The advent of multi-/many-core architectures demands efficient run-time supports to sustain parallel applications scalability. Synchronization mechanisms should be optimized in order to account for different scenarios, such as the interaction between threads executed on different cores as well as intra-core synchronization, i.e. involving threads executed on hardware contexts of the same core. In this perspective, we describe the design issues of two notable mechanisms for shared-memory parallel computations. We point out how specific architectural supports, like hardware cache coherence and core-to-core interconnection networks, make it possible to design optimized implementations of such mechanisms. In this paper we discuss experimental results on three representative architectures: a flagship Intel multi-core and two interesting network processors. The final result helps to untangle the complex implementation space of synchronization mechanisms.