The Linux OpenCL support for Intel CPUs is not in as good shape as the Intel Windows OpenCL support at this time, but here are some benchmarks that explore the Intel Ivy Bridge OpenCL performance under Linux.
For OpenCL on Intel CPUs under Linux, there is the Intel OpenCL SDK that has long been available. This OpenCL SDK supports Sandy Bridge and Ivy Bridge CPUs with the IOC (Intel Offline Compiler) but this software package for doing OpenCL on the CPU is closed-source and only offered via Intel's web-site. The offered binary comes solely in the form of a 64-bit RPM, but the Red Hat package can be extracted and made to work on Ubuntu.
This Intel OpenCL SDK also does not support utilizing OpenCL on the graphics core under Linux (it seems to be compatible under Windows with Ivy Bridge), which is now a possibility with Ivy Bridge. Intel Open-Source Technology Center developers do appear to be dabbling with OpenCL on their Intel graphics core under Linux, but there is not any end-user support at this time and it is not clear how they plan to accomplish such GPGPU support. Intel is still backing their classic Mesa DRI driver where as the other open-source OpenCL enablement happening within the community is via a Gallium3D state tracker -- see Radeon Gallium3D OpenCL Is Coming Close and OpenCL Gallium3D State Tracker Merged Into Mesa. The benchmarks in this article are just of the Intel OpenCL SDK on some Sandy Bridge and Ivy Bridge processors. Additional information on the Intel 2012 OpenCL SDK is at software.intel.com.
Besides desiring Intel Linux GPGPU support in the future, it will also be nice when there's a proper open-source CPU-based OpenCL SDK implementation that can work its way upstream and then found by default in various Linux distributions. One possibility here is with the OpenCL/Clover Gallium3D state tracker on top of the LLVMpipe driver or there are also various other LLVM/Clang projects that have been coming about for OpenCL.