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Re^2: Socket hang. (Windows or Perl? Solutions?) (Updated)

by marioroy (Priest)
on Sep 01, 2018 at 04:25 UTC ( #1221489=note: print w/replies, xml ) Need Help??


in reply to Re: Socket hang. (Windows or Perl? Solutions?) (Updated)
in thread Socket hang. (Windows or Perl? Solutions?) (Updated)

Hi again! BrowserUk's demo is possible for Perl lacking threads support. A condition variable is needed to prevent a race condition, especially for processes that spawn quickly. For example, the 2nd worker attempting to connect before the 1st worker initiates the connection.

#! perl -slw # Parallel example for Perl not built with threads support. # Based on https://www.perlmonks.org/?node_id=897591. use strict; use Time::HiRes qw[ time usleep ]; use MCE::Hobo; use MCE::Shared; use IO::Socket; our $port //= 12345; my $condvar = MCE::Shared->condvar; my $svrN = MCE::Shared->scalar( 0 ); my $clientN = MCE::Shared->scalar( 0 ); my $is_winenv = ( $^O =~ /mswin|mingw|msys|cygwin/i ); my $start = time; mce_async { my $svr = IO::Socket::INET->new( Listen => SOMAXCONN, Reuse =>1, LocalPort => $port, Timeout => 0.1, ) or die $!; # signal the client ready $condvar->signal; while( my $client = $svr->accept ) { my $in = <$client>; print $client "echod:$in"; syswrite($client, '0') if $is_winenv; $client->shutdown( 2 ); close $client; $svrN->incr; } }; mce_async { # wait for the server connection $condvar->wait; while( 1 ) { my $svr = IO::Socket::INET->new( PeerHost => 'localhost', PeerPort => $port, Reuse => 1, Timeout => 0.1, ) or usleep( 10_000 ), next; sleep 0; print $svr $clientN->incr; my $echo = <$svr>; sleep 0; syswrite($svr, '0') if $is_winenv; $svr->shutdown( 2 ); close $svr; sleep 0; } }; $|++; while( usleep 100_000 ) { my ( $n1, $n2 ) = ( $svrN->get, $clientN->get ); printf "\rserver:$n1 client:$n2 cycles: %.3f/sec", $n1 / ( time() - $start ); }

Note: MCE::Shared involves sockets. So it will not run as fast as threads::shared. Not to worry, it's not far behind.

Strawberry Perl

Y:\>perl demo_thr.pl server:29889 client:29889 cycles: 2119.429/secTerminating on signal SI +GINT(2) Y:\>perl demo_mce.pl server:35619 client:35620 cycles: 1771.711/secTerminating on signal SI +GINT(2)

Cygwin

$ perl demo_thr.pl server:31879 client:31879 cycles: 2128.663/sec $ perl demo_mce.pl server:31690 client:31691 cycles: 1856.834/sec

Regards, Mario

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