In the User's Guide there is a whole section on CodeXL, with very interesting points. There is another debugger, opencl-emu, for which I know very little. Is it any good? How does it compare to CodeXL? Which one would be best to use?
BTW CodeXL 1.5 & 1.6 expect libGL under /usr/lib/fglr/dri, else they err. Easily fixed, by creating the directory and linking libGL, but it would be best to be fixed in the executable.