Coro-Multicore/Multicore.pm

=head1 NAME

Coro::Multicore - make coro threads on multiple cores with specially supported modules

=head1 SYNOPSIS

 use Coro::Multicore;

 # or, if you want it disabled by default (e.g. to use it from a module)
 use Coro::Multicore ();

=head1 DESCRIPTION

While L<Coro> threads (unlike ithreads) provide real threads similar to
pthreads, python threads and so on, they do not run in parallel to each
other even on machines with multiple CPUs or multiple CPU cores.

This module lifts this restriction under two very specific but useful
conditions: firstly, the coro thread executes in XS code and does not
touch any perl data structures, and secondly, the XS code is specially
prepared to allow this.

This means that, when you call an XS function of a module prepared for it,
this XS function can execute in parallel to any other Coro threads.

The mechanism to support this is easily added to existing modules
and is independent of L<Coro> or L<Coro::Multicore>, and therefore
could be used, without changes, with other, similar, modules, or even
the perl core, should it gain real thread support anytime soon. See
L<http://perlmulticore.schmorp.de/> for more info on how to prepare a
module to allow parallel execution. Preparing an existing module is easy,
doesn't add much overhead and no dependencies.

This module is an L<AnyEvent> user (and also, if not obvious, uses
L<Coro>).

=head1 HOW TO USE IT

It could hardly be simpler - if you use coro threads, and before you call
a supported lengthy operation implemented in XS, use this module and other
coro threads can run in parallel:

   use Coro::Multicore;

This module has no important API functions to learn or remember. All you
need to do is I<load> it before you can take advantage of it.

=head2 EXPORTS

This module does not (at the moment) export any symbols. It does, however,
export "behaviour" - if you use the default import, then Coro::Multicore
will be enabled for all threads and all callers in the whole program:

   use Coro::Multicore;

In a module where you don't control what else might be loaded and run, you
might want to be more conservative, and not import anything. This has the
effect of not enabling the functionality by default, so you have to enable
it per scope:

   use Coro::Multicore ();

   sub myfunc {
      Coro::Multicore::scoped_enable;

      # from here to the end of this function, and in any functions
      # callsed from this function, tasks will be executed asynchronously.

   }

=head1 API FUNCTIONS

=over 4

=item $previous = Coro::Multicore::enable [$enable]

This function enables (if C<$enable> is true) or disables (if C<$enable>
is false) the multicore functionality globally. By default, it is enabled.

This can be used to effectively disable this module's functionality by
default, and enable it only for selected threads or scopes, by calling
C<Coro::Multicore::scope_enable>.

The function returns the previous value of the enable flag.

=item Coro::Multicore::scoped_enable

This function instructs Coro::Multicore to handle all requests executed
in the current coro thread, from the call to the end of the current scope.

Calls to C<scoped_enable> and C<scoped_disable> don't nest very well at
the moment, so don't nest them.

=item Coro::Multicore::scoped_disable

The opposite of C<Coro::Multicore::scope_disable>: instructs Coro::Multicore to
I<not> handle the next multicore-enabled request.

=back

=cut

package Coro::Multicore;

use Coro ();
use AnyEvent ();

BEGIN {
   our $VERSION = 0.02;

   use XSLoader;
   XSLoader::load __PACKAGE__, $VERSION;
}


sub import {
   if (@_ > 1) {
      require Carp;
      Carp::croak ("Coro::Multicore does not export any symbols");
   }

   enable 1;
}

our $WATCHER = AE::io fd, 0, \&poll;

=head1 INTERACTION WITH OTHER SOFTWARE

TODO

=head1 BUGS

At the moment, threads that were created once will never be freed. They
will be reused for asynchronous requests, though, so a slong as you limit
the maximum number of concurrent asynchronous tasks, this will also limit
the maximum number of threads created.

Future versions will likely lift this limitation.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://software.schmorp.de/pkg/AnyEvent-XSThreadPool.html

=cut

1

Revision:	1.5
Committed:	Mon Jun 29 13:15:53 2015 UTC (8 years, 11 months ago) by root
Branch:	MAIN
Changes since 1.4:	+52 -13 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Coro::Multicore - make coro threads on multiple cores with specially supported modules
4
5			=head1 SYNOPSIS
6
7			use Coro::Multicore;
8
9	root	1.5	# or, if you want it disabled by default (e.g. to use it from a module)
10			use Coro::Multicore ();
11
12	root	1.1	=head1 DESCRIPTION
13
14	root	1.2	While L<Coro> threads (unlike ithreads) provide real threads similar to
15	root	1.3	pthreads, python threads and so on, they do not run in parallel to each
16	root	1.2	other even on machines with multiple CPUs or multiple CPU cores.
17
18			This module lifts this restriction under two very specific but useful
19			conditions: firstly, the coro thread executes in XS code and does not
20			touch any perl data structures, and secondly, the XS code is specially
21			prepared to allow this.
22
23			This means that, when you call an XS function of a module prepared for it,
24			this XS function can execute in parallel to any other Coro threads.
25
26	root	1.3	The mechanism to support this is easily added to existing modules
27			and is independent of L<Coro> or L<Coro::Multicore>, and therefore
28			could be used, without changes, with other, similar, modules, or even
29			the perl core, should it gain real thread support anytime soon. See
30	root	1.5	L<http://perlmulticore.schmorp.de/> for more info on how to prepare a
31			module to allow parallel execution. Preparing an existing module is easy,
32			doesn't add much overhead and no dependencies.
33	root	1.3
34			This module is an L<AnyEvent> user (and also, if not obvious, uses
35			L<Coro>).
36
37			=head1 HOW TO USE IT
38
39			It could hardly be simpler - if you use coro threads, and before you call
40			a supported lengthy operation implemented in XS, use this module and other
41			coro threads can run in parallel:
42
43			use Coro::Multicore;
44
45			This module has no important API functions to learn or remember. All you
46			need to do is I<load> it before you can take advantage of it.
47
48	root	1.5	=head2 EXPORTS
49
50			This module does not (at the moment) export any symbols. It does, however,
51			export "behaviour" - if you use the default import, then Coro::Multicore
52			will be enabled for all threads and all callers in the whole program:
53
54			use Coro::Multicore;
55
56			In a module where you don't control what else might be loaded and run, you
57			might want to be more conservative, and not import anything. This has the
58			effect of not enabling the functionality by default, so you have to enable
59			it per scope:
60
61			use Coro::Multicore ();
62
63			sub myfunc {
64			Coro::Multicore::scoped_enable;
65
66			# from here to the end of this function, and in any functions
67			# callsed from this function, tasks will be executed asynchronously.
68
69			}
70
71	root	1.4	=head1 API FUNCTIONS
72	root	1.3
73	root	1.4	=over 4
74
75			=item $previous = Coro::Multicore::enable [$enable]
76
77			This function enables (if C<$enable> is true) or disables (if C<$enable>
78			is false) the multicore functionality globally. By default, it is enabled.
79
80			This can be used to effectively disable this module's functionality by
81			default, and enable it only for selected threads or scopes, by calling
82			C<Coro::Multicore::scope_enable>.
83
84			The function returns the previous value of the enable flag.
85	root	1.2
86	root	1.4	=item Coro::Multicore::scoped_enable
87
88			This function instructs Coro::Multicore to handle all requests executed
89			in the current coro thread, from the call to the end of the current scope.
90
91			Calls to C<scoped_enable> and C<scoped_disable> don't nest very well at
92			the moment, so don't nest them.
93
94			=item Coro::Multicore::scoped_disable
95
96			The opposite of C<Coro::Multicore::scope_disable>: instructs Coro::Multicore to
97			I<not> handle the next multicore-enabled request.
98	root	1.1
99	root	1.3	=back
100
101	root	1.1	=cut
102
103			package Coro::Multicore;
104
105			use Coro ();
106			use AnyEvent ();
107
108			BEGIN {
109			our $VERSION = 0.02;
110
111			use XSLoader;
112			XSLoader::load __PACKAGE__, $VERSION;
113			}
114
115	root	1.5
116			sub import {
117			if (@_ > 1) {
118			require Carp;
119			Carp::croak ("Coro::Multicore does not export any symbols");
120			}
121
122			enable 1;
123			}
124
125	root	1.1	our $WATCHER = AE::io fd, 0, \&poll;
126
127	root	1.5	=head1 INTERACTION WITH OTHER SOFTWARE
128
129			TODO
130
131			=head1 BUGS
132
133			At the moment, threads that were created once will never be freed. They
134			will be reused for asynchronous requests, though, so a slong as you limit
135			the maximum number of concurrent asynchronous tasks, this will also limit
136			the maximum number of threads created.
137
138			Future versions will likely lift this limitation.
139
140	root	1.1	=head1 AUTHOR
141
142			Marc Lehmann <schmorp@schmorp.de>
143			http://software.schmorp.de/pkg/AnyEvent-XSThreadPool.html
144
145			=cut
146
147			1
148