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#include "stdafx.h"
#include "net_acks.h"
#include <util/datetime/cputimer.h>
#include <atomic>
namespace NNetliba {
const float RTT_AVERAGE_OVER = 15;
float TCongestionControl::StartWindowSize = 3;
float TCongestionControl::MaxPacketRate = 0; // unlimited
bool UseTOSforAcks = false; //true;//
void EnableUseTOSforAcks(bool enable) {
UseTOSforAcks = enable;
}
float CONG_CTRL_CHANNEL_INFLATE = 1;
void SetCongCtrlChannelInflate(float inflate) {
CONG_CTRL_CHANNEL_INFLATE = inflate;
}
//////////////////////////////////////////////////////////////////////////
TPingTracker::TPingTracker()
: AvrgRTT(CONG_CTRL_INITIAL_RTT)
, AvrgRTT2(CONG_CTRL_INITIAL_RTT * CONG_CTRL_INITIAL_RTT)
, RTTCount(0)
{
}
void TPingTracker::RegisterRTT(float rtt) {
Y_ASSERT(rtt > 0);
float keep = RTTCount / (RTTCount + 1);
AvrgRTT *= keep;
AvrgRTT += (1 - keep) * rtt;
AvrgRTT2 *= keep;
AvrgRTT2 += (1 - keep) * Sqr(rtt);
RTTCount = Min(RTTCount + 1, RTT_AVERAGE_OVER);
//static int n;
//if ((++n % 1024) == 0)
// printf("Average RTT = %g (sko = %g)\n", GetRTT() * 1000, GetRTTSKO() * 1000);
}
void TPingTracker::IncreaseRTT() {
const float F_RTT_DECAY_RATE = 1.1f;
AvrgRTT *= F_RTT_DECAY_RATE;
AvrgRTT2 *= Sqr(F_RTT_DECAY_RATE);
}
//////////////////////////////////////////////////////////////////////////
void TAckTracker::Resend() {
CurrentPacket = 0;
for (TPacketHash::const_iterator i = PacketsInFly.begin(); i != PacketsInFly.end(); ++i)
Congestion->Failure(); // not actually correct but simplifies logic a lot
PacketsInFly.clear();
DroppedPackets.clear();
ResendQueue.clear();
for (size_t i = 0; i < AckReceived.size(); ++i)
AckReceived[i] = false;
}
int TAckTracker::SelectPacket() {
if (!ResendQueue.empty()) {
int res = ResendQueue.back();
ResendQueue.pop_back();
//printf("resending packet %d\n", res);
return res;
}
if (CurrentPacket == PacketCount) {
return -1;
}
return CurrentPacket++;
}
TAckTracker::~TAckTracker() {
for (TPacketHash::const_iterator i = PacketsInFly.begin(); i != PacketsInFly.end(); ++i)
Congestion->Failure();
// object will be incorrect state after this (failed packets are not added to resend queue), but who cares
}
int TAckTracker::GetPacketToSend(float deltaT) {
int res = SelectPacket();
if (res == -1) {
// needed to count time even if we don't have anything to send
Congestion->HasTriedToSend();
return res;
}
Congestion->LaunchPacket();
PacketsInFly[res] = -deltaT; // deltaT is time since last Step(), so for the timing to be correct we should subtract it
return res;
}
// called on SendTo() failure
void TAckTracker::AddToResend(int pkt) {
//printf("AddToResend(%d)\n", pkt);
TPacketHash::iterator i = PacketsInFly.find(pkt);
if (i != PacketsInFly.end()) {
PacketsInFly.erase(i);
Congestion->FailureOnSend();
ResendQueue.push_back(pkt);
} else
Y_ASSERT(0);
}
void TAckTracker::Ack(int pkt, float deltaT, bool updateRTT) {
Y_ASSERT(pkt >= 0 && pkt < PacketCount);
if (AckReceived[pkt])
return;
AckReceived[pkt] = true;
//printf("Ack received for %d\n", pkt);
TPacketHash::iterator i = PacketsInFly.find(pkt);
if (i == PacketsInFly.end()) {
for (size_t k = 0; k < ResendQueue.size(); ++k) {
if (ResendQueue[k] == pkt) {
ResendQueue[k] = ResendQueue.back();
ResendQueue.pop_back();
break;
}
}
TPacketHash::iterator z = DroppedPackets.find(pkt);
if (z != DroppedPackets.end()) {
// late packet arrived
if (updateRTT) {
float ping = z->second + deltaT;
Congestion->RegisterRTT(ping);
}
DroppedPackets.erase(z);
} else {
// Y_ASSERT(0); // ack on nonsent packet, possible in resend scenario
}
return;
}
if (updateRTT) {
float ping = i->second + deltaT;
//printf("Register RTT %g\n", ping * 1000);
Congestion->RegisterRTT(ping);
}
PacketsInFly.erase(i);
Congestion->Success();
}
void TAckTracker::AckAll() {
for (TPacketHash::const_iterator i = PacketsInFly.begin(); i != PacketsInFly.end(); ++i) {
int pkt = i->first;
AckReceived[pkt] = true;
Congestion->Success();
}
PacketsInFly.clear();
}
void TAckTracker::Step(float deltaT) {
float timeoutVal = Congestion->GetTimeout();
//static int n;
//if ((++n % 1024) == 0)
// printf("timeout = %g, window = %g, fail_rate %g, pkt_rate = %g\n", timeoutVal * 1000, Congestion->GetWindow(), Congestion->GetFailRate(), (1 - Congestion->GetFailRate()) * Congestion->GetWindow() / Congestion->GetRTT());
TimeToNextPacketTimeout = 1000;
// для окон меньше единицы мы кидаем рандом один раз за RTT на то, можно ли пускать пакет
// поэтому можно ждать максимум RTT, после этого надо кинуть новый random
if (Congestion->GetWindow() < 1)
TimeToNextPacketTimeout = Congestion->GetRTT();
for (auto& droppedPacket : DroppedPackets) {
float& t = droppedPacket.second;
t += deltaT;
}
for (TPacketHash::iterator i = PacketsInFly.begin(); i != PacketsInFly.end();) {
float& t = i->second;
t += deltaT;
if (t > timeoutVal) {
//printf("packet %d timed out (timeout = %g)\n", i->first, timeoutVal);
ResendQueue.push_back(i->first);
DroppedPackets[i->first] = i->second;
TPacketHash::iterator k = i++;
PacketsInFly.erase(k);
Congestion->Failure();
} else {
TimeToNextPacketTimeout = Min(TimeToNextPacketTimeout, timeoutVal - t);
++i;
}
}
}
static std::atomic<ui32> netAckRndVal = (ui32)GetCycleCount();
ui32 NetAckRnd() {
const auto nextNetAckRndVal = static_cast<ui32>(((ui64)netAckRndVal.load(std::memory_order_acquire) * 279470273) % 4294967291);
netAckRndVal.store(nextNetAckRndVal, std::memory_order_release);
return nextNetAckRndVal;
}
}
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