }, + } + for i, tc := range cases { + t.Run(fmt.Sprintf("%v", i), func(t *testing.T) { + a := exponentialMovingAverage{ + alpha: tc.alpha, + average: 0, + variance: 0, + } + avgs := []float64{} + vars := []float64{} + for _, u := range tc.updates { + a.update(u) + avgs = append(avgs, a.average) + vars = append(vars, a.variance) + } + assert.InDeltaSlice(t, tc.expectedAvg, avgs, 0.001) + assert.InDeltaSlice(t, tc.expectedVar, vars, 0.001) + }) + } +} diff --git a/pkg/bwe/kalman.go b/pkg/bwe/kalman.go new file mode 100644 index 00000000..5aed2eb3 --- /dev/null +++ b/pkg/bwe/kalman.go @@ -0,0 +1,92 @@ +package bwe + +import ( + "math" +) + +type kalmanFilter struct { + state [2]float64 // [slope, offset] + + processNoise [2]float64 + e [2][2]float64 + avgNoise float64 + varNoise float64 +} + +type kalmanOption func(*kalmanFilter) + +func initSlope(e float64) kalmanOption { + return func(k *kalmanFilter) { + k.state[0] = e + } +} + +func newKalmanFilter(opts ...kalmanOption) *kalmanFilter { + kf := &kalmanFilter{ + state: [2]float64{8.0 / 512.0, 0}, + processNoise: [2]float64{1e-13, 1e-3}, + e: [2][2]float64{{100.0, 0}, {0, 1e-1}}, + varNoise: 50.0, + } + for _, opt := range opts { + opt(kf) + } + return kf +} + +func (k *kalmanFilter) update(timeDelta float64, sizeDelta float64) float64 { + k.e[0][0] += k.processNoise[0] + k.e[1][1] += k.processNoise[1] + + h := [2]float64{sizeDelta, 1.0} + Eh := [2]float64{ + k.e[0][0]*h[0] + k.e[0][1]*h[1], + k.e[1][0]*h[0] + k.e[1][1]*h[1], + } + residual := timeDelta - (k.state[0]*h[0] + k.state[1]*h[1]) + + maxResidual := 3.0 * math.Sqrt(k.varNoise) + if math.Abs(residual) < maxResidual { + k.updateNoiseEstimate(residual, timeDelta) + } else { + if residual < 0 { + k.updateNoiseEstimate(-maxResidual, timeDelta) + } else { + k.updateNoiseEstimate(maxResidual, timeDelta) + } + } + + denom := k.varNoise + h[0]*Eh[0] + h[1]*Eh[1] + + K := [2]float64{ + Eh[0] / denom, Eh[1] / denom, + } + + IKh := [2][2]float64{ + {1.0 - K[0]*h[0], -K[0] * h[1]}, + {-K[1] * h[0], 1.0 - K[1]*h[1]}, + } + + e00 := k.e[0][0] + e01 := k.e[0][1] + + k.e[0][0] = e00*IKh[0][0] + k.e[1][0]*IKh[0][1] + k.e[0][1] = e01*IKh[0][0] + k.e[1][1]*IKh[0][1] + k.e[1][0] = e00*IKh[1][0] + k.e[1][0]*IKh[1][1] + k.e[1][1] = e01*IKh[1][0] + k.e[1][1]*IKh[1][1] + + k.state[0] = k.state[0] + K[0]*residual + k.state[1] = k.state[1] + K[1]*residual + + return k.state[1] +} + +func (k *kalmanFilter) updateNoiseEstimate(residual float64, timeDelta float64) { + alpha := 0.002 + beta := math.Pow(1-alpha, timeDelta*30.0/1000.0) + k.avgNoise = beta*k.avgNoise + (1-beta)*residual + k.varNoise = beta*k.varNoise + (1-beta)*(k.avgNoise-residual)*(k.avgNoise-residual) + if k.varNoise < 1 { + k.varNoise = 1 + } +} diff --git a/pkg/bwe/loss_rate_controller.go b/pkg/bwe/loss_rate_controller.go new file mode 100644 index 00000000..22a37d01 --- /dev/null +++ b/pkg/bwe/loss_rate_controller.go @@ -0,0 +1,53 @@ +package bwe + +type LossRateController struct { + bitrate int + min, max float64 + + packetsSinceLastUpdate int + arrivedSinceLastUpdate int + lostSinceLastUpdate int +} + +func NewLossRateController(initialRate, minRate, maxRate int) *LossRateController { + return &LossRateController{ + bitrate: initialRate, + min: float64(minRate), + max: float64(maxRate), + packetsSinceLastUpdate: 0, + arrivedSinceLastUpdate: 0, + lostSinceLastUpdate: 0, + } +} + +func (l *LossRateController) OnPacketAcked() { + l.packetsSinceLastUpdate++ + l.arrivedSinceLastUpdate++ +} + +func (l *LossRateController) OnPacketLost() { + l.packetsSinceLastUpdate++ + l.lostSinceLastUpdate++ +} + +func (l *LossRateController) Update(lastDeliveryRate int) int { + lossRate := float64(l.lostSinceLastUpdate) / float64(l.packetsSinceLastUpdate) + var target float64 + if lossRate > 0.1 { + target = float64(l.bitrate) * (1 - 0.5*lossRate) + target = max(target, l.min) + } else if lossRate < 0.02 { + target = float64(l.bitrate) * 1.05 + target = max(min(target, 1.5*float64(lastDeliveryRate)), float64(l.bitrate)) + target = min(target, l.max) + } + if target != 0 { + l.bitrate = int(target) + } + + l.packetsSinceLastUpdate = 0 + l.arrivedSinceLastUpdate = 0 + l.lostSinceLastUpdate = 0 + + return l.bitrate +} diff --git a/pkg/bwe/loss_rate_controller_test.go b/pkg/bwe/loss_rate_controller_test.go new file mode 100644 index 00000000..2871e54f --- /dev/null +++ b/pkg/bwe/loss_rate_controller_test.go @@ -0,0 +1,86 @@ +package bwe + +import ( + "fmt" + "testing" + + "github.com/stretchr/testify/assert" +) + +func TestLossRateController(t *testing.T) { + cases := []struct { + init, min, max int + acked int + lost int + deliveredRate int + expectedRate int + }{ + {}, // all zeros + { + init: 100_000, + min: 100_000, + max: 1_000_000, + acked: 0, + lost: 0, + deliveredRate: 0, + expectedRate: 100_000, + }, + { + init: 100_000, + min: 100_000, + max: 1_000_000, + acked: 99, + lost: 1, + deliveredRate: 100_000, + expectedRate: 105_000, + }, + { + init: 100_000, + min: 100_000, + max: 1_000_000, + acked: 99, + lost: 1, + deliveredRate: 90_000, + expectedRate: 105_000, + }, + { + init: 100_000, + min: 100_000, + max: 1_000_000, + acked: 95, + lost: 5, + deliveredRate: 99_000, + expectedRate: 100_000, + }, + { + init: 100_000, + min: 50_000, + max: 1_000_000, + acked: 89, + lost: 11, + deliveredRate: 90_000, + expectedRate: 94_500, + }, + { + init: 100_000, + min: 100_000, + max: 1_000_000, + acked: 89, + lost: 11, + deliveredRate: 90_000, + expectedRate: 100_000, + }, + } + for i, tc := range cases { + t.Run(fmt.Sprintf("%v", i), func(t *testing.T) { + lrc := NewLossRateController(tc.init, tc.min, tc.max) + for i := 0; i < tc.acked; i++ { + lrc.OnPacketAcked() + } + for i := 0; i < tc.lost; i++ { + lrc.OnPacketLost() + } + assert.Equal(t, tc.expectedRate, lrc.Update(tc.deliveredRate)) + }) + } +} diff --git a/pkg/bwe/overuse_detector.go b/pkg/bwe/overuse_detector.go new file mode 100644 index 00000000..c5a3c512 --- /dev/null +++ b/pkg/bwe/overuse_detector.go @@ -0,0 +1,84 @@ +package bwe + +import ( + "math" + "time" +) + +const ( + kU = 0.01 + kD = 0.00018 + + maxNumDeltas = 60 +) + +type overuseDetector struct { + adaptiveThreshold bool + overUseTimeThreshold time.Duration + delayThreshold float64 + lastEstimate time.Duration + lastUpdate time.Time + firstOverUse time.Time + inOveruse bool + lastUsage usage +} + +func newOveruseDetector(adaptive bool) *overuseDetector { + return &overuseDetector{ + adaptiveThreshold: adaptive, + overUseTimeThreshold: 10 * time.Millisecond, + delayThreshold: 12.5, + lastEstimate: 0, + lastUpdate: time.Time{}, + firstOverUse: time.Time{}, + inOveruse: false, + } +} + +func (d *overuseDetector) update(ts time.Time, trend float64, numDeltas int) usage { + if numDeltas < 2 { + return usageNormal + } + modifiedTrend := float64(min(numDeltas, maxNumDeltas)) * trend + + if modifiedTrend > d.delayThreshold { + if d.firstOverUse.IsZero() { + d.firstOverUse = ts + } + if ts.Sub(d.firstOverUse) > d.overUseTimeThreshold { + d.firstOverUse = time.Time{} + d.lastUsage = usageOver + } + } else if modifiedTrend < -d.delayThreshold { + d.firstOverUse = time.Time{} + d.lastUsage = usageUnder + } else { + d.firstOverUse = time.Time{} + d.lastUsage = usageNormal + } + if d.adaptiveThreshold { + d.adaptThreshold(ts, modifiedTrend) + } + return d.lastUsage +} + +func (d *overuseDetector) adaptThreshold(ts time.Time, modifiedTrend float64) { + if d.lastUpdate.IsZero() { + d.lastUpdate = ts + } + if math.Abs(modifiedTrend) > d.delayThreshold+15 { + d.lastUpdate = ts + return + } + k := kU + if math.Abs(modifiedTrend) < d.delayThreshold { + k = kD + } + delta := ts.Sub(d.lastUpdate) + if delta > 100*time.Millisecond { + delta = 100 * time.Millisecond + } + d.delayThreshold += k * (math.Abs(modifiedTrend) - d.delayThreshold) * float64(delta.Milliseconds()) + d.delayThreshold = max(min(d.delayThreshold, 600.0), 6.0) + d.lastUpdate = ts +} diff --git a/pkg/bwe/overuse_detector_test.go b/pkg/bwe/overuse_detector_test.go new file mode 100644 index 00000000..5764c759 --- /dev/null +++ b/pkg/bwe/overuse_detector_test.go @@ -0,0 +1,186 @@ +package bwe + +import ( + "testing" + "time" + + "github.com/stretchr/testify/assert" +) + +func TestOveruseDetectorUpdate(t *testing.T) { + type estimate struct { + ts time.Time + estimate float64 + numDeltas int + } + cases := []struct { + name string + adaptive bool + values []estimate + expected []usage + }{ + { + name: "noEstimateNoUsageStatic", + adaptive: false, + values: []estimate{}, + expected: []usage{}, + }, + { + name: "overuseStatic", + adaptive: false, + values: []estimate{ + {time.Time{}, 1.0, 1}, + {time.Time{}.Add(5 * time.Millisecond), 20, 2}, + {time.Time{}.Add(20 * time.Millisecond), 30, 3}, + }, + expected: []usage{usageNormal, usageNormal, usageOver}, + }, + { + name: "normaluseStatic", + adaptive: false, + values: []estimate{{estimate: 0}}, + expected: []usage{usageNormal}, + }, + { + name: "underuseStatic", + adaptive: false, + values: []estimate{{time.Time{}, -20, 2}}, + expected: []usage{usageUnder}, + }, + { + name: "noOverUseBeforeDelayStatic", + adaptive: false, + values: []estimate{ + {time.Time{}.Add(time.Millisecond), 20, 1}, + {time.Time{}.Add(2 * time.Millisecond), 30, 2}, + {time.Time{}.Add(30 * time.Millisecond), 50, 3}, + }, + expected: []usage{usageNormal, usageNormal, usageOver}, + }, + { + name: "noOverUseIfEstimateDecreasedStatic", + adaptive: false, + values: []estimate{ + {time.Time{}.Add(time.Millisecond), 20, 1}, + {time.Time{}.Add(10 * time.Millisecond), 40, 2}, + {time.Time{}.Add(30 * time.Millisecond), 50, 3}, + {time.Time{}.Add(35 * time.Millisecond), 3, 4}, + }, + expected: []usage{usageNormal, usageNormal, usageOver, usageNormal}, + }, + { + name: "noEstimateNoUsageAdaptive", + adaptive: true, + values: []estimate{}, + expected: []usage{}, + }, + { + name: "overuseAdaptive", + adaptive: true, + values: []estimate{ + {time.Time{}, 1, 1}, + {time.Time{}.Add(5 * time.Millisecond), 20, 2}, + {time.Time{}.Add(20 * time.Millisecond), 30, 3}, + }, + expected: []usage{usageNormal, usageNormal, usageOver}, + }, + { + name: "normaluseAdaptive", + adaptive: true, + values: []estimate{{estimate: 0}}, + expected: []usage{usageNormal}, + }, + { + name: "underuseAdaptive", + adaptive: true, + values: []estimate{{time.Time{}, -20, 2}}, + expected: []usage{usageUnder}, + }, + { + name: "noOverUseBeforeDelayAdaptive", + adaptive: true, + values: []estimate{ + {time.Time{}.Add(time.Millisecond), 20, 1}, + {time.Time{}.Add(2 * time.Millisecond), 30, 2}, + {time.Time{}.Add(30 * time.Millisecond), 50, 3}, + }, + expected: []usage{usageNormal, usageNormal, usageOver}, + }, + { + name: "noOverUseIfEstimateDecreasedAdaptive", + adaptive: true, + values: []estimate{ + {time.Time{}.Add(time.Millisecond), 20, 1}, + {time.Time{}.Add(10 * time.Millisecond), 40, 2}, + {time.Time{}.Add(30 * time.Millisecond), 50, 3}, + {time.Time{}.Add(35 * time.Millisecond), 3, 4}, + }, + expected: []usage{usageNormal, usageNormal, usageOver, usageNormal}, + }, + } + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + od := newOveruseDetector(tc.adaptive) + received := []usage{} + for _, e := range tc.values { + usage := od.update(e.ts, e.estimate, e.numDeltas) + received = append(received, usage) + } + assert.Equal(t, tc.expected, received) + }) + } +} + +func TestOveruseDetectorAdaptThreshold(t *testing.T) { + cases := []struct { + name string + od *overuseDetector + ts time.Time + estimate float64 + expectedThreshold float64 + }{ + { + name: "minThreshold", + od: &overuseDetector{}, + ts: time.Time{}, + estimate: 0, + expectedThreshold: 6, + }, + { + name: "increase", + od: &overuseDetector{ + delayThreshold: 12.5, + lastUpdate: time.Time{}.Add(time.Second), + }, + ts: time.Time{}.Add(2 * time.Second), + estimate: 25, + expectedThreshold: 25, + }, + { + name: "maxThreshold", + od: &overuseDetector{ + delayThreshold: 6, + lastUpdate: time.Time{}, + }, + ts: time.Time{}.Add(time.Second), + estimate: 6.1, + expectedThreshold: 6, + }, + { + name: "decrease", + od: &overuseDetector{ + delayThreshold: 12.5, + lastUpdate: time.Time{}, + }, + ts: time.Time{}.Add(time.Second), + estimate: 1, + expectedThreshold: 12.5, + }, + } + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + tc.od.adaptThreshold(tc.ts, tc.estimate) + assert.Equal(t, tc.expectedThreshold, tc.od.delayThreshold) + }) + } +} diff --git a/pkg/bwe/rate_controller.go b/pkg/bwe/rate_controller.go new file mode 100644 index 00000000..e51a48c8 --- /dev/null +++ b/pkg/bwe/rate_controller.go @@ -0,0 +1,76 @@ +package bwe + +import ( + "math" + "time" +) + +type rateController struct { + s state + rate int + + decreaseFactor float64 // (beta) + lastUpdate time.Time + lastDecrease *exponentialMovingAverage +} + +func newRateController(initialRate int) *rateController { + return &rateController{ + s: stateIncrease, + rate: initialRate, + decreaseFactor: 0.85, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{}, + } +} + +func (c *rateController) update(ts time.Time, u usage, deliveredRate int, rtt time.Duration) int { + nextState := c.s.transition(u) + c.s = nextState + + if c.s == stateIncrease { + var target float64 + if c.canIncreaseMultiplicatively(float64(deliveredRate)) { + window := ts.Sub(c.lastUpdate) + target = c.multiplicativeIncrease(float64(c.rate), window) + } else { + bitsPerFrame := float64(c.rate) / 30.0 + packetsPerFrame := math.Ceil(bitsPerFrame / (1200 * 8)) + expectedPacketSizeBits := bitsPerFrame / packetsPerFrame + target = c.additiveIncrease(float64(c.rate), int(expectedPacketSizeBits), rtt) + } + c.rate = int(max(min(target, 1.5*float64(deliveredRate)), float64(c.rate))) + } + + if c.s == stateDecrease { + c.rate = int(c.decreaseFactor * float64(deliveredRate)) + c.lastDecrease.update(float64(c.rate)) + } + + c.lastUpdate = ts + + return c.rate +} + +func (c *rateController) canIncreaseMultiplicatively(deliveredRate float64) bool { + if c.lastDecrease.average == 0 { + return true + } + stdDev := math.Sqrt(c.lastDecrease.variance) + lower := c.lastDecrease.average - 3*stdDev + upper := c.lastDecrease.average + 3*stdDev + return deliveredRate < lower || deliveredRate > upper +} + +func (c *rateController) multiplicativeIncrease(rate float64, window time.Duration) float64 { + exponent := min(window.Seconds(), 1.0) + eta := math.Pow(1.08, exponent) + target := eta * rate + return target +} + +func (c *rateController) additiveIncrease(rate float64, expectedPacketSizeBits int, window time.Duration) float64 { + alpha := 0.5 * min(window.Seconds(), 1.0) + target := rate + max(1000, alpha*float64(expectedPacketSizeBits)) + return target +} diff --git a/pkg/bwe/rate_controller_test.go b/pkg/bwe/rate_controller_test.go new file mode 100644 index 00000000..7f647dc9 --- /dev/null +++ b/pkg/bwe/rate_controller_test.go @@ -0,0 +1,143 @@ +package bwe + +import ( + "testing" + "time" + + "github.com/stretchr/testify/assert" +) + +func TestRateController(t *testing.T) { + cases := []struct { + name string + rc rateController + ts time.Time + u usage + delivered int + rtt time.Duration + expectedRate int + }{ + { + name: "zero", + rc: rateController{ + s: 0, + rate: 0, + decreaseFactor: 0, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{}, + }, + ts: time.Time{}, + u: 0, + delivered: 0, + rtt: 0, + expectedRate: 0, + }, + { + name: "multiplicativeIncrease", + rc: rateController{ + s: stateIncrease, + rate: 100, + decreaseFactor: 0.9, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{}, + }, + ts: time.Time{}.Add(time.Second), + u: usageNormal, + delivered: 100, + rtt: 0, + expectedRate: 108, + }, + { + name: "minimumAdditiveIncrease", + rc: rateController{ + s: stateIncrease, + rate: 100_000, + decreaseFactor: 0.9, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{ + average: 100_000, + }, + }, + ts: time.Time{}.Add(time.Second), + u: usageNormal, + delivered: 100_000, + rtt: 20 * time.Millisecond, + expectedRate: 101_000, + }, + { + name: "additiveIncrease", + rc: rateController{ + s: stateIncrease, + rate: 1_000_000, + decreaseFactor: 0.9, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{ + average: 1_000_000, + }, + }, + ts: time.Time{}.Add(time.Second), + u: usageNormal, + delivered: 1_000_000, + rtt: 2000 * time.Millisecond, + expectedRate: 1_004166, + }, + { + name: "minimumAdditiveIncreaseAppLimited", + rc: rateController{ + s: stateIncrease, + rate: 100_000, + decreaseFactor: 0.9, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{ + average: 100_000, + }, + }, + ts: time.Time{}.Add(time.Second), + u: usageNormal, + delivered: 50_000, + rtt: 20 * time.Millisecond, + expectedRate: 100_000, + }, + { + name: "additiveIncreaseAppLimited", + rc: rateController{ + s: stateIncrease, + rate: 1_000_000, + decreaseFactor: 0.9, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{ + average: 1_000_000, + }, + }, + ts: time.Time{}.Add(time.Second), + u: usageNormal, + delivered: 100_000, + rtt: 2000 * time.Millisecond, + expectedRate: 1_000_000, + }, + { + name: "decrease", + rc: rateController{ + s: stateDecrease, + rate: 1_000_000, + decreaseFactor: 0.9, + lastUpdate: time.Time{}, + lastDecrease: &exponentialMovingAverage{ + average: 1_000_000, + }, + }, + ts: time.Time{}.Add(time.Second), + u: usageOver, + delivered: 1_000_000, + rtt: 2000 * time.Millisecond, + expectedRate: 900_000, + }, + } + + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + res := tc.rc.update(tc.ts, tc.u, tc.delivered, tc.rtt) + assert.Equal(t, tc.expectedRate, res) + }) + } +} diff --git a/pkg/bwe/rtt.go b/pkg/bwe/rtt.go new file mode 100644 index 00000000..ad448f81 --- /dev/null +++ b/pkg/bwe/rtt.go @@ -0,0 +1,8 @@ +package bwe + +import "time" + +func MeasureRTT(reportSent, reportReceived, latestAckedSent, latestAckedArrival time.Time) time.Duration { + pendingTime := reportSent.Sub(latestAckedArrival) + return reportReceived.Sub(latestAckedSent) - pendingTime +} diff --git a/pkg/bwe/send_side_bwe.go b/pkg/bwe/send_side_bwe.go new file mode 100644 index 00000000..eac3d682 --- /dev/null +++ b/pkg/bwe/send_side_bwe.go @@ -0,0 +1,46 @@ +package bwe + +import ( + "log" + "time" +) + +type SendSideController struct { + dre *deliveryRateEstimator + lbc *LossRateController + drc *DelayRateController + rate int +} + +func NewSendSideController(initialRate, minRate, maxRate int) *SendSideController { + return &SendSideController{ + dre: newDeliveryRateEstimator(time.Second), + lbc: NewLossRateController(initialRate, minRate, maxRate), + drc: NewDelayRateController(initialRate), + } +} + +func (c *SendSideController) OnAcks(arrival time.Time, rtt time.Duration, acks []Acknowledgment) int { + if len(acks) == 0 { + return c.rate + } + + for _, ack := range acks { + if ack.Arrived { + c.lbc.OnPacketAcked() + if !ack.Arrival.IsZero() { + c.dre.OnPacketAcked(ack.Arrival, int(ack.Size)) + c.drc.OnPacketAcked(ack) + } + } else { + c.lbc.OnPacketLost() + } + } + + delivered := c.dre.GetRate() + lossTarget := c.lbc.Update(delivered) + delayTarget := c.drc.Update(arrival, delivered, rtt) + c.rate = min(lossTarget, delayTarget) + log.Printf("rtt=%v, delivered=%v, lossTarget=%v, delayTarget=%v, target=%v", rtt.Nanoseconds(), delivered, lossTarget, delayTarget, c.rate) + return c.rate +} diff --git a/pkg/bwe/state.go b/pkg/bwe/state.go new file mode 100644 index 00000000..167a1f64 --- /dev/null +++ b/pkg/bwe/state.go @@ -0,0 +1,59 @@ +package bwe + +import "fmt" + +type state int + +const ( + stateDecrease state = -1 + stateHold state = 0 + stateIncrease state = 1 +) + +func (s state) transition(u usage) state { + switch s { + case stateHold: + switch u { + case usageOver: + return stateDecrease + case usageNormal: + return stateIncrease + case usageUnder: + return stateHold + } + + case stateIncrease: + switch u { + case usageOver: + return stateDecrease + case usageNormal: + return stateIncrease + case usageUnder: + return stateHold + } + + case stateDecrease: + switch u { + case usageOver: + return stateDecrease + case usageNormal: + return stateHold + case usageUnder: + return stateHold + } + } + return stateIncrease +} + +func (s state) String() string { + switch s { + case stateIncrease: + return "increase" + case stateDecrease: + return "decrease" + case stateHold: + return "hold" + default: + return fmt.Sprintf("invalid state: %d", s) + } +} diff --git a/pkg/bwe/state_test.go b/pkg/bwe/state_test.go new file mode 100644 index 00000000..ecc8d1a0 --- /dev/null +++ b/pkg/bwe/state_test.go @@ -0,0 +1,27 @@ +package bwe + +import ( + "testing" + + "github.com/stretchr/testify/assert" +) + +func TestState(t *testing.T) { + t.Run("hold", func(t *testing.T) { + assert.Equal(t, stateDecrease, stateHold.transition(usageOver)) + assert.Equal(t, stateIncrease, stateHold.transition(usageNormal)) + assert.Equal(t, stateHold, stateHold.transition(usageUnder)) + }) + + t.Run("increase", func(t *testing.T) { + assert.Equal(t, stateDecrease, stateIncrease.transition(usageOver)) + assert.Equal(t, stateIncrease, stateIncrease.transition(usageNormal)) + assert.Equal(t, stateHold, stateIncrease.transition(usageUnder)) + }) + + t.Run("decrease", func(t *testing.T) { + assert.Equal(t, stateDecrease, stateDecrease.transition(usageOver)) + assert.Equal(t, stateHold, stateDecrease.transition(usageNormal)) + assert.Equal(t, stateHold, stateDecrease.transition(usageUnder)) + }) +} diff --git a/pkg/bwe/usage.go b/pkg/bwe/usage.go new file mode 100644 index 00000000..7d0a0b48 --- /dev/null +++ b/pkg/bwe/usage.go @@ -0,0 +1,24 @@ +package bwe + +import "fmt" + +type usage int + +const ( + usageUnder usage = -1 + usageNormal usage = 0 + usageOver usage = 1 +) + +func (u usage) String() string { + switch u { + case usageOver: + return "overuse" + case usageUnder: + return "underuse" + case usageNormal: + return "normal" + default: + return fmt.Sprintf("invalid usage: %d", u) + } +}