GPGPU stands for General-Purpose computation on Graphics Processing Units, also known as GPU Computing. Graphics Processing Units (GPUs) are high-performance many-core processors capable of very high computation and data throughput. Once specially designed for computer graphics and difficult to program, today’s GPUs are general-purpose parallel processors with support for accessible programming interfaces and industry-standard languages such as C. Developers who port their applications to GPUs often achieve speedups of orders of magnitude vs. optimized CPU implementations.
Indeed GPGPUs are going to be a very useful tool for Luxrender.
What is OpenCL ?
OpenCL? is the first open, royalty-free standard for cross-platform, parallel programming of modern processors found in personal computers, servers and handheld/embedded devices. OpenCL (Open Computing Language) greatly improves speed and responsiveness for a wide spectrum of applications in numerous market categories from gaming and entertainment to scientific and medical software.
Luxrender developer team want to continue to support a wide range of platforms and OS (i.e. Linux, Window, MacOS, ATI GPGPUS, NVIDIA GPUs, etc.). Before OpenCL, each vendor has its own (i.e. proprietary) set of tools to develop GPGPUs application: NVIDIA CUDA, ATI Stream SDK, etc. OpenCL solves this problem and has been seen by Luxrender developer team as the way to go since the release of the first specifications.
Introducing OpenCL in Luxrender
This is a list of the steps done up to now to introduce OpenCL support in Luxrender. Indeed it is a quite complex task that requires a lot of tests, experiments and steps.
ATI released OpenCL beta SDK with hardware support
The first step was the ATI release of a OpenCL beta SDK in October with the support for GPGPUs in HD4xxx and new HD5xxx generation. This allowed Luxrender developers to do the first tests.
The first test: MandelCPU Vs MandelGPU
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