Current File : //proc/self/root/usr/share/doc/libproc-processtable-perl/examples/pctcpu_example.pl
#!/usr/bin/perl
# created on 2018-02-12
use warnings;
use strict;
use v5.11;
use Proc::ProcessTable;
use Time::HiRes;
my @time_spans;
my %cpu_times;
my $ppt = Proc::ProcessTable->new;
my $start_time = [ Time::HiRes::gettimeofday() ];
my $poll_intervall = int( 2 * 1000 * 1000 ); # 2 sec
my $num_steps = 2;
local $| = 1;
my $cur_step = 0;
while (1) {
# current and old index of array.
# because of modulo, the idcs are rotated.
# the old index is always the oldest recorded entry
# this means the entry *after* the current index
#[ c o . . . ]
#[ . c o . . ]
#[ . . c o . ]
#[ . . . c o ]
#[ o . . . c ]
my $cur_idx = $cur_step % $num_steps;
my $old_idx = ( $cur_step + 1 ) % $num_steps;
# calc pct cpu per interval:
# we need seconds since
# https://stackoverflow.com/questions/16726779/how-do-i-get-the-total-cpu-usage-of-an-application-from-proc-pid-stat
my $t = Time::HiRes::tv_interval($start_time);
my $pt = $ppt->table;
my %active_procs = ();
for my $p (@$pt) {
# init process info if non-existent
my $pid = $p->pid;
$active_procs{$pid} = 1;
$cpu_times{$pid} //= [];
$cpu_times{$pid}[$cur_idx] = $p->time;
}
$time_spans[$cur_idx] = $t;
# clean the cputimes hash
my @killed_procs = grep { !$active_procs{$_} } keys %cpu_times ;
delete @cpu_times{@killed_procs};
my $ratio = 0;
# make sure the array is filled with cpu times
if ( $cur_step >= $num_steps ) {
# move cursor to top left of screen
print "\033[2J";
printf( "%-5s %s\n", "cpu", "pid");
# show cpu usage per process
for my $pid (keys %cpu_times) {
my $cpu_time = $cpu_times{$pid};
my $diff_cpu = ( $cpu_time->[$cur_idx] - ( $cpu_time->[$old_idx] // 0 ) ) / 1e6;
my $diff_start = ( $time_spans[$cur_idx] - $time_spans[$old_idx] );
$ratio = $diff_cpu / $diff_start if ( $diff_start > 0 );
# show only processes that have a usage > 1%
printf( "%5.1f %s\n", $ratio * 100, $pid ) if ( $ratio > 0.01 );
}
}
$cur_step++;
Time::HiRes::usleep($poll_intervall);
}
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