在CPPI_QMSS_LLD_SDS.pdf 的26页 有如下一段，在multicore navigator user guide 文档中4-37页也有类似的如图所示，不太明白这几中触法模式，请大家帮我解答一下。
The available interrupt pacing modes are based on one of the following events:
• Programmable delay since last interrupt to the host
• Programmable delay since first packet on new activity
• Programmable delay since last packet on new activity
