Testbench Controlled System Calls - Managing the SoC Verification Data Base

System calls are an effective way to control the behavior and outcome of a HDL simulation. Programming Language Interface (PLI) is a way to provide Application Program Interface (API) to the HDL. This mechanism is capable of invoking library functions (regardless to the programming language used, i.e: C/++, Java) from the HDL code itself. These functions are called system calls; they are very useful and can be used to control various simulation outputs such as coverage collection, dumping signals or variables etc. These system calls may be native to the simulation tool or custom designed for specific use. These system calls may have a major impact on the data base creation during HDL simulation and applying them discriminately in a large SoC project may have very serious implications. Just for an example, getting a full signal dump for every test in the SoC is a very costly task in means of storage, computing resources and simulation time. The solution to balancing between the system call adverse effects and benefits is to synchronize between them and the simulation itself.