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Does tlm_quantumkeeper::set_global_quantum affect Fast Models?

Oscar Huang

It's not clear to me how Fast Models, especially the ARM CPU models set or use quantums. If I call tlm_quantumkeeper::set_global_quantum in my sc_main to set a global quantum, will it also affect the exported virtual system called in my simulation application? If yes, is there any requirement on the size of the global quantum?

Thanks

-Oscar

  • +1

    The Fast Models use the tlm_global_quantum API to set and manage the quantum size; an example of using this API to set quantum size in an exported virtual system model:

        /* Number of ticks to simulate per quantum */
        double quantum = 10000.0;
        /* Simulation quantum, i.e. seconds to run per quantum */
        tlm::tlm_global_quantum::instance().set(sc_core::sc_time(quantum / 100000000, sc_core::SC_SEC));

    tlm_quantumkeeper is a utility class built on the tlm_global_quantum API, so it should function as intended within an EVS model.

    The recommended quantum size will depend on your workload and platform, for reference the EVS models use a default quantum size of 10000 nanoseconds. A higher quantum value will increase performance at the cost of accuracy and synchronization latency.