argonne-lcf / alcl

Argonne Leadership Computing Facility OpenCL tutorial

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Argonne Leadership Computing Facility OpenCL / L0 tutorial.

Examples are provided in C, C++, Python and Ruby.

# Create all the executable
make
# Run all the executable
make run

For Python examples you need to have pyopencl installed. For Ruby you need the opencl_ruby_ffi gem installed.

Introduction to the API

platform (Python: query_platform.py)

• Simple OpenCL C example to list your platform
• make run_platform

tiny_clinfo

• List all the device for all the platform in your system (inspired by the "standard" clinfo tools)
• make run_tiny_clinfo

Hello world and ID

my_first_kernel

• Hello world kernel. Each work-item will print is global_id (rank in MPI terminology)
• make run_my_first_kernel
• Usage: ./my_first_kernel platform_id device_id global_size local_size

verbose

• Verbose kernel, more introspective. Each work-item will print is global and local id. And the associated total size.
• make run_verbose
• Usage: ./my_first_kernel platform_id device_id global_size local_size

Where do I put my kernel?

read_cl

• Similar to verbose, but we read the kernel string from a file
• make run_read_cl
• Usage: ./read_cl platform_id device_id global_size local_size

read_bincl

• Similar to verbose, but we precopile the kernel and then read it
• make run_read_bincl
• Usage: ./read_bincl platform_id device_id global_size local_size

read_elfcl (C and C++ only)

• Similar to verbose, but store the precompiler opencl kernel inside the execetuable.
• make run_read_elfcf
• Usage: ./read_elfcl platform_id device_id global_size local_size

Buffer

buffer (Python: buffer_usage.py)

• How to create and use buffer
• make run_buffer

Ordering

event_unorder

• How to use and out of order queue
• make run_event_unorder
• Usage: ./event_unorder platform_id device_id global_size local_size number_of_kernel_launch

event_order

• How to use and out of order queue and event to impose and order
• make run_event_order
• Usage: ./event_unorder platform_id device_id global_size local_size number_of_kernel_launch

Profiling

profiling

• How to measure exution time of a kernel
• make run_profiling