snapshot of https://github.com/livekit/livekit.git @ 08c5433449c106943231037d0b892895f6e92d3b (2026-09-15)

pkg/sfu/bwe/remotebwe/probe_controller.go

@@ -0,0 +1,184 @@
+// Copyright 2023 LiveKit, 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.
+
+package remotebwe
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/livekit/livekit-server/pkg/sfu/bwe"
+	"github.com/livekit/livekit-server/pkg/sfu/ccutils"
+	"github.com/livekit/protocol/logger"
+	"github.com/livekit/protocol/utils/mono"
+)
+
+// ---------------------------------------------------------------------------
+
+type probeControllerState int
+
+const (
+	probeControllerStateNone probeControllerState = iota
+	probeControllerStateProbing
+	probeControllerStateHangover
+)
+
+func (p probeControllerState) String() string {
+	switch p {
+	case probeControllerStateNone:
+		return "NONE"
+	case probeControllerStateProbing:
+		return "PROBING"
+	case probeControllerStateHangover:
+		return "HANGOVER"
+	default:
+		return fmt.Sprintf("%d", int(p))
+	}
+}
+
+// ------------------------------------------------
+
+type ProbeControllerConfig struct {
+	ProbeRegulator ccutils.ProbeRegulatorConfig `yaml:"probe_regulator,omitempty"`
+
+	SettleWaitNumRTT uint32        `yaml:"settle_wait_num_rtt,omitempty"`
+	SettleWaitMin    time.Duration `yaml:"settle_wait_min,omitempty"`
+	SettleWaitMax    time.Duration `yaml:"settle_wait_max,omitempty"`
+}
+
+var (
+	DefaultProbeControllerConfig = ProbeControllerConfig{
+		ProbeRegulator: ccutils.DefaultProbeRegulatorConfig,
+
+		SettleWaitNumRTT: 5,
+		SettleWaitMin:    250 * time.Millisecond,
+		SettleWaitMax:    5 * time.Second,
+	}
+)
+
+// ---------------------------------------------------------------------------
+
+type probeControllerParams struct {
+	Config ProbeControllerConfig
+	Logger logger.Logger
+}
+
+type probeController struct {
+	params probeControllerParams
+
+	state           probeControllerState
+	stateSwitchedAt time.Time
+
+	pci ccutils.ProbeClusterInfo
+	rtt float64
+
+	*ccutils.ProbeRegulator
+}
+
+func newProbeController(params probeControllerParams) *probeController {
+	return &probeController{
+		params:          params,
+		state:           probeControllerStateNone,
+		stateSwitchedAt: mono.Now(),
+		pci:             ccutils.ProbeClusterInfoInvalid,
+		rtt:             bwe.DefaultRTT,
+		ProbeRegulator: ccutils.NewProbeRegulator(
+			ccutils.ProbeRegulatorParams{
+				Config: params.Config.ProbeRegulator,
+				Logger: params.Logger,
+			},
+		),
+	}
+}
+
+func (p *probeController) UpdateRTT(rtt float64) {
+	if rtt == 0 {
+		p.rtt = bwe.DefaultRTT
+	} else {
+		if p.rtt == 0 {
+			p.rtt = rtt
+		} else {
+			p.rtt = bwe.RTTSmoothingFactor*rtt + (1.0-bwe.RTTSmoothingFactor)*p.rtt
+		}
+	}
+}
+
+func (p *probeController) GetRTT() float64 {
+	return p.rtt
+}
+
+func (p *probeController) CanProbe() bool {
+	return p.state == probeControllerStateNone && p.ProbeRegulator.CanProbe()
+}
+
+func (p *probeController) IsInProbe() bool {
+	return p.state != probeControllerStateNone
+}
+
+func (p *probeController) ProbeClusterStarting(pci ccutils.ProbeClusterInfo) {
+	if p.state != probeControllerStateNone {
+		p.params.Logger.Warnw("unexpected probe controller state", nil, "state", p.state)
+	}
+
+	p.setState(probeControllerStateProbing)
+	p.pci = pci
+}
+
+func (p *probeController) ProbeClusterDone(pci ccutils.ProbeClusterInfo) {
+	if p.pci.Id != pci.Id {
+		return
+	}
+
+	p.pci.Result = pci.Result
+	p.setState(probeControllerStateHangover)
+}
+
+func (p *probeController) ProbeClusterIsGoalReached(estimate int64) bool {
+	if p.pci.Id == ccutils.ProbeClusterIdInvalid {
+		return false
+	}
+
+	return estimate > int64(p.pci.Goal.DesiredBps)
+}
+
+func (p *probeController) MaybeFinalizeProbe() (ccutils.ProbeClusterInfo, bool) {
+	if p.state != probeControllerStateHangover {
+		return ccutils.ProbeClusterInfoInvalid, false
+	}
+
+	settleWait := time.Duration(float64(p.params.Config.SettleWaitNumRTT) * p.rtt * float64(time.Second))
+	if settleWait < p.params.Config.SettleWaitMin {
+		settleWait = p.params.Config.SettleWaitMin
+	}
+	if settleWait > p.params.Config.SettleWaitMax {
+		settleWait = p.params.Config.SettleWaitMax
+	}
+	if time.Since(p.stateSwitchedAt) < settleWait {
+		return ccutils.ProbeClusterInfoInvalid, false
+	}
+
+	p.setState(probeControllerStateNone)
+	return p.pci, true
+}
+
+func (p *probeController) setState(state probeControllerState) {
+	if state == p.state {
+		return
+	}
+
+	p.state = state
+	p.stateSwitchedAt = mono.Now()
+}
+
+// ------------------------------------------------