measure_delay.py

# -*- coding: utf-8 -*-
# cfoch-tesis results
# Copyright (c) 2018 Fabian Orccon <cfoch.fabian@gmail.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this program; if not, write to the
# Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
import argparse
import numpy as np
import matplotlib.pyplot as plt
import os

DEFAULT_HEAD_REMOVE = 7
LATENCY_PATTERN = "time=(guint64)"
LATENCY_PATTERN_LEN = len(LATENCY_PATTERN)

parser = argparse.ArgumentParser()
parser.add_argument("-i", "--trace-file",
    help="The path to the output of the trace log.", required=True)
parser.add_argument("-H", "--head-remove",
    help="Ignore h last lines from the start of the trace file.",
    default=DEFAULT_HEAD_REMOVE, required=False)
parser.add_argument("-d", "--display",
    help="Sets whether to display or not a plot of the latency.",
    action="store_true", required=False)
args = parser.parse_args()

def plot_latency_data(data):
    plt.plot(data * 1e-9)
    plt.title("Latencia por Buffer")
    plt.ylabel("Latencia (segundos)")
    plt.xlabel("Buffer")
    plt.show()

def get_latency_from_log_string(log_str):
    lines = log_str.split("\n")
    lines = lines[args.head_remove:-1]
    data = []
    for line in lines:
        start = line.find(LATENCY_PATTERN) + LATENCY_PATTERN_LEN
        subline = line[start:]
        end = subline.find(",")
        latency_str = subline[:end]
        latency = int(latency_str)
        data.append(latency)
    return np.array(data)

with open(args.trace_file, "r") as f:
    log_str = f.read()
    latency_data = get_latency_from_log_string(log_str)
    print("Latency average: ", np.average(latency_data))
    if args.display:
        plot_latency_data(latency_data)