Intel® SDK for OpenCL* Applications 2012 Release Notes

Intel® SDK for OpenCL* Applications 2012* Release Notes contain information about the Intel® SDK for OpenCL* Applications 2012 new features, fixed bugs, and includes the updated list of supported hardware and software. It also includes information on SDK limitations and known issues.

3rd Generation Intel® Core™ processor family supports the OpenCL* 1.1 standard across both CPU and the Intel® HD Graphics directly through the Intel® HD Graphics driver on the Microsoft Window* 7 operating systems.

For the OpenCL* support on previous generations of the Intel® Core™ processors and the Intel® Xeon® processors, and for Linux* operating systems, the CPU only runtime package is available either directly through the Intel® SDK for OpenCL* Applications 2012 or by downloading the Intel® SDK for OpenCL* - CPU only runtime package 2012.

Table of Contents

• New in this Release
  • Intel® HD Graphics Support
  • OpenCL* Extensions Support
  • Intel® SDK for OpenCL* Applications Development Tools
  • OpenCL* Sample Code
• Technical Requirements
• Product Limitations and Known Issues
  • CPU Device Limitations
  • Intel® HD Graphics Device Limitations

New in this Release (Intel® SDK for OpenCL* Applications 2012)

Intel® HD Graphics Support

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• Intel® SDK for OpenCL* Applications now supports OpenCL* 1.1 on the 3rd Generation Intel® Core™ processor family.
• This release supports a single OpenCL* platform to seamlessly access the compute power across both Intel® Architecture CPU and Intel® HD Graphics devices.
• OpenCL* support on the 3rd Generation Intel® Core™ Processors with the Intel® HD Graphics 4000/2500 is seamlessly available with the Intel® HD Graphics Driver on both CPU and the Intel® HD Graphics.
• OpenCL* platform consists of two OpenCL* devices:
  • Intel® Architecture CPU
  • Intel® HD Graphics (GPU)

Intel platform for the Intel® Xeon® processors or for previous generations of the Intel® Core™ processors includes only the CPU device.

OpenCL* Extensions Support

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Intel® SDK for OpenCL* Applications Development Tools

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Intel® SDK for OpenCL* Applications provides a comprehensive environment for build, debug, and tune stages of the OpenCL* applications development.

Intel® SDK for OpenCL* Applications comprises:

• Intel® SDK for OpenCL* - Debugger: Support OpenCL* kernel debugging on the Intel® Architecture CPUs.
• Intel® SDK for OpenCL* - Offline Compiler: Support OpenCL* kernel development and offline build across both CPU and the Intel® HD Graphics.

This SDK also provides profiling and tuning of OpenCL* applications through Intel® Graphics Performance Analyzers (Intel® GPA) and Intel® VTune™ Amplifier XE.

New in this release:

• Intel® SDK for OpenCL* Applications 2012 supports the Microsoft Visual Studio* 2010 in addition to the Microsoft Visual Studio* 2008.
• Intel® SDK for OpenCL* - Offline Compiler plug-in for the Microsoft Visual Studio*. This plug-in supports:
  • New project templates
  • Syntax highlighting
  • Auto-completion for types and functions
  • Offline compilation and build of OpenCL* kernels
  • LLVM code view
  • Assembly code view
  • program IR generation
  • Selection of target OpenCL* device - CPU or GPU.
• You can choose the target device (CPU or the Intel® HD Graphics) in the standalone version of the Intel® SDK for OpenCL* - Offline Compiler.
• Intel® SDK for OpenCL* - Debugger plug-in support for the Microsoft Visual Studio* 2010

OpenCL* Sample Code

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• Samples are available for both Microsoft Visual Studio* 2008 and 2010 versions.
• Each sample is now available for independent downloads at the SDK for OpenCL* Application Code Samples page.
• The following samples are added:
  • intel_ocl_resource_sharing (DirectX* 10 and media sharing interoperability)
  • intel_ocl_tone_mapping_multi_device (CPU + Intel® HD Graphics)
• Intel® Media SDK interoperability sample is updated to work entirely on the Intel® HD Graphics (OpenCL* and Intel® Media SDK interoperability)

Resolved Issues

Issues resolved since the Intel® OpenCL* SDK 1.5

• Performance issue when using small work-group size.
• High variance in performance when using the CPU device on Linux* OS.
• Fixed issue in enum types compilation.
• Fixed issue in conversion of float3 to float4.
• Fixed issues when using the Inte® VTune™ Amplifier XE 2011 software with an OpenCL* application.

Technical Requirements

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Intel® SDK for OpenCL* Applications 2012 introduces support for the 3rd Generation Intel® Core™ processor family.

Intel® Processors Support Matrix

Supported Operating Systems

Intel® SDK for OpenCL* Applications 2012 supports the following operating systems:

• Microsoft Windows 7* (32-bit version)
• Microsoft Windows 7* (64-bit version)
• Microsoft Windows 7* Service Pack 1 (32-bit version)
• Microsoft Windows 7* Service Pack 1 (64-bit version)
• Microsoft Windows Vista* Service Pack 2 (32-bit version)
• Microsoft Windows Vista* Service Pack 2 (64-bit version)
• Microsoft Windows Server 2008 R2
• Novell* SUSE* Linux Enterprise Server 11 Service Pack 1 (64-bit version)
• Red Hat* Enterprise Linux 6.1 (64-bit version)

Use the Microsoft Windows 7* Service Pack 1 to achieve better performance on the 2nd and the 3rd Generation Intel® Core™ processors.

Due to several Intel® AVX issues in the default glibc 2.11.1 implementation, the Intel® SDK for OpenCL* Applications libraries for 64-bit Linux* OS have the following requirements:

• SuSE Linux Enterprise Server 11, SP1 OS requires glibc-2.11.1-0.32.1
• For RedHat Enterprise Linux 6 OS requires glibc-2.12-1.47 (See also: http://rhn.redhat.com/errata/RHSA-2011-1526.html)

If you use a CPU that is not AVX-enabled, the patch might not be required.

Product Limitations and Known Issues

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• Before installing the Intel® SDK for OpenCL* 2012 on Windows* OS running on processors that do not include the OpenCL* support for the Intel® HD Graphics, make sure you deleted the following files from your system:
  • C:\Windows\System32\IntelOpenCL32.dll - on 32-bit OS
  • C:\Windows\System32\IntelOpenCL64.dll - on 64-bit OS
  • C:\Windows\SYSWOW64\IntelOpenCL32.dll - on 64-bit OS
• Linux* operating systems support only 64-bit applications.
• Media Sharing extension has been validated on Windows7* OS only.
• To overcome shared context (the OpenCL* context which includes both CPU and GPU devices) limitations:
  • Do not trigger for both devices (specify NULL as device_list parameter)
  • Avoid using images with CL_MEM_USE_HOST_PTR flag.
  • Avoid using on systems with discrete graphics.
  • Avoid calling clEnqueueMapBuffer[Image] on one device while calling clEnqueueUnmapMemObject on the other device (while this is enabled by the specification).
  • Use image formats supported by both devices only.
• Compilation support for the Intel® Advanced Vector Extension (AVX) instruction set architecture works on the 3rd Generation Intel® Core™ Processors.
• Intel® SDK for OpenCL* - Offline Compiler GUI is not supported on the 2nd Generation Intel® Core™ Processors running Red Hat Enterprise* Linux* 6 operating systems.


NOTE:
To work with the Intel® SDK for OpenCL* - Offline Compiler plug-in on 64-bit OS, you must configure the Visual Studio* for 64-bit applications (64-bit compiler and tools).


• If the Offline Compiler does not work, make sure that Java* runtime is properly installed on your system:
  • If JAVA_HOME environment variable exists, make sure that it contains the right path to the java library.
  • Add the path to the java bin library:
    • If JAVA_HOME exists, add %JAVA_HOME%\bin to the Path environment variable.
    • If JAVA_HOME does not exist add the full path to the java bin library.
  • Remove any other java paths (other java versions) from the Path environment variable.
• Interoperability with the Intel® GPA is supported only for the Microsoft Windows* operating systems.
• Microsoft Windows* Remote desktop does not work for the Intel® GPA interoperability.
• Intel® SDK for OpenCL* Applications supports the Intel® VTune™ Amplifier XE 2011 update 3 or higher.
• Intel® SDK for OpenCL* - Debugger does not support:
  • Disassembly view
  • Edit and continue capability
  • Multithreaded debugging
  • Two instances of visual studio running simultaneously

Installer

You may encounter the following error message while installing the software required for the Intel® SDK for OpenCL* Applications 2012 functionality:
"Setup has detected that the publisher of file cannot be verified".
To fix the problem, download and install the latest update for Root Certificates from the Microsoft* website (windowsupdate.microsoft.com), then try to install the SDK again.

CPU Device Limitations

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Run Time

• The calling convention of the Native Kernel user_func parameter for clEnqueueNativeKernel, has changed to "CL_CALLBACK" keyword. This change is according to the OpenCL* 1.1 specification.
• Setting affinity for the main thread before initializing the OpenCL* library may cause unpredictable results on Linux* operating systems. Create the OpenCL* context first if you want to set the affinity for your master thread.
• On Linux* operating systems the application thread should not exit while the OpenCL* commands are still being execute, otherwise it may cause undefined behavior.
• Call clFinish on a queue from the same thread you called clFlush for that queue to avoid performance loss.
• Avoid creating multiple command queues on the same sub-device. Scheduling between multiple command queues on the sub-device level is depth-first.
• The following scenarios are not supported by cl_ext_device_fission extension:
  • Calling clCreateSubdevicesEXT simultaneously with other OpenCL* calls by use of multithreading.
  • Calling clCreateSubdevicesEXT while a build is in progress, by use of multithreading or via an asynchronous build call.
  • Calling any of the fission APIs from within a callback, by use of clSetEventCallback, a build callback, an error reporting function, and clEnqueueNativeTask.
  • Dynamically creating and releasing devices currently refers to the existing OpenCL* context. Before creating any contexts you should divide the devices as required.
• After GFX driver was installed and then removed, CPU Bundle (the OpenCL* CPU Runtime) does not work. To fix the issue, remove the following files:
  On 64-bit version of Windows* OS:
  
  • C:\Windows\System32\igdbcl64.dll
  • C:\Windows\System32\igdfcl64.dll
  • C:\Windows\System32\igdrcl64.dll
  • C:\Windows\SysWOW64\igdbcl32.dll
  • C:\Windows\SysWOW64\igdfcl32.dll
  • C:\Windows\SysWOW64\igdrcl32.dll
  On 32-bit version of Windows* OS:
  
  • C:\Windows\System32\igdbcl32.dll
  • C:\Windows\System32\igdfcl32.dll
  • C:\Windows\System32\igdrcl32.dll

Language

• clCreateKernel crashes if the name of the kernel does not appear in program source code.
• The compiler incorrectly accepts initialized and non-function scope local variables as reported at the Intel® SDK for OpenCL* Applications forum.
• printf has a limit of 1024 characters per single % conversion.

Intel® HD Graphics Device Limitations

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• Intel® HD Graphics supports OpenCL* only on the 3rd Generation Intel® Core™ Processors with the Intel® HD Graphics 4000/2500.
• Intel® HD Graphics is supported only on the Microsoft Windows* 7 operating systems.
• For details on known issues with the OpenCL* standard on the Intel® HD Graphics, refer to the relevant driver release notes. Use the Intel® Driver Update Utility to identify your Intel® HD Graphics and to obtain the latest version of driver and release notes.

For more complete information about compiler optimizations, see our Optimization Notice.