Book Image

OpenCL Programming by Example

Book Image

OpenCL Programming by Example

Overview of this book

Research in parallel programming has been a mainstream topic for a decade, and will continue to be so for many decades to come. Many parallel programming standards and frameworks exist, but only take into account one type of hardware architecture. Today computing platforms come with many heterogeneous devices. OpenCL provides royalty free standard to program heterogeneous hardware. This guide offers you a compact coverage of all the major topics of OpenCL programming. It explains optimization techniques and strategies in-depth, using illustrative examples and also provides case studies from diverse fields. Beginners and advanced application developers will find this book very useful. Beginning with the discussion of the OpenCL models, this book explores their architectural view, programming interfaces and primitives. It slowly demystifies the process of identifying the data and task parallelism in diverse algorithms. It presents examples from different domains to show how the problems within different domains can be solved more efficiently using OpenCL. You will learn about parallel sorting, histogram generation, JPEG compression, linear and parabolic regression and k-nearest neighborhood, a clustering algorithm in pattern recognition. Following on from this, optimization strategies are explained with matrix multiplication examples. You will also learn how to do an interoperation of OpenGL and OpenCL. "OpenCL Programming by Example" explains OpenCL in the simplest possible language, which beginners will find it easy to understand. Developers and programmers from different domains who want to achieve acceleration for their applications will find this book very useful.
Table of Contents (18 chapters)
OpenCL Programming by Example
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

User-created events


All the events which we have discussed till now are all command queue created events. Applications may want to create user defined events, and use it to track the progress of different workloads given to different devices in an OpenCL context. The function for performing the same is as follows:

cl_event clCreateUserEvent (cl_context context,cl_int *errcode_ret)

The preceding function creates an user event object. Note that the user event created is per context. This means that each device in a context can wait on a user event to complete before the device command queue can execute next task. User-created events are useful for an application developer, in such a way that the developer can wait on this event in-order to reach a point of computation in his algorithm. An OpenCL algorithm may consist of many kernel tasks and data transfer operations. All user-created events reach a state of CL_SUBMIITTED first. They do not reach a state of CL_QUEUED since no task is queued to...