I am in the process of optimizing a single OpenCL C kernel for an AMD Radeon HD 7970 GPU (950MHz clock, 3 GB GDDR5 RAM) on a system with two Intel Xeon 6-Core hyper-threaded processors (~96 GB DDR3 RAM, ~3 TB HDD) running Ubuntu 12.04 LTS x86-64. I have used the CodeXL Profiler in the past to generate application trace and performance counter information to identify potential bottlenecks in my code. Recently, I updated from the 8.xxx AMD Catalyst Driver to the 13.xxx version, and installed the latest version of CodeXL from their website: (http://developer.amd.com/tools-and-sdks/heterogeneous-computing/codexl/#one) and noticed that the kernel occupancy percent is not displayed for my kernel. I am interested in generating the profiling graphs that estimate optimal workgroup size, register count, and other performance metrics based on performance counter traces to make informed optimization decisions. If anyone has encountered a similar problem and has a solution or may be able to assist in troubleshooting, I would appreciate any help.