It seems the problem can be solved by using POSIX exit.
(http://perldoc.perl.org/functions/exit.html )
Thanks to Chris who is in our IT department for pointing me to this. I
should have read it more carefully!
" The exit() function does not always exit immediately. It calls any
defined END routines first, but these END routines may not themselves
abort the exit. Likewise any object destructors that need to be called
are called before the real exit. If this is a problem, you can call
POSIX:_exit($status) to avoid END and destructor processing."
Thanks all!
-----Original Message-----
From: TAO, NENGBING [AG/1005]
Sent: Saturday, April 02, 2011 11:07 AM
To: 'beginners-digest-h...@perl.org'; beginners@perl.org
Subject: Excessive wait time after fork
Hi,
I noticed that after fork, the wait time is excessive (my other
test waited for hours). Is this a known problem, how to get around it?
This happens with ForkManager module also.
Any pointers on what's going on is appreciated!
Bob
########code########
#!/usr/bin/env perl
my @in = @ARGV;
my $num = scalar @in;
my @children;
for (my $i = 0; $i < $num; $i++) {
my $pid = fork();
if ($pid) { # parent
push @children, $pid;
print "parent $pid ", scalar localtime(),"\n";
} elsif ($pid == 0) { # child
print "child $i BEFORE sub call : ", scalar localtime(),"\n";
#sub
my $ref=longP($in[$i]);
print "child $i AFTER sub call :", scalar localtime()," numKeys:",
scalar keys %{$ref},"\n";
#sleep $in[$i];
exit;
} else {
print STDERR "couldn't fork\n";
}
}
print "before WAIT : ", scalar localtime(),"\n";
foreach my $child (@children) {
waitpid($child, 0);
print "Child $child done at ", scalar localtime(),"\n";
}
print "after WAIT : ", scalar localtime(),"\n";
print "Finished at ", scalar localtime(),"\n";
sub longP {
my ($i)=@_;
my %h=();
for my $j (0 .. $i * 1000000) {
$h{$j}=$j*100;
}
return \%h;
}
########command########
myTestOfFork 100 20 30 4 5 6 > O_myTestOfFork
########output########
parent 3052 Sat Apr 2 10:44:54 2011
parent 3053 Sat Apr 2 10:44:54 2011
parent 3054 Sat Apr 2 10:44:54 2011
parent 3055 Sat Apr 2 10:44:54 2011
parent 3056 Sat Apr 2 10:44:54 2011
child 3 BEFORE sub call : Sat Apr 2 10:44:54 2011
child 3 AFTER sub call :Sat Apr 2 10:45:01 2011 numKeys:4000001
child 4 BEFORE sub call : Sat Apr 2 10:44:54 2011
child 4 AFTER sub call :Sat Apr 2 10:45:04 2011 numKeys:5000001
child 5 BEFORE sub call : Sat Apr 2 10:44:54 2011
child 5 AFTER sub call :Sat Apr 2 10:45:06 2011 numKeys:6000001
child 1 BEFORE sub call : Sat Apr 2 10:44:54 2011
child 1 AFTER sub call :Sat Apr 2 10:45:41 2011 numKeys:20000001
child 2 BEFORE sub call : Sat Apr 2 10:44:54 2011
child 2 AFTER sub call :Sat Apr 2 10:45:56 2011 numKeys:30000001
child 0 BEFORE sub call : Sat Apr 2 10:44:54 2011
child 0 AFTER sub call :Sat Apr 2 10:48:45 2011 numKeys:100000001 #
all sub calls are finished at this time
parent 3057 Sat Apr 2 10:44:54 2011
before WAIT : Sat Apr 2 10:44:54 2011
Child 3052 done at Sat Apr 2 10:50:21 2011
Child 3053 done at Sat Apr 2 10:50:21 2011
Child 3054 done at Sat Apr 2 10:50:21 2011
Child 3055 done at Sat Apr 2 10:50:21 2011
Child 3056 done at Sat Apr 2 10:50:21 2011
Child 3057 done at Sat Apr 2 10:50:21 2011
after WAIT : Sat Apr 2 10:50:21 2011 #
why wait for additional 1:36 ?
Finished at Sat Apr 2 10:50:21 2011
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