GammaRay

This is another specialized tool coming from KDAB, a German company specializing in Qt. It is not so much a profiler, as an application inspector, allowing a peek into the object structure of a running application. But because performance optimization sometimes amounts to finding excess resources, such a tool also has a place in your quiver! Qt Creator even has built-in integration for GammaRay; unfortunately, it's only available in Qt Automotive Suite.