forked from quic-go/quic-go
278 lines
11 KiB
Go
278 lines
11 KiB
Go
package flowcontrol
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import (
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"time"
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"github.com/lucas-clemente/quic-go/congestion"
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"github.com/lucas-clemente/quic-go/internal/protocol"
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. "github.com/onsi/ginkgo"
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. "github.com/onsi/gomega"
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)
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var _ = Describe("Flow controller", func() {
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var controller *flowController
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BeforeEach(func() {
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controller = &flowController{}
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controller.rttStats = &congestion.RTTStats{}
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})
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Context("Constructor", func() {
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rttStats := &congestion.RTTStats{}
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It("sets the send and receive windows", func() {
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receiveWindow := protocol.ByteCount(2000)
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maxReceiveWindow := protocol.ByteCount(3000)
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sendWindow := protocol.ByteCount(4000)
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fc := newFlowController(5, true, receiveWindow, maxReceiveWindow, sendWindow, rttStats)
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Expect(fc.streamID).To(Equal(protocol.StreamID(5)))
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Expect(fc.receiveWindow).To(Equal(receiveWindow))
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Expect(fc.maxReceiveWindowIncrement).To(Equal(maxReceiveWindow))
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Expect(fc.sendWindow).To(Equal(sendWindow))
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})
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It("says if it contributes to connection-level flow control", func() {
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fc := newFlowController(1, false, protocol.MaxByteCount, protocol.MaxByteCount, protocol.MaxByteCount, rttStats)
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Expect(fc.ContributesToConnection()).To(BeFalse())
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fc = newFlowController(5, true, protocol.MaxByteCount, protocol.MaxByteCount, protocol.MaxByteCount, rttStats)
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Expect(fc.ContributesToConnection()).To(BeTrue())
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})
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})
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Context("send flow control", func() {
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It("adds bytes sent", func() {
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controller.bytesSent = 5
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controller.AddBytesSent(6)
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Expect(controller.bytesSent).To(Equal(protocol.ByteCount(5 + 6)))
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})
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It("gets the size of the remaining flow control window", func() {
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controller.bytesSent = 5
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controller.sendWindow = 12
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Expect(controller.SendWindowSize()).To(Equal(protocol.ByteCount(12 - 5)))
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})
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It("gets the offset of the flow control window", func() {
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controller.bytesSent = 5
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controller.sendWindow = 12
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Expect(controller.sendWindow).To(Equal(protocol.ByteCount(12)))
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})
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It("updates the size of the flow control window", func() {
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controller.bytesSent = 5
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updateSuccessful := controller.UpdateSendWindow(15)
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Expect(updateSuccessful).To(BeTrue())
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Expect(controller.sendWindow).To(Equal(protocol.ByteCount(15)))
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Expect(controller.SendWindowSize()).To(Equal(protocol.ByteCount(15 - 5)))
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})
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It("does not decrease the flow control window", func() {
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updateSuccessful := controller.UpdateSendWindow(20)
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Expect(updateSuccessful).To(BeTrue())
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Expect(controller.SendWindowSize()).To(Equal(protocol.ByteCount(20)))
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updateSuccessful = controller.UpdateSendWindow(10)
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Expect(updateSuccessful).To(BeFalse())
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Expect(controller.SendWindowSize()).To(Equal(protocol.ByteCount(20)))
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})
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})
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Context("receive flow control", func() {
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var receiveWindow protocol.ByteCount = 10000
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var receiveWindowIncrement protocol.ByteCount = 600
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BeforeEach(func() {
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controller.receiveWindow = receiveWindow
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controller.receiveWindowIncrement = receiveWindowIncrement
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})
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It("adds bytes read", func() {
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controller.bytesRead = 5
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controller.AddBytesRead(6)
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Expect(controller.bytesRead).To(Equal(protocol.ByteCount(5 + 6)))
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})
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It("triggers a window update when necessary", func() {
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controller.lastWindowUpdateTime = time.Now().Add(-time.Hour)
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readPosition := receiveWindow - receiveWindowIncrement/2 + 1
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controller.bytesRead = readPosition
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updateNecessary, _, offset := controller.MaybeUpdateWindow()
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Expect(updateNecessary).To(BeTrue())
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Expect(offset).To(Equal(readPosition + receiveWindowIncrement))
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Expect(controller.receiveWindow).To(Equal(readPosition + receiveWindowIncrement))
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Expect(controller.lastWindowUpdateTime).To(BeTemporally("~", time.Now(), 20*time.Millisecond))
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})
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It("doesn't trigger a window update when not necessary", func() {
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lastWindowUpdateTime := time.Now().Add(-time.Hour)
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controller.lastWindowUpdateTime = lastWindowUpdateTime
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readPosition := receiveWindow - receiveWindow/2 - 1
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controller.bytesRead = readPosition
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updateNecessary, _, _ := controller.MaybeUpdateWindow()
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Expect(updateNecessary).To(BeFalse())
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Expect(controller.lastWindowUpdateTime).To(Equal(lastWindowUpdateTime))
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})
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It("updates the highestReceived", func() {
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controller.highestReceived = 1337
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increment, err := controller.UpdateHighestReceived(1338)
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Expect(err).ToNot(HaveOccurred())
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Expect(increment).To(Equal(protocol.ByteCount(1338 - 1337)))
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Expect(controller.highestReceived).To(Equal(protocol.ByteCount(1338)))
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})
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It("does not decrease the highestReceived", func() {
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controller.highestReceived = 1337
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increment, err := controller.UpdateHighestReceived(1000)
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Expect(err).To(MatchError(ErrReceivedSmallerByteOffset))
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Expect(increment).To(BeZero())
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Expect(controller.highestReceived).To(Equal(protocol.ByteCount(1337)))
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})
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It("does not error when setting the same byte offset", func() {
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controller.highestReceived = 1337
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increment, err := controller.UpdateHighestReceived(1337)
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Expect(err).ToNot(HaveOccurred())
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Expect(increment).To(BeZero())
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})
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It("increases the highestReceived by a given increment", func() {
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controller.highestReceived = 1337
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controller.IncrementHighestReceived(123)
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Expect(controller.highestReceived).To(Equal(protocol.ByteCount(1337 + 123)))
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})
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It("detects a flow control violation", func() {
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controller.UpdateHighestReceived(receiveWindow + 1)
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Expect(controller.CheckFlowControlViolation()).To(BeTrue())
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})
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It("does not give a flow control violation when using the window completely", func() {
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controller.UpdateHighestReceived(receiveWindow)
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Expect(controller.CheckFlowControlViolation()).To(BeFalse())
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})
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Context("receive window increment auto-tuning", func() {
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var oldIncrement protocol.ByteCount
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BeforeEach(func() {
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oldIncrement = controller.receiveWindowIncrement
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controller.maxReceiveWindowIncrement = 3000
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})
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// update the congestion such that it returns a given value for the smoothed RTT
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setRtt := func(t time.Duration) {
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controller.rttStats.UpdateRTT(t, 0, time.Now())
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Expect(controller.rttStats.SmoothedRTT()).To(Equal(t)) // make sure it worked
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}
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It("doesn't increase the increment for a new stream", func() {
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(oldIncrement))
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})
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It("doesn't increase the increment when no RTT estimate is available", func() {
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setRtt(0)
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controller.lastWindowUpdateTime = time.Now()
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(oldIncrement))
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})
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It("increases the increment when the last WindowUpdate was sent less than two RTTs ago", func() {
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setRtt(20 * time.Millisecond)
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controller.lastWindowUpdateTime = time.Now().Add(-35 * time.Millisecond)
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(2 * oldIncrement))
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})
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It("doesn't increase the increase increment when the last WindowUpdate was sent more than two RTTs ago", func() {
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setRtt(20 * time.Millisecond)
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controller.lastWindowUpdateTime = time.Now().Add(-45 * time.Millisecond)
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(oldIncrement))
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})
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It("doesn't increase the increment to a value higher than the maxReceiveWindowIncrement", func() {
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setRtt(20 * time.Millisecond)
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controller.lastWindowUpdateTime = time.Now().Add(-35 * time.Millisecond)
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(2 * oldIncrement)) // 1200
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// because the lastWindowUpdateTime is updated by MaybeTriggerWindowUpdate(), we can just call maybeAdjustWindowIncrement() multiple times and get an increase of the increment every time
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(2 * 2 * oldIncrement)) // 2400
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(controller.maxReceiveWindowIncrement)) // 3000
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controller.maybeAdjustWindowIncrement()
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Expect(controller.receiveWindowIncrement).To(Equal(controller.maxReceiveWindowIncrement)) // 3000
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})
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It("returns the new increment when updating the window", func() {
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setRtt(20 * time.Millisecond)
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controller.AddBytesRead(9900) // receive window is 10000
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controller.lastWindowUpdateTime = time.Now().Add(-35 * time.Millisecond)
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necessary, newIncrement, offset := controller.MaybeUpdateWindow()
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Expect(necessary).To(BeTrue())
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Expect(newIncrement).To(Equal(2 * oldIncrement))
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Expect(controller.receiveWindowIncrement).To(Equal(newIncrement))
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Expect(offset).To(Equal(protocol.ByteCount(9900 + newIncrement)))
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})
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It("increases the increment sent in the first WindowUpdate, if data is read fast enough", func() {
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setRtt(20 * time.Millisecond)
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controller.AddBytesRead(9900)
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necessary, newIncrement, _ := controller.MaybeUpdateWindow()
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Expect(necessary).To(BeTrue())
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Expect(newIncrement).To(Equal(2 * oldIncrement))
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})
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It("doesn't increamse the increment sent in the first WindowUpdate, if data is read slowly", func() {
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setRtt(5 * time.Millisecond)
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controller.AddBytesRead(9900)
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time.Sleep(15 * time.Millisecond) // more than 2x RTT
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necessary, newIncrement, _ := controller.MaybeUpdateWindow()
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Expect(necessary).To(BeTrue())
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Expect(newIncrement).To(BeZero())
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})
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It("only returns the increment if it was increased", func() {
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setRtt(20 * time.Millisecond)
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controller.AddBytesRead(9900) // receive window is 10000
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controller.lastWindowUpdateTime = time.Now().Add(-45 * time.Millisecond)
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necessary, newIncrement, offset := controller.MaybeUpdateWindow()
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Expect(necessary).To(BeTrue())
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Expect(newIncrement).To(BeZero())
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Expect(controller.receiveWindowIncrement).To(Equal(oldIncrement))
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Expect(offset).To(Equal(protocol.ByteCount(9900 + oldIncrement)))
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})
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Context("setting the minimum increment", func() {
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It("sets the minimum window increment", func() {
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controller.EnsureMinimumWindowIncrement(1000)
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Expect(controller.receiveWindowIncrement).To(Equal(protocol.ByteCount(1000)))
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})
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It("doesn't reduce the window increment", func() {
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controller.EnsureMinimumWindowIncrement(1)
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Expect(controller.receiveWindowIncrement).To(Equal(oldIncrement))
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})
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It("doens't increase the increment beyong the maxReceiveWindowIncrement", func() {
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max := controller.maxReceiveWindowIncrement
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controller.EnsureMinimumWindowIncrement(2 * max)
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Expect(controller.receiveWindowIncrement).To(Equal(max))
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})
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It("doesn't auto-tune the window after the increment was increased", func() {
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setRtt(20 * time.Millisecond)
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controller.bytesRead = 9900 // receive window is 10000
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controller.lastWindowUpdateTime = time.Now().Add(-20 * time.Millisecond)
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controller.EnsureMinimumWindowIncrement(912)
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necessary, newIncrement, offset := controller.MaybeUpdateWindow()
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Expect(necessary).To(BeTrue())
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Expect(newIncrement).To(BeZero()) // no auto-tuning
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Expect(offset).To(Equal(protocol.ByteCount(9900 + 912)))
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})
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})
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})
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})
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})
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