Perl的Parallel::ForkManager是用来管理进程创建的模块，据说它可以做到根据各个CPU当前的负载决定在哪颗CPU上fork进程。
| #!/usr/bin/perl
use strict;
use warnings;
use Parallel::ForkManager;
use LWP::Simple;
my @array = (
??????????'http://mirrors.163.com/centos/5.5/os/i386/CentOS/Cluster_Administration-as-IN-5.2-1.el5.centos.noarch.rpm',
??????????'http://mirrors.163.com/centos/5.5/os/i386/CentOS/Cluster_Administration-hi-IN-5.2-1.el5.centos.noarch.rpm',
??????????'http://mirrors.163.com/centos/5.5/os/i386/CentOS/Global_File_System-or-IN-5.2-1.el5.centos.noarch.rpm',
??????????'http://mirrors.163.com/centos/5.5/os/i386/CentOS/Virtualization-it-IT-5.2-11.el5.centos.noarch.rpm',
??????????'http://mirrors.163.com/centos/5.5/os/x86_64/CentOS/Global_File_System-zh-CN-5.2-1.el5.centos.noarch.rpm',
??????????'http://121.207.250.132/my/mybt_5520_client.exe',
??????????'http://dl.91.com/my/my_5520_client.exe',
??????????'ftp://download1.91.com/my/my_5520_client.exe',
??????????'ftp://download2.91.com/jz/jz_3560_client.exe',
??????????'http://dl.91.com/ty/TY_1328_client.exe',
??????????'ftp://download2.91.com/kx/kx_3500_client.exe',
??????????'http://www.sina.com/',
??????????'http://www.qq.com/'
);
my $max_process = 5;
my $pm = new Parallel::ForkManager( $max_process );
foreach my $link (@array){
????????$pm->start and next;
????????my ($fn) = $link =~ /^.*/(.*?)$/;
????????if (!$fn) {
??????????warn "Can not determine filename from $fnn";
????????}else{
??????????$0 .= " ".$fn;
??????????print "Geting $fn from $linkn";
??????????my $cs = getstore($link,$fn);
??????????print "$link downloaded.reponse code:$csn";
????????}
????????$pm->finish;
}
|
程序中提供了一个URL文件列表，使用Parallel::ForkManager创建多个进程同时下载，最大进程数为5。用ps命令查看系统进程如下所示：
/usr/sbin/sshd
?? ? ?4718 ?0.0 ?0.2 ?10084 ?2860 ? ? ? ? ?Ss ? 02:35 ? 0:00 ?_ sshd: @?
?? ? ?4720 ?0.0 ?0.1 ? 4916 ?1484 ? ? Ss ? 02:35 ? 0:00 ?| ? _ -bash
?? ? ?3301 ?1.8 ?0.4 ? 6668 ?4784 ? ? S+ ? 03:57 ? 0:00 ?| ? ? ? _
perl 1.pl
?? ? ?3308 ?8.0 ?0.7 ? 9632 ?7484 ? ? S+ ? 03:57 ? 0:00 ?| ? ? ? ? ? _ 1.pl my_5520_client.exe
?? ? ?3309 ?5.6 ?0.6 ? 9168 ?7088 ? ? S+ ? 03:57 ? 0:00 ?| ? ? ? ? ? _ 1.pl my_5520_client.exe
?? ? ?3310 ?3.3 ?0.6 ? 9168 ?7088 ? ? S+ ? 03:57 ? 0:00 ?| ? ? ? ? ? _ 1.pl jz_3560_client.exe
?? ? ?3311 ?7.3 ?0.7 ? 9632 ?7484 ? ? S+ ? 03:57 ? 0:00 ?| ? ? ? ? ? _ 1.pl TY_1328_client.exe
?? ? ?3312 ?8.0 ?0.6 ? 9172 ?7088 ? ? S+ ? 03:57 ? 0:00 ?| ? ? ? ? ? _ 1.pl kx_3500_client.exe
另外，介绍三个函数
run_on_finish ? 子进程finish之后调用的函数
run_on_start 子进程start之后调用的函数
run_on_wait 当子进程需要等待时自动调用的函数
例程：
| #!/usr/bin/perl -w
use lib '.';
use strict;
use Parallel::ForkManager;
my $max_procs = 5;
my @names = qw( Fred Jim Lily Steve Jessica Bob Dave Christine Rico Sara );
# hash to resolve PID's back to child specific information
my $pm = new Parallel::ForkManager($max_procs);
# Setup a callback for when a child finishes up so we can
# get it's exit code
$pm->run_on_finish(
??sub { my ($pid,$exit_code,$ident) = @_;
????print "** $ident just got out of the pool ".
??????"with PID $pid and exit code: $exit_coden";
??}
);
$pm->run_on_start(
??sub { my ($pid,$ident)=@_;
????print "** $ident started,pid: $pidn";
??}
);
$pm->run_on_wait(
??sub {
????print "** Have to wait for one children ...n"
??},
??0.5,
);
foreach my $child ( 0 .. $#names ) {
??my $pid = $pm->start($names[$child]) and next;
??# This code is the child process
??print "This is $names[$child],Child number $childn";
??sleep ( 2 * $child );
??print "$names[$child],Child $child is about to get out...n";
??sleep 1;
??$pm->finish($child); # pass an exit code to finish
}
print "Waiting for Children...n";
$pm->wait_all_children;
print "Everybody is out of the pool!n";
|
