lsquic_pacer.c revision 90fe3b25
1229fce07SDmitri Tikhonov/* Copyright (c) 2017 - 2019 LiteSpeed Technologies Inc.  See LICENSE. */
250aadb33SDmitri Tikhonov#include <assert.h>
350aadb33SDmitri Tikhonov#include <inttypes.h>
450aadb33SDmitri Tikhonov#include <stdint.h>
550aadb33SDmitri Tikhonov#include <string.h>
6461e84d8SAmol Deshpande#ifdef WIN32
7461e84d8SAmol Deshpande#include <vc_compat.h>
8461e84d8SAmol Deshpande#endif
950aadb33SDmitri Tikhonov
1050aadb33SDmitri Tikhonov#include "lsquic_types.h"
1150aadb33SDmitri Tikhonov#include "lsquic_int_types.h"
1250aadb33SDmitri Tikhonov#include "lsquic_pacer.h"
1350aadb33SDmitri Tikhonov#include "lsquic_packet_common.h"
1450aadb33SDmitri Tikhonov#include "lsquic_packet_out.h"
1550aadb33SDmitri Tikhonov#include "lsquic_util.h"
1650aadb33SDmitri Tikhonov
1750aadb33SDmitri Tikhonov#define LSQUIC_LOGGER_MODULE LSQLM_PACER
1850aadb33SDmitri Tikhonov#define LSQUIC_LOG_CONN_ID pacer->pa_cid
1950aadb33SDmitri Tikhonov#include "lsquic_logger.h"
2050aadb33SDmitri Tikhonov
2150aadb33SDmitri Tikhonov#ifndef MAX
2250aadb33SDmitri Tikhonov#   define MAX(a, b) ((a) > (b) ? (a) : (b))
2350aadb33SDmitri Tikhonov#endif
2450aadb33SDmitri Tikhonov
2550aadb33SDmitri Tikhonov
2650aadb33SDmitri Tikhonovvoid
276aba801dSDmitri Tikhonovpacer_init (struct pacer *pacer, lsquic_cid_t cid, unsigned clock_granularity)
2850aadb33SDmitri Tikhonov{
2950aadb33SDmitri Tikhonov    memset(pacer, 0, sizeof(*pacer));
3050aadb33SDmitri Tikhonov    pacer->pa_burst_tokens = 10;
3150aadb33SDmitri Tikhonov    pacer->pa_cid = cid;
326aba801dSDmitri Tikhonov    pacer->pa_clock_granularity = clock_granularity;
3350aadb33SDmitri Tikhonov}
3450aadb33SDmitri Tikhonov
3550aadb33SDmitri Tikhonov
3650aadb33SDmitri Tikhonovvoid
37bfc7bfd8SDmitri Tikhonovpacer_cleanup (struct pacer *pacer)
38bfc7bfd8SDmitri Tikhonov{
39bfc7bfd8SDmitri Tikhonov#ifndef NDEBUG
4090fe3b25SDmitri Tikhonov    LSQ_DEBUG("scheduled calls: %u", pacer->pa_stats.n_scheduled);
41bfc7bfd8SDmitri Tikhonov#endif
42bfc7bfd8SDmitri Tikhonov}
43bfc7bfd8SDmitri Tikhonov
44bfc7bfd8SDmitri Tikhonov
45bfc7bfd8SDmitri Tikhonovvoid
4650aadb33SDmitri Tikhonovpacer_packet_scheduled (struct pacer *pacer, unsigned n_in_flight,
4750aadb33SDmitri Tikhonov                            int in_recovery, tx_time_f tx_time, void *tx_ctx)
4850aadb33SDmitri Tikhonov{
4950aadb33SDmitri Tikhonov    lsquic_time_t delay, sched_time;
5050aadb33SDmitri Tikhonov    int app_limited, making_up;
5150aadb33SDmitri Tikhonov
52bfc7bfd8SDmitri Tikhonov#ifndef NDEBUG
53bfc7bfd8SDmitri Tikhonov    ++pacer->pa_stats.n_scheduled;
54bfc7bfd8SDmitri Tikhonov#endif
55bfc7bfd8SDmitri Tikhonov
5650aadb33SDmitri Tikhonov    if (n_in_flight == 0 && !in_recovery)
5750aadb33SDmitri Tikhonov    {
5850aadb33SDmitri Tikhonov        pacer->pa_burst_tokens = 10;
5950aadb33SDmitri Tikhonov        LSQ_DEBUG("%s: replenish tokens: %u", __func__, pacer->pa_burst_tokens);
6050aadb33SDmitri Tikhonov    }
6150aadb33SDmitri Tikhonov
6250aadb33SDmitri Tikhonov    if (pacer->pa_burst_tokens > 0)
6350aadb33SDmitri Tikhonov    {
6450aadb33SDmitri Tikhonov        --pacer->pa_burst_tokens;
6550aadb33SDmitri Tikhonov        pacer->pa_flags &= ~PA_LAST_SCHED_DELAYED;
6650aadb33SDmitri Tikhonov        pacer->pa_next_sched = 0;
6750aadb33SDmitri Tikhonov        pacer->pa_last_delayed = 0;
6850aadb33SDmitri Tikhonov        LSQ_DEBUG("%s: tokens: %u", __func__, pacer->pa_burst_tokens);
6950aadb33SDmitri Tikhonov        return;
7050aadb33SDmitri Tikhonov    }
7150aadb33SDmitri Tikhonov
7250aadb33SDmitri Tikhonov    sched_time = pacer->pa_now;
7350aadb33SDmitri Tikhonov    delay = tx_time(tx_ctx);
7450aadb33SDmitri Tikhonov    if (pacer->pa_flags & PA_LAST_SCHED_DELAYED)
7550aadb33SDmitri Tikhonov    {
7650aadb33SDmitri Tikhonov        pacer->pa_next_sched += delay;
7750aadb33SDmitri Tikhonov        app_limited = pacer->pa_last_delayed != 0
7850aadb33SDmitri Tikhonov            && pacer->pa_last_delayed + delay <= sched_time;
7950aadb33SDmitri Tikhonov        making_up = pacer->pa_next_sched <= sched_time;
8050aadb33SDmitri Tikhonov        LSQ_DEBUG("making up: %d; app limited; %d", making_up, app_limited);
8150aadb33SDmitri Tikhonov        if (making_up && !app_limited)
8250aadb33SDmitri Tikhonov            pacer->pa_last_delayed = sched_time;
8350aadb33SDmitri Tikhonov        else
8450aadb33SDmitri Tikhonov        {
8550aadb33SDmitri Tikhonov            pacer->pa_flags &= ~PA_LAST_SCHED_DELAYED;
8650aadb33SDmitri Tikhonov            pacer->pa_last_delayed = 0;
8750aadb33SDmitri Tikhonov        }
8850aadb33SDmitri Tikhonov    }
8950aadb33SDmitri Tikhonov    else
9050aadb33SDmitri Tikhonov        pacer->pa_next_sched = MAX(pacer->pa_next_sched + delay,
9150aadb33SDmitri Tikhonov                                                    sched_time + delay);
9250aadb33SDmitri Tikhonov    LSQ_DEBUG("next_sched is set to %"PRIu64" usec from now",
9350aadb33SDmitri Tikhonov                                pacer->pa_next_sched - lsquic_time_now());
9450aadb33SDmitri Tikhonov}
9550aadb33SDmitri Tikhonov
9650aadb33SDmitri Tikhonov
9750aadb33SDmitri Tikhonovvoid
9850aadb33SDmitri Tikhonovpacer_loss_event (struct pacer *pacer)
9950aadb33SDmitri Tikhonov{
10050aadb33SDmitri Tikhonov    pacer->pa_burst_tokens = 0;
10150aadb33SDmitri Tikhonov    LSQ_DEBUG("%s: tokens: %u", __func__, pacer->pa_burst_tokens);
10250aadb33SDmitri Tikhonov}
10350aadb33SDmitri Tikhonov
10450aadb33SDmitri Tikhonov
10550aadb33SDmitri Tikhonovint
10650aadb33SDmitri Tikhonovpacer_can_schedule (struct pacer *pacer, unsigned n_in_flight)
10750aadb33SDmitri Tikhonov{
10850aadb33SDmitri Tikhonov    int can;
10950aadb33SDmitri Tikhonov
11050aadb33SDmitri Tikhonov    if (pacer->pa_burst_tokens > 0 || n_in_flight == 0)
11150aadb33SDmitri Tikhonov        can = 1;
1126aba801dSDmitri Tikhonov    else if (pacer->pa_next_sched > pacer->pa_now + pacer->pa_clock_granularity)
11350aadb33SDmitri Tikhonov    {
11450aadb33SDmitri Tikhonov        pacer->pa_flags |= PA_LAST_SCHED_DELAYED;
11550aadb33SDmitri Tikhonov        can = 0;
11650aadb33SDmitri Tikhonov    }
11750aadb33SDmitri Tikhonov    else
11850aadb33SDmitri Tikhonov        can = 1;
11950aadb33SDmitri Tikhonov
12050aadb33SDmitri Tikhonov    LSQ_DEBUG("%s: %d", __func__, can);
12150aadb33SDmitri Tikhonov    return can;
12250aadb33SDmitri Tikhonov}
12350aadb33SDmitri Tikhonov
12450aadb33SDmitri Tikhonov
12550aadb33SDmitri Tikhonovvoid
12650aadb33SDmitri Tikhonovpacer_tick (struct pacer *pacer, lsquic_time_t now)
12750aadb33SDmitri Tikhonov{
128bdba46fdSDmitri Tikhonov    assert(now >= pacer->pa_now);
12950aadb33SDmitri Tikhonov    pacer->pa_now = now;
13050aadb33SDmitri Tikhonov}
131