first ,we use 64-byte minimum frame size packets as the base
when only one direction traffic flows ,we will get this below:
more than 20Mpps every core can generate or receive,it's rather huge load.
with dual directions ,the pps a single core can gen/recv decreases .
~18Mpps, single core performance decrease a little ,total throughput rate does not increase linearly,we would say it's basing on memory ,and memory bandwidth for every core/socket is limited.
next we increase packets size to 1514.
still ,here is what single core can generate or receive:
about 2.4Mpps(30Gbps) for 1514 frame size .
also we expect single core gens/recvs a little less than one can can do , we verify it:
see,single core capability is about 1.2Mpps(15Gbps),almost halved.
4.5 smoketest
we will generate four virtual links ,two are assigned to socket 0 and another two are assigned to socket 1,here is the host eal command line :
virtual links on different sockets will not influence each other that much,here we get this throughpktgen> start 0,2 :
that's to say,only virtual links on the same socket can affect each other:
we get this through pktgen>start 0,1,2 :
At last ,we set frame size to 1514 and start all ports only in one direction:
note that we can achieve total 4.9Mpps(60Gbps).
next we start all ports with dual directions:
so far ,we know no matter how we arrange the layout of cpu and numa and virtual link ,the memory bandwidth limits the total throughput in the system. we are definitely sure about this from the following figure:total throughput of 64-byte frame:
so,we could be a little proud that virtual link bundles can handle almost 60Gbps packets flows of frames of any size.
4.6 summary
the bottleneck of vecring is absolutely memory bandwidth,same with virtio backed virtual link .
