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Re: Win32::GUI and threads issue

by marioroy (Vicar)
on Jan 17, 2019 at 07:25 UTC ( #1228680=note: print w/replies, xml ) Need Help??


in reply to Win32::GUI and threads issue

Hi Garden Dwarf,

Based on your code, the following runs for me on a Windows 7 VM running Perl 5.26.1. Workers persist in the background. Two queues (inbound and outbound) are used. Due to lack of time, I apologize for not displaying to the terminal. The goal was seeing text display in the windows dialog. And yes, there you go. :)

I added a state variable ($running) in the event a long running job so not to impact the main app.

#!/bin/perl # Win32::GUI and threads issue # https://www.perlmonks.org/?node_id=1228580 use strict; use warnings; # One may run threads + MCE::Shared. This works very well. # Why MCE::Shared one might ask? Well, it handles serialization # of data objects automatically. E.g. passing array refs. use threads; use MCE::Shared; my $queue_in = MCE::Shared->queue(); my $queue_ou = MCE::Shared->queue(); my $t_amount = 3; # Amount of threads to create my $running = 0; my $textbox; my $win; # Important, spawn threads early before loading Win32::GUI. threads->new('producer') for 1..$t_amount; # Run the main app or consumer afterwards. consumer(); # Voila :) exit; sub consumer { require Win32::GUI; # Initialize window $win = new Win32::GUI::Window( -left => 0, -top => 0, -width => 300, -height => 300, -name => "Window", -text => "Test", ); $win->InvalidateRect(1); $textbox = $win->AddTextfield( -name => "Output", -left => 5, -top => 5, -width => 275, -height => 255, -text => "", -multiline => 1, ); # Start application (calls draw_Timer) $win->AddTimer('draw', 333); $win->Show(); Win32::GUI::Dialog(); } sub producer { $SIG{QUIT} = sub { threads->exit(); }; while ( defined ( my $next_args = $queue_in->dequeue ) ) { my ( $c, $begin, $end ) = @{ $next_args }; my @ret = compute($begin, $end); sleep 2; # simulate a long running process $queue_ou->enqueue([ $c, @ret ]); } } sub Window_Terminate { $queue_in->end(); $_->kill('QUIT') for threads->list; -1; } sub draw_Timer { # Enqueue range of computation to background threads if ( $running == 0 ) { $running = 1; foreach my $c (1..$t_amount) { my $d = $c - 1; $queue_in->enqueue([ $c, $d*10, $d*10+10 ]); } } # Obtain data once background threads have completed if ( $running == 1 && $queue_ou->pending == $t_amount ) { $running = 0; my @ordered_ret; foreach my $c (1..$t_amount) { my $ret = $queue_ou->dequeue(); my $c = shift(@{ $ret }) - 1; # array-based-zero $ordered_ret[$c] = ""; foreach my $data (@{ $ret }) { $ordered_ret[$c] .= "|".$data; } $ordered_ret[$c] .= "\n"; } $textbox->Append($_) for @ordered_ret; } } sub compute { my ($begin, $end) = (shift, shift); my (@tbl, $cpt); for ($cpt = $begin; $cpt < $end; $cpt++) { push @tbl, $cpt; } return @tbl; }

Regards, Mario

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Re^2: Win32::GUI and threads issue
by marioroy (Vicar) on Jan 17, 2019 at 07:30 UTC

    MCE::Hobo works as well. The following are the changes to the above solution. The API is similar to threads.

    13c13 < use threads; --- > use MCE::Hobo; 25c25 < threads->new('producer') for 1..$t_amount; --- > MCE::Hobo->new('producer') for 1..$t_amount; 67c67 < threads->exit(); --- > MCE::Hobo->exit(); 79c79 < $_->kill('QUIT') for threads->list; --- > $_->kill('QUIT') for MCE::Hobo->list;

      Hi Mario,

      I've implemented your solution into my main code, and it is working fine. Thanks a lot!

      After having proceeded to some benchs, I noticed that dequeuing slows down the process. I tried with different amounts of threads and the performances are good, but unfortunately not good enough to have a real-time image processing. I know, perl may not be the right choice for this but I wanted to give it a try.

      On the other hand, adding tasks to a queue can be optimized by adding all of them at once ($queue_in->enqueue(task1,task2,...)). Processing time is reduced significantly compared to enqueuing each task separately. The code would look like this:

      my @taskslist; foreach my $c (1..$t_amount) { my $d = $c - 1; push(@taskslist,[ $c, $d*10, $d*10+10 ]); } $queue_in->enqueue(@taskslist);

      Well, thanks again and if you have a suggestion of how to increase the performances (staying with Perl), it would be nice!

        Hi Garden Dwarf

        Yes, batching is helpful to improve performance. I met to try Thread::Queue as well. For extra performance try passing an array ref like the demo to minimize memory copies inside Perl. Below is an example using Thread::Queue which does not involve sockets for IPC. It is faster than MCE::Shared on the Windows platform.

        #!/bin/perl # Win32::GUI and threads issue # https://www.perlmonks.org/?node_id=1228580 use strict; use warnings; # One may run threads + MCE::Shared. This works very well. # Why MCE::Shared one might ask? Well, it handles serialization # of data objects automatically. E.g. passing array refs. # # Thread::Queue on the Windows platform will give you better # performance. It means having to choose a serializer (a fast one) # and handle data serialization at the application level. use threads; use Thread::Queue; use CBOR::XS; my $queue_in = Thread::Queue->new(); my $queue_ou = Thread::Queue->new(); my $t_amount = 3; # Amount of threads to create my $running = 0; my $textbox; my $win; # Important, spawn threads early before loading Win32::GUI. threads->new('producer') for 1..$t_amount; # Run the main app or consumer afterwards. consumer(); # Voila :) exit; sub consumer { require Win32::GUI; # Initialize window $win = new Win32::GUI::Window( -left => 0, -top => 0, -width => 300, -height => 300, -name => "Window", -text => "Test", ); $win->InvalidateRect(1); $textbox = $win->AddTextfield( -name => "Output", -left => 5, -top => 5, -width => 275, -height => 255, -text => "", -multiline => 1, ); # Start application (calls draw_Timer) $win->AddTimer('draw', 333); $win->Show(); Win32::GUI::Dialog(); } sub producer { threads->detach(); while ( defined ( my $next_args = $queue_in->dequeue ) ) { my ( $c, $begin, $end ) = @{ decode_cbor($next_args) }; my @ret = compute($begin, $end); sleep 2; # simulate a long running process $queue_ou->enqueue( encode_cbor([ $c, @ret ]) ); } } sub Window_Terminate { $queue_in->end(); -1; } sub draw_Timer { # Enqueue range of computation to background threads if ( $running == 0 ) { $running = 1; foreach my $c (1..$t_amount) { my $d = $c - 1; $queue_in->enqueue( encode_cbor([ $c, $d*10, $d*10+10 ]) ); } } # Obtain data once background threads have completed if ( $running == 1 && $queue_ou->pending == $t_amount ) { $running = 0; my @ordered_ret; foreach my $c (1..$t_amount) { my $ret = decode_cbor( $queue_ou->dequeue() ); my $c = shift(@{ $ret }) - 1; # array-based-zero $ordered_ret[$c] = ""; foreach my $data (@{ $ret }) { $ordered_ret[$c] .= "|".$data; } $ordered_ret[$c] .= "\n"; } $textbox->Append($_) for @ordered_ret; } } sub compute { my ($begin, $end) = (shift, shift); my (@tbl, $cpt); for ($cpt = $begin; $cpt < $end; $cpt++) { push @tbl, $cpt; } return @tbl; }

        By all means, batch accordingly if possible to further increase performance. Enable your creativity in the design. Looks like fun :)

        Regards, Mario

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