1 #include "print_latency.h"
13 using namespace std::chrono;
15 ReceivedTimestamps find_received_timestamp(const vector<RefCountedFrame> &input_frames)
17 unsigned num_cards = global_mixer->get_num_cards();
18 assert(input_frames.size() == num_cards * FRAME_HISTORY_LENGTH);
20 ReceivedTimestamps ts;
21 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
22 for (unsigned frame_index = 0; frame_index < FRAME_HISTORY_LENGTH; ++frame_index) {
23 const RefCountedFrame &input_frame = input_frames[card_index * FRAME_HISTORY_LENGTH + frame_index];
24 if (input_frame == nullptr ||
25 (frame_index > 0 && input_frame.get() == input_frames[card_index * FRAME_HISTORY_LENGTH + frame_index - 1].get())) {
26 ts.ts.push_back(steady_clock::time_point::min());
28 ts.ts.push_back(input_frame->received_timestamp);
35 void LatencyHistogram::init(const string &measuring_point)
37 unsigned num_cards = global_flags.num_cards; // The mixer might not be ready yet.
38 summaries.resize(num_cards * FRAME_HISTORY_LENGTH * 2);
39 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
40 char card_index_str[64];
41 snprintf(card_index_str, sizeof(card_index_str), "%u", card_index);
42 summaries[card_index].resize(FRAME_HISTORY_LENGTH);
43 for (unsigned frame_index = 0; frame_index < FRAME_HISTORY_LENGTH; ++frame_index) {
44 char frame_index_str[64];
45 snprintf(frame_index_str, sizeof(frame_index_str), "%u", frame_index);
47 vector<double> quantiles{0.01, 0.1, 0.25, 0.5, 0.75, 0.9, 0.99};
48 summaries[card_index][frame_index].reset(new Summary[2]);
49 summaries[card_index][frame_index][0].init(quantiles, 60.0);
50 summaries[card_index][frame_index][1].init(quantiles, 60.0);
51 global_metrics.add("latency_seconds",
52 {{ "measuring_point", measuring_point },
53 { "card", card_index_str },
54 { "frame_age", frame_index_str },
55 { "frame_type", "i/p" }},
56 &summaries[card_index][frame_index][0],
57 (frame_index == 0) ? Metrics::PRINT_ALWAYS : Metrics::PRINT_WHEN_NONEMPTY);
58 global_metrics.add("latency_seconds",
59 {{ "measuring_point", measuring_point },
60 { "card", card_index_str },
61 { "frame_age", frame_index_str },
62 { "frame_type", "b" }},
63 &summaries[card_index][frame_index][1],
64 Metrics::PRINT_WHEN_NONEMPTY);
69 void print_latency(const string &header, const ReceivedTimestamps &received_ts, bool is_b_frame, int *frameno, LatencyHistogram *histogram)
71 if (received_ts.ts.empty())
74 const steady_clock::time_point now = steady_clock::now();
76 unsigned num_cards = global_mixer->get_num_cards();
77 assert(received_ts.ts.size() == num_cards * FRAME_HISTORY_LENGTH);
78 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
79 for (unsigned frame_index = 0; frame_index < FRAME_HISTORY_LENGTH; ++frame_index) {
80 steady_clock::time_point ts = received_ts.ts[card_index * FRAME_HISTORY_LENGTH + frame_index];
81 if (ts == steady_clock::time_point::min()) {
84 duration<double> latency = now - ts;
85 histogram->summaries[card_index][frame_index][is_b_frame].count_event(latency.count());
89 // 101 is chosen so that it's prime, which is unlikely to get the same frame type every time.
90 if (global_flags.print_video_latency && (++*frameno % 101) == 0) {
91 // Find min and max timestamp of all input frames that have a timestamp.
92 steady_clock::time_point min_ts = steady_clock::time_point::max(), max_ts = steady_clock::time_point::min();
93 for (const auto &ts : received_ts.ts) {
94 if (ts > steady_clock::time_point::min()) {
95 min_ts = min(min_ts, ts);
96 max_ts = max(max_ts, ts);
99 duration<double> lowest_latency = now - max_ts;
100 duration<double> highest_latency = now - min_ts;
102 printf("%-60s %4.0f ms (lowest-latency input), %4.0f ms (highest-latency input)",
103 header.c_str(), 1e3 * lowest_latency.count(), 1e3 * highest_latency.count());
106 printf(" [on B-frame; potential extra latency]\n");