[CentOS] Network performance issue on CentOS 6 KVM

Hi All,

I am using CentOS 6.4 on 4 servers, guests are also CentOS 6.4

Network is setup using virtio, and vhost, this works well but sometime I
see connection issue from application to DB.

I found that sometimes latency increases from 0.200 ms approx to 123ms or
even more sometimes, this happens only for 1-2 packets but keep happening
after sometime.

CPU load remains under 1, CPU usages is around 20-30%.

If I ping from host machine to host machine then there is consistent
latency, this only happens when ping from a guest machine to either other
guest machines or a host machine.

Did anyone face similar issue?