Commit 67f15d71 authored by rna's avatar rna
Browse files

Refactor BBR to use maximum payload size.

parent a08fa1d6

prrt/proto/bbr.c

+20 −17
Original line number Diff line number Diff line
@@ -4,11 +4,10 @@ 
#include "receiver.h"

#include <math.h>





prrtByteCount_t BBR_Inflight(BBR* bbr, double gain)

{

    if (bbr->rtprop == Inf)

        return InitialCwnd; /* no valid RTT samples yet */

        return bbr->initial_cwnd; /* no valid RTT samples yet */

    uint32_t quanta = 0;

    uint32_t estimated_bdp = (uint32_t) round((((double)bbr->bw) * bbr->rtprop) / (1000 * 1000));

    return (uint32_t)(gain * estimated_bdp + quanta);
@@ -41,7 +40,7 @@ void BBR_CheckFullPipe(BBR* bbr, PrrtRateSample* rs) 
{

    if (bbr->filled_pipe || !bbr->round_start || rs->is_app_limited)

        return;  // no need to check for a full pipe now

    if (bbr->bw >= bbr->full_bw * 1.25) {  // BBR.BtlBw still growing?

    if (bbr->bw >= bbr->full_bw * PROBE_GAIN) {  // BBR.BtlBw still growing?

        bbr->full_bw = bbr->bw;    // record new baseline level

        bbr->full_bw_count = 0;

        return;
@@ -58,14 +57,16 @@ bool BBR_IsNextCyclePhase(BBR* bbr, prrtByteCount_t bytes_lost, prrtByteCount_t 
        return is_full_length;

    if (bbr->pacing_gain > 1)

        return is_full_length && (bytes_lost > 0 || prior_inflight >= BBR_Inflight(bbr, bbr->pacing_gain));

    return is_full_length || (prior_inflight <= BBR_Inflight(bbr, 1.0));

    bool is_max_length = (PrrtClock_get_current_time_us() - bbr->cycle_stamp) > 4 * bbr->rtprop;

    return is_max_length || (prior_inflight <= BBR_Inflight(bbr, 1.0));



}



void BBR_AdvanceCyclePhase(BBR* bbr)

{

    bbr->cycle_stamp = PrrtClock_get_current_time_us();

    bbr->cycle_index = (uint8_t )((bbr->cycle_index + 1) % BBRGainCycleLen);

    float pacing_gain_cycle[BBRGainCycleLen] = {1.25, 0.75, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0};

    float pacing_gain_cycle[BBRGainCycleLen] = {PROBE_GAIN, DRAIN_GAIN, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0};

    bbr->pacing_gain = pacing_gain_cycle[bbr->cycle_index];

    debug(DEBUG_BBR, "Advanced cycle with gain: %f", bbr->pacing_gain);

}
@@ -135,7 +136,7 @@ void BBR_HandleProbeRTT(BBR *bbr, PrrtPacketTracking *tracking) { 
    tracking->app_limited = (tracking->delivered + tracking->pipe) ? : 1;

    /* Ignore low rate samples during ProbeRTT: */

    prrtTimestamp_t now = PrrtClock_get_current_time_us();

    if (bbr->probe_rtt_done_stamp == 0 && tracking->pipe <= BBRMinPipeCwnd) {

    if (bbr->probe_rtt_done_stamp == 0 && tracking->pipe <= bbr->min_pipe_cwnd) {

        bbr->probe_rtt_done_stamp = now + ProbeRTTDuration;

        bbr->probe_rtt_round_done = false;

        bbr->next_round_delivered = tracking->delivered;
@@ -183,13 +184,13 @@ void BBR_UpdateTargetCwnd(BBR* bbr) 
void BBR_ModulateCwndForProbeRTT(BBR* bbr)

{

    if (bbr->state == PROBE_RTT)

        bbr->cwnd = MIN(bbr->cwnd, BBRMinPipeCwnd);

        bbr->cwnd = MIN(bbr->cwnd, bbr->min_pipe_cwnd);

}



void BBR_ModulateCwndForRecovery(BBR* bbr, prrtByteCount_t bytes_lost, prrtByteCount_t pipe, prrtByteCount_t delivered)

{

    if (bytes_lost > 0)

        bbr->cwnd = MAX(bbr->cwnd - bytes_lost, SMSS);

        bbr->cwnd = MAX(bbr->cwnd - bytes_lost, bbr->mps);

    if (bbr->packet_conservation)

        bbr->cwnd = MAX(bbr->cwnd, pipe + delivered);

}
@@ -202,9 +203,9 @@ void BBR_SetCwnd(BBR* bbr, PrrtPacketTracking* packetTracking) 
    if (!bbr->packet_conservation) {

        if (bbr->filled_pipe)

            bbr->cwnd = MIN(bbr->cwnd + packetTracking->delivered, bbr->target_cwnd);

        else if (bbr->cwnd < bbr->target_cwnd || packetTracking->delivered < InitialCwnd)

        else if (bbr->cwnd < bbr->target_cwnd || packetTracking->delivered < bbr->initial_cwnd)

            bbr->cwnd = bbr->cwnd + packetTracking->delivered;

        bbr->cwnd = MAX(bbr->cwnd, BBRMinPipeCwnd);

        bbr->cwnd = MAX(bbr->cwnd, bbr->min_pipe_cwnd);

    }

    BBR_ModulateCwndForProbeRTT(bbr);

    debug(DEBUG_BBR, "New cwnd: %u, State: %u", bbr->cwnd, bbr->state);
@@ -226,9 +227,9 @@ void BBR_SetPacingRate(BBR* bbr) 


void BBR_SetSendQuantum(BBR* bbr) {

    if(bbr->pacing_rate < 150000) { // 1.2Mbps = 0.15 MBps = 150000 Bps

        bbr->send_quantum = 1 * SMSS;

        bbr->send_quantum = 1 * bbr->mps;

    } else if (bbr->pacing_rate < 3000000) { // 24 Mbps = 20 * 1.2Mbps = 3000000

        bbr->send_quantum = 2 * SMSS;

        bbr->send_quantum = 2 * bbr->mps;

    } else {

        bbr->send_quantum = MIN((prrtByteCount_t) round((double) bbr->pacing_rate / 1000), 64000);

    }
@@ -270,7 +271,7 @@ void BBR_OnRTOLoss(BBR *bbr) { 
    if(!bbr->is_loss_recovery) {

        bbr->is_loss_recovery = true;

        bbr->prior_cwnd = BBR_SaveCwnd(bbr);

        bbr->cwnd = SMSS;

        bbr->cwnd = bbr->mps;

    }

    check(pthread_mutex_unlock(&bbr->lock) == 0, "Unlock failed.");

    return;
@@ -291,7 +292,7 @@ void BBR_OnLossExit(BBR *bbr) { 
    PERROR("BBR_OnACK failed.")

}



BBR* BBR_Init(void)

BBR* BBR_Init(prrtByteCount_t maximum_payload_size)

{

    BBR* bbr = calloc(1, sizeof(BBR));

    check_mem(bbr);
@@ -301,7 +302,9 @@ BBR* BBR_Init(void) 
    check(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) == EXIT_SUCCESS, "Setting type failed.");

    check(pthread_mutex_init(&bbr->lock, &attr) == 0, "lock init failed.");





    bbr->mps = maximum_payload_size;

    bbr->min_pipe_cwnd = 4 * maximum_payload_size;

    bbr->initial_cwnd = 4 * maximum_payload_size;

    bbr->has_seen_rtt = false;

    bbr->btlBwFilter = WindowedFilter_Init(true);

    bbr->rtprop = Inf;
@@ -310,7 +313,7 @@ BBR* BBR_Init(void) 
    bbr->probe_rtt_round_done = false;

    bbr->packet_conservation = false;

    bbr->prior_cwnd = 0;

    bbr->cwnd = InitialCwnd;

    bbr->cwnd = bbr->initial_cwnd;

    bbr->idle_restart = false;

    bbr->is_loss_recovery = false;
@@ -325,7 +328,7 @@ BBR* BBR_Init(void) 
    bbr->full_bw_count = 0;



    //Init pacing rate

    double nominal_bandwidth = InitialCwnd / (bbr->has_seen_rtt ? bbr->rtprop : 1000);

    double nominal_bandwidth = bbr->initial_cwnd / (bbr->has_seen_rtt ? bbr->rtprop : 1000);

    bbr->pacing_rate = bbr->pacing_gain * nominal_bandwidth;



    BBR_EnterStartup(bbr);

prrt/proto/bbr.h

+6 −4
Original line number Diff line number Diff line
@@ -10,12 +10,11 @@ 
#include "types/rateSample.h"

#include "../util/windowedFilter.h"



#define SMSS 1500

#define PROBE_GAIN 1.25

#define DRAIN_GAIN 0.75

#define RTpropFilterLen 10000000    //10s

#define BBRHighGain ((((float)2885) / 1000) + 1)

#define InitialCwnd (10 * SMSS)

#define BBRGainCycleLen 8

#define BBRMinPipeCwnd (4 * SMSS)

#define ProbeRTTDuration 200000 //200ms

#define Inf UINT32_MAX
@@ -29,6 +28,9 @@ enum bbr_state { 
typedef struct bbr {

    pthread_mutex_t lock;



    prrtByteCount_t mps;

    prrtByteCount_t min_pipe_cwnd;

    prrtByteCount_t initial_cwnd;

    prrtTimedelta_t rtprop;

    prrtTimestamp_t rtprop_stamp;

    prrtTimestamp_t probe_rtt_done_stamp;
@@ -73,7 +75,7 @@ typedef struct bbr { 
    WindowedFilter* btlBwFilter;

} BBR;



BBR* BBR_Init(void);

BBR* BBR_Init(prrtByteCount_t maximum_payload_size);

void BBR_OnACK(BBR* bbr, PrrtChannelStateInformation* csi, PrrtRateSample* rs, PrrtPacketTracking* packetTracking, prrtTimedelta_t rtt);

void BBR_OnSpuriousLoss(BBR *bbr, PrrtPacketTracking *tracking);

void BBR_OnRTOLoss(BBR *bbr);

prrt/proto/receiver.c

+2 −2
Original line number Diff line number Diff line
@@ -98,7 +98,7 @@ bool update_and_generate_rate_sample(PrrtReceiver *recv, prrtSequenceNumber_t se 
    return result;

}



PrrtReceiver *PrrtReceiver_create(const char *host, uint16_t port, prrtByteCount_t mss) {

PrrtReceiver *PrrtReceiver_create(const char *host, uint16_t port, prrtByteCount_t maximum_payload_size) {

    PrrtReceiver *recv = calloc(1, sizeof(PrrtReceiver));

    check_mem(recv);

    recv->host_name = strdup(host);
@@ -130,7 +130,7 @@ PrrtReceiver *PrrtReceiver_create(const char *host, uint16_t port, prrtByteCount 
    check(0 == getaddrinfo(host, portstr, &hints, &info), "getaddrinfo");



    recv->ai = info;

    recv->bbr = BBR_Init();

    recv->bbr = BBR_Init(maximum_payload_size);



    pthread_mutexattr_t attr;

    check(pthread_mutexattr_init(&attr) == EXIT_SUCCESS, "Mutex attr init failed.");

prrt/proto/receiver.h

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ typedef struct prrtReceiver { 
    PrrtPacketTracking *packetTracking;

} PrrtReceiver;



PrrtReceiver *PrrtReceiver_create(const char *host, uint16_t port, prrtByteCount_t mss);

PrrtReceiver *PrrtReceiver_create(const char *host, uint16_t port, prrtByteCount_t maximum_payload_size);



void PrrtReceiver_add_outstanding_packet_state(PrrtReceiver *recv, PrrtPacket *packet, prrtTimestamp_t sentTime);

prrtByteCount_t PrrtReceiver_get_pipe(PrrtReceiver *recv);