What is the OpenCL platform model?

With a growing need for higher computational power for compute-intensive applications, conventional approaches to addressing it lack the necessary capability. Before the concept of heterogeneous computingUtilization of diverse types of processors within a system to improve overall performance and efficiency., the industry was focused on facilitating this exponential need by increasing the number of processors. However, this approach was unfavorable due to factors such as:

• Scalability: Managing and synchronizing the communication between the growing number of processors was challenging, causing higher costs and impacting overall performance.

• Complexity: Designing and optimizing such architectures was challenging, making developing software intricate. 

• Performance bottlenecks: Experiencing increased processors, performance bottlenecksA point of congestion or limitation in a system that hinders its overall performance. arise, including limited memory bandwidth, communication latency, and contention for shared resources, hindering overall system efficiency and responsiveness.

• Power consumption: Adding more processors caused higher power consumption, which affected cost-effectiveness and environmental sustainability.

To address these challenging problems, heterogeneous computing became the only viable option. In heterogeneous computing, we divide our work among multiple workers. To put this in perspective, the task completed by one processor is now shared among multiple computing devices, cutting down on cost and time.

Role of OpenCL

OpenCL (Open Computing Language) is the programming language used to communicate with the computing devices available. The computing devices OpenCL supports are:

• CPUs (Central Processing Units)

• GPUs (Graphics Processing Units)

• DSPs (Digital Signal Processors)

• FPGAs (Field-Programmable Gate Arrays)

Through OpenCL, we communicate with these computing devices, allowing us to harness the computational power of heterogeneous computing.

Let's take a look at the architecture of OpenCL:

Application: It is the software program that uses parallel computation through OpenCL.

OpenCL framework: It is the interface layer used for communication between the application and the underlying hardware through libraries and APIs.

OpenCL runtime: It manages and executes parallel computations and handles tasks such as memory management, task scheduling, etc.

Device Driver: It is the bridge that helps the OpenCL runtime communicate with the hardware through low-level functionalities.

Accelerator hardware: It refers to all the hardware computational devices that are used to execute programs in parallel. 

Models of OpenCL

In OpenCL, different models explain the critical aspects of programming and execution. These models enable us to understand the significant key features in a simplified form. These models are stated below:

• Platform model

• Execution model

• Memory model

• Programming model 

This Answer will focus on the Platform model and its various components.

Platform model explained

Each model in openCL has multiple components, further breaking down the concepts of the individual model. Similarly, in the platform model, we’ll discuss its components.

Host

The OpenCL platform always originates from the host processor. The host processor refers to the main processor of the system, which is going to be managing the entire process of parallel computation. The functions that are under the responsibility of the host processor are listed below:

• Managing the operating system and the data transfer between the host and device

• Enabling device drivers

• Executing application host program

• Setting up the memory buffers

• Monitoring the status of system compute units

OpenCL runtime 

The OpenCL runtime is the logic layer on the OpenCL platform, playing the role of the translator. It is used to translate user commands to low-level commands, simplified to meet the needs of the specific device. Let’s take a look at an example. 

When using the clCreateBuffer API call for allocating a memory buffer, the responsibility of locating and the mechanism of accessing the specified memory buffer in the system go to the runtime library.

OpenCL devices

These are the computing devices the OpenCL platform uses to execute application programs in parallel. These include devices such as CPUs, GPUs, and DSPs.

Get ready to answer some questions and demonstrate your understanding.

Overview

In this Answer, we went over why we use heterogeneous computing, what OpenCL is, what it is used for, and the different models encapsulated in the OpenCL platform and focused on the OpenCL platform model.