## MCE::Shared for Perl This document describes MCE::Shared version 1.840. ### Description This module provides data sharing capabilities for [MCE](https://github.com/marioroy/mce-perl) supporting threads and processes. MCE::Hobo, included with the distribution, provides threads-like parallelization for running code asynchronously. Unlike threads, Hobo workers are spawned as processes having unique PIDs. ### Synopsis ```perl use MCE::Hobo; use MCE::Shared; my $N = shift || 4_000_000; my $pi = MCE::Shared->scalar( 0.0 ); my $seq = MCE::Shared->sequence( { chunk_size => 200_000, bounds_only => 1 }, 0, $N - 1 ); sub compute_pi { my ( $wid ) = @_; while ( my ( $beg, $end ) = $seq->next ) { my ( $_pi, $t ) = ( 0.0 ); for my $i ( $beg .. $end ) { $t = ( $i + 0.5 ) / $N; $_pi += 4.0 / ( 1.0 + $t * $t ); } $pi->incrby( $_pi ); } return; } MCE::Hobo->create( \&compute_pi, $_ ) for ( 1 .. 8 ); # ... do other stuff ... $_->join() for MCE::Hobo->list(); printf "pi = %0.13f\n", $pi->get / $N; # 3.1415926535898 ``` The next demonstration does the same thing using a MCE Model. ```perl use MCE::Flow; use MCE::Shared; my $N = shift || 4_000_000; my $pi = MCE::Shared->scalar( 0.0 ); sub compute_pi { my ( $wid, $beg_seq, $end_seq ) = @_; my ( $_pi, $t ) = ( 0.0 ); foreach my $i ( $beg_seq .. $end_seq ) { $t = ( $i + 0.5 ) / $N; $_pi += 4.0 / ( 1.0 + $t * $t ); } $pi->incrby( $_pi ); } # Compute bounds only, workers receive [ begin, end ] values MCE::Flow::init( chunk_size => 200_000, max_workers => 8, bounds_only => 1 ); mce_flow_s sub { compute_pi( MCE->wid, $_->[0], $_->[1] ); }, 0, $N - 1; printf "pi = %0.13f\n", $pi->get / $N; # 3.1415926535898 ``` ### Installation and Dependencies MCE::Shared enables extra functionality on systems with IO::FDPass installed. Without it, MCE::Shared is unable to send file descriptors to the shared-manager process. The use applies to Condvar, Queue, and Handle (mce_open). IO::FDpass isn't used for anything else. To install this module type the following: # Appends IO::FDPass to PREREQ_PM if a C compiler is available. perl Makefile.PL # Or exclude the IO::FDPass check and not append to PREREQ_PM. MCE_PREREQ_EXCLUDE_IO_FDPASS=1 perl Makefile.PL make make test make install This module requires Perl 5.10.1 or later to run. MCE::Shared utilizes the following modules: bytes constant overload Carp IO::FDPass 1.2+ (optional, recommended on UNIX and Windows) MCE::Mutex 1.832+ MCE::Util 1.832+ MCE::Signal 1.832+ POSIX Scalar::Util Sereal::Decoder 3.015+ (optional) Sereal::Encoder 3.015+ (optional) Socket Storable 2.04+ (default when Sereal isn't available) Symbol Test::More 0.45+ (for make test only) Time::HiRes The IO::FDPass module applies to MCE::Shared::{ Condvar, Handle, and Queue }. ### Further Reading The MCE::Shared module is described at https://metacpan.org/pod/MCE::Shared. The MCE::Hobo module is described at https://metacpan.org/pod/MCE::Hobo. See [MCE::Examples](https://metacpan.org/pod/MCE::Examples) and [MCE Cookbook](https://github.com/marioroy/mce-cookbook) for recipes. ### Copyright and Licensing Copyright (C) 2016-2018 by Mario E. Roy This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself: a) the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version, or b) the "Artistic License" which comes with this Kit. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See either the GNU General Public License or the Artistic License for more details. You should have received a copy of the Artistic License with this Kit, in the file named "LICENSE". If not, I'll be glad to provide one. You should also have received a copy of the GNU General Public License along with this program in the file named "Copying". If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA or visit their web page on the internet at http://www.gnu.org/copyleft/gpl.html.