The document discusses various approaches for handling concurrent and asynchronous tasks in different programming languages and frameworks. It covers concepts like processes, threads, coroutines, event loops, and asynchronous I/O. Specific technologies summarized include POE, Twisted, AnyEvent, Java NIO, and servers like Squid, Apache, and Nginx. The document provides code examples to illustrate how concurrent programming is implemented using these different strategies.

1. Achilles Xu
formalin14@gmail.com

2. Contents
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3. • I/O CPU
/ CPU
• I/O
CPU
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4. •
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5. • linux win
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• top
cpu

6. my @urllist = read_list();
my @pids;
for my $url (@urllist) {
my $pid = fork();
if ($pid == 0) {
print get($url);
exit;
} elsif ($pid > 0) {
push @pids, $pid; # ID
}
}
waitpid($_, ...) for @pids; #
# do other nonconcurrent jobs

7. my @pids;
for ( 1 .. 20) {
my $pid = fork;
if ($pid == 0) {
while (1) {
my $task = lock_and_get_task();
do_task($task);
sleep 1;
}
exit;
} elsif ($pid > 0) {
push @pids, $pid;
}
}
waitpid($_, ...) for @pids;

8. •
• top cpu
• perl 5.8.5 perl 5.8.8
LWP

9. use threads;
sub load_url {
print get($_[0]);
}
my @urllist = read_url_list();
my @tids;
for my $url (@urllist) {
my $tid = threads->create(&load_url, $url);
push @tids, $tid; # ID
}
$_->join for @tids; # waitpid
# do other things

10. use threads;
use threads::shared;
my @queue : shared;
for (1 .. 6) {
threads->create( sub {
while (1) {
my $task;
{ lock @queue;
$task = shift @queue;
}
do_task($task);
threads::sleep(1);
}
}
}
while (1) { generate_task(@queue); threads::sleep(1); }

11. java.lang.Thread
• linux windows
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12. • C Python GIL
• Coro Coroutines
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13. Coro
• I/O CPU
• cede CPU
• Perl6 async

14. Coro
use Coro;
async {
# some asynchronous thread of execution
print "2n";
cede; # yield back to main
print "4n";
};
print "1n";
cede; # yield to coro
print "3n";
cede; # and again

15. • I/O
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•
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16. • select
• poll select
• epoll I/O
• I/O
sendfile

17. • POE
• Twisted
• AnyEvent
• Java NIO

18. POE
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• yield
• Session
• $heap
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19. POE
sub handler_increment {
my ($kernel, $heap, $session) = @_
[KERNEL, HEAP, SESSION];
print "Session ", $session->ID, "
counted to ", ++$heap->{count}, ".n";
$kernel->yield('increment') if
$heap->{count} < 10;
}

20. Twisted
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• POE N
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• dns connect send
request got first byte.... hook
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21. Twisted
d = conect_to_server()
d.addCallback(login_user)
d.addErrback(reconnect_to_server)
reactor.run()

22. AnyEvent
• libevent
EV
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• Coro POE

23. Java NIO
• linux windows
• Channel

24. • Squid 2.x
• Apache
• Nginx

25. Squid 2.x
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• sendfile
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• COSS
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26. Apache
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• php

27. Nginx
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• epoll kqueue sendfile writev
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28. • Questions