specman - How to reduce the overhead of emitting an event from DPI?

Question

I’m using e coverage for sampling signals in my DUT. In order to sample the covergroup, I’m emitting the coverage sample event inside a DPI code (defined in c interface of e, called in my hdl code). But it seems like when emitting this event there is a lot of overhead which is not related to the coverage collection. What can I do in-order to reduce this overhead?

Answer 1

尝试在 e 中定义、发出和处理所有覆盖组和事件。这样你就不会得到语言之间转换的开销。

Answer 2

不要发出事件，而是使用 API 对事件进行程序采样 (covers.sample_cg()) 例如，如果您有一个名为 cg1 的覆盖组，定义在类型 t1 中，并且您想对 t1 的 t1_inst 进行采样，然后代替调用：

emit t1_inst.cg;

称呼 ：

covers.sample_cg(“t1.cg1”, t1_inst);

Answer 3

您应该定义与所需信号更相关的事件。您还可以在总线更改的特定位上定义事件。