The latency is not accurate

[abaowhy]

0、network latency
The network latency is around 0.15ms。

1、redis-cli latency
wanghaiyang@db-ck-1c-1:~$ redis-cli -h redis-bmk.uyffb3.ng.0001.apne1.cache.amazonaws.com --latency

2、memtier_benchmark result

memtier_benchmark -s redis-bmk.uyffb3.ng.0001.apne1.cache.amazonaws.com -t 2 -c 5 --ratio=1:6 --test-time=120 --select-db=0 --hide-histogram -x 3 --expiry-range=60-90 --data-size=384

The latency of memtier_benchmark is less than redis-cli latency and network latency，why？