Files
mahimahi/scripts/mm-delay-graph
T
2022-02-25 09:40:25 +08:00

158 lines
3.9 KiB
Perl
Executable File

#!/usr/bin/env perl
use warnings;
use strict;
use POSIX;
sub usage
{
die qq{Usage: $0 [filename]\n};
}
if ( scalar @ARGV > 1 ) {
usage;
}
my $first_timestamp = undef;
my $last_timestamp = undef;
my $base_timestamp = undef;
my @delays;
my %signal_delay;
my $points;
LINE: while ( <> ) {
chomp;
if ( m{^# base timestamp: (\d+)} ) {
if ( defined $base_timestamp ) {
die "base timestamp multiply defined";
} else {
$base_timestamp = $1;
}
next LINE;
} elsif ( m{^#} ) {
next LINE;
}
# parse and validate line
my ( $timestamp, $event_type, $num_bytes, $delay ) = split /\s+/, $_;
if ( not defined $num_bytes ) {
die q{Format: timestamp event_type num_bytes [delay]};
}
if ( $timestamp !~ m{^\d+$} ) {
die qq{Invalid timestamp: $timestamp};
}
if ( $num_bytes !~ m{^\d+$} ) {
die qq{Invalid byte count: $num_bytes};
}
if ( not defined $base_timestamp ) {
die "logfile is missing base timestamp";
}
$timestamp -= $base_timestamp; # correct for startup time variation
if ( not defined $last_timestamp ) {
$last_timestamp = $first_timestamp = $timestamp;
}
$last_timestamp = max( $timestamp, $last_timestamp );
# process the event
if ( $event_type eq q{-} ) {
if ( not defined $delay ) {
die q{Departure format: timestamp - num_bytes delay};
}
push @delays, $delay;
$signal_delay{ $timestamp - $delay } = min( $delay, $signal_delay{ $timestamp - $delay } );
$points .= ($timestamp - $delay) / 1000.0 . " $delay\n";
}
}
sub max {
my $maxval = - POSIX::DBL_MAX;
for ( @_ ) {
next unless defined $_;
if ( $_ > $maxval ) {
$maxval = $_;
}
}
return $maxval;
}
sub min {
my $minval = POSIX::DBL_MAX;
for ( @_ ) {
next unless defined $_;
if ( $_ < $minval ) {
$minval = $_;
}
}
return $minval;
}
# calculate statistics
if ( scalar @delays == 0 ) {
die q{Must have at least one departure event};
}
@delays = sort { $a <=> $b } @delays;
my $pp95 = $delays[ 0.95 * scalar @delays ];
my $pp50 = $delays[ 0.5 * scalar @delays ];
# measure signal delay every millisecond
# = minimum time for a message created at time t to get to receiver
my @signal_delay_samples = sort { $a <=> $b } keys %signal_delay;
for ( my $ts = $signal_delay_samples[ -1 ]; $ts >= $signal_delay_samples[ 0 ]; $ts-- ) {
if ( not defined $signal_delay{ $ts } ) {
$signal_delay{ $ts } = $signal_delay{ $ts + 1 } + 1;
}
}
my $signal_delay_points;
for ( my $ts = $signal_delay_samples[ 0 ]; $ts <= $signal_delay_samples[ -1 ]; $ts++ ) {
$signal_delay_points .= $ts / 1000.0 . " " . $signal_delay{ $ts } . "\n";
}
my @signal_delays = sort { $a <=> $b } values %signal_delay;
my $pp95s = $signal_delays[ 0.95 * scalar @signal_delays ];
printf STDERR qq{95th percentile per-packet queueing delay: %.0f ms\n}, $pp95;
printf STDERR qq{95th percentile signal delay: %.0f ms\n}, $pp95s;
my $graph_max = $signal_delays[-1] * 1.2;
# make graph
open GNUPLOT, q{| gnuplot} or die;
my $lower_limit = min( 30, int $pp50 );
print GNUPLOT <<END;
set xlabel "time (s)"
set ylabel "delay (ms)
set logscale y
set yrange [$lower_limit:$graph_max]
set ytics add ($lower_limit)
set key center outside top horizontal
set terminal svg size 1024,560 fixed enhanced fname 'Arial' solid mouse standalone name "Delay"
set output "/dev/stdout"
END
printf GNUPLOT qq{plot [%f:%f] "-" using 1:2 title "Signal delay" with filledcurves above x1 lt 1 fs solid 0.4 noborder fc rgb "#0000ff", "-" using 1:2 title "Per-packet delay" with points lt 7 ps 0.15 lc rgb "#00ff0000", %f with lines lw 10 lc rgb "#800000ff" title "95th percentile signal delay (%.0f ms)", %f with lines lw 10 lc rgb "#80ff0000" title "95th percentile per-packet delay (%.0f ms)"\n}, $first_timestamp / 1000.0, $last_timestamp / 1000.0, $pp95s, $pp95s, $pp95, $pp95;
print GNUPLOT $signal_delay_points;
print GNUPLOT "e\n";
print GNUPLOT $points;
close GNUPLOT or die qq{$!};