P4实现测量任务和sketch的思想

P4实现HLL
/* HLL SKETCH: https://research.neustar.biz/2012/10/25/sketch-of-the-day-hyperloglog-cornerstone-of-a-big-data-infrastructure/ */

// NOTE: instead of indexing the bitmap using the B lowest order bits and calculating the #zeroes as seen starting from bit B+1,
// We do the opposite:
// The B higher order bits are used to index and the zeroes run is calculated from the B+1 highest bit.
// Doing this way, the calculation of the length of the zeroes-run is easier using an LPM lookup with the TCAM

超点检测
count-min sketch + bitmap（CM sketch的每一个cell都用一个bitmap表示。最后通过查cell的bitmap的个数得到每一个srcIP的dstIP基数）