The GPUPerfAPI.2.11.564-lnx.tgz archive available here: http://developer.amd.com/tools-and-sdks/graphics-development/gpuperfapi/ does not include any headers in the "Include" directory. It also does not include documentation (user guide or license). There are no sample codes either. All that is included are two binary blobs libGPUPerfAPICL.so and libGPUPerfAPIGL.so. Although not impossible for clever hackers, the lack of headers makes it difficult to actually use this API.
It would be nice if the Linux GPUPerfAPI could get a little more love from AMD. Thank you.
Download Windows version. I think they will be working fine. Most likely AMD developers overlooked that Linux version is missing also user guide and license.