Re^2: $SIG{'ALRM'} on FreeBSD

Well, i thought the mistake is in my approach of usage of alrm signal, that's why i pasted only part where i used it. Sorry :) In fact i can't simulate that situation myself. But it happend on 3 servers already (all under freebsd) and not even on 1 from 4 under Linux.

Maybe you can suggest me another way of usage of timeout-ed operations? Means when need to limit time of execution of some subs. And limit for time smaller then second.

p.s. my "d" sub :)

sub time_stamp {
    my $time = shift;
    $time = time() if ! defined $time;
    my ($sec, $min, $hour, $mday, $mon, $year) = localtime($time);
    return sprintf("%02d:%02d:%02d %02d/%02d/%04d", $hour,
      $min, $sec, $mday, $mon+1, $year+1900);
}
sub d {
    print "[".time_stamp()."] ".(caller(0))[0].", ";
    print shift;
    print "\n";
}
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Re: $SIG{'ALRM'} on FreeBSD by jonadab (Parson) on Feb 24, 2006 at 15:48 UTC
After some experimentation, I have concluded that on my system the resolution of `select undef,undef,undef,$fractionalsecond` goes down to something on the order of 1/300 of a second, give or take. This is an estimate, and I haven't done proper benchmarks, and YMMV. `perl -e ' my $times = 5000; print "Starting: " . localtime() . "\n"; for (1..$times) { select undef,undef,undef,1/$times; } print "Done: " . localtime() . "\n"; ' Starting: Fri Feb 24 10:54:56 2006 Done: Fri Feb 24 10:55:06 2006` [download] About ten seconds to do 5000 iterations, would lead me to say 500 iterations per second would be the limit (on this system), but if I set $times to 300 it takes a full second or slightly more, so there's some overhead making the calculation imprecise. HTH.HAND.	[reply] [d/l] [select]

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Re: $SIG{'ALRM'} on FreeBSD
by jonadab (Parson) on Feb 24, 2006 at 15:48 UTC

After some experimentation, I have concluded that on my system the resolution of select undef,undef,undef,$fractionalsecond goes down to something on the order of 1/300 of a second, give or take. This is an estimate, and I haven't done proper benchmarks, and YMMV.

 perl -e '
my $times = 5000; print "Starting: " . localtime() . "\n";
for (1..$times) {
   select undef,undef,undef,1/$times;
}
print "Done: " . localtime() . "\n";
'
Starting: Fri Feb 24 10:54:56 2006
Done: Fri Feb 24 10:55:06 2006
[download]

About ten seconds to do 5000 iterations, would lead me to say 500 iterations per second would be the limit (on this system), but if I set $times to 300 it takes a full second or slightly more, so there's some overhead making the calculation imprecise. HTH.HAND.

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