--- OpenCL/OpenCL.pm 2011/11/16 06:22:20 1.8 +++ OpenCL/OpenCL.pm 2011/11/17 01:36:52 1.9 @@ -10,7 +10,40 @@ This is an early release which might be useful, but hasn't seen much testing. -=head1 HELPFUL RESOURCES +=head2 OpenCL FROM 10000 FEET HEIGHT + +Here is a high level overview of OpenCL: + +First you need to find one or more OpenCL::Platforms (kind of like +vendors) - usually there is only one. + +Each platform gives you access to a number of OpenCL::Device objects, e.g. +your graphics card. + +From a platform and some devices, you create an OpenCL::Context, which is +a very central object in OpenCL: Once you have a context you can create +most other objects: + +OpenCL::Program objects, which store source code and, after building +("compiling and linking"), also binary programs. For each kernel function +in a program you can then create an OpenCL::Kernel object which represents +basically a function call with argument values. + +OpenCL::Memory objects of various flavours: OpenCL::Buffers objects (flat +memory areas, think array) and OpenCL::Image objects (think 2d or 3d +array) for bulk data and input and output for kernels. + +OpenCL::Sampler objects, which are kind of like texture filter modes in +OpenGL. + +OpenCL::Queue objects - command queues, which allow you to submit memory +reads, writes and copies, as well as kernel calls to your devices. They +also offer a variety of methods to synchronise request execution, for +example with barriers or OpenCL::Event objects. + +OpenCL::Event objects are used to signal when something is complete. + +=head2 HELPFUL RESOURCES The OpenCL spec used to develop this module (1.2 spec was available, but no implementation was available to me :). @@ -21,6 +54,29 @@ http://www.khronos.org/registry/cl/sdk/1.1/docs/man/xhtml/ +=head1 BASIC WORKFLOW + +To get something done, you basically have to do this once: + +Find some platform (e.g. the first one) and some device (e.g. the first +device you can find), and create a context from those. + +Create a command queue from your context, and program objects from your +OpenCL source code, build the programs. + +Create kernel objects for all kernels you want to use. + +Then, to execute stuff, you repeat this: + +Create some input and output buffers from your context. Initialise the +input buffers with data. Set these as arguments to your kernel. + +Enqueue the kernel execution. + +Enqueue buffer reads for your output buffer to read results. + +The next section shows how this can be done. + =head1 EXAMPLES =head2 Enumerate all devices and get contexts for them. @@ -39,7 +95,7 @@ my $dev = ((OpenCL::platforms)[0]->devices)[0]; my $ctx = $dev->context_simple; - my $queue = $ctx->command_queue_simple ($dev); + my $queue = $ctx->queue ($dev); =head2 Print all supported image formats of a context. @@ -150,11 +206,11 @@ arrays (C), while this module explicitly expects the components as separate arguments- -=item * Where possible, the row_pitch value is calculated from the perl -scalar length and need not be specified. +=item * Where possible, one of the pitch values is calculated from the +perl scalar length and need not be specified. =item * When enqueuing commands, the wait list is specified by adding -extra arguments to the function - everywhere a C<$wait_events...> argument +extra arguments to the function - anywhere a C<$wait_events...> argument is documented this can be any number of event objects. =item * When enqueuing commands, if the enqueue method is called in void @@ -197,7 +253,7 @@ Comverts an error value into a human readable string. -=item $str = OpenCL::err2str $enum +=item $str = OpenCL::enum2str $enum Converts most enum values (inof parameter names, image format constants, object types, addressing and filter modes, command types etc.) into a @@ -277,9 +333,9 @@ L -=item $queue = $ctx->command_queue_simple ($device) +=item $queue = $ctx->queue ($device, $properties) -Convenience function to create a new OpenCL::Queue object from the context and the given device. +Create a new OpenCL::Queue object from the context and the given device. L