2016-04-14 - docker networking performance

today Sławek pointer my attention to the fact, that networking is much slower inside docker containers, than it is on host… and indeed it is – almost by half!

the test scenario was simple. on host machine i've launched simple application, that generated ~2GB/s of pseudo-random garbage, that was piped though ncat to the other side. other side was:

• loopback interface (as a reference point)
• docker container started with own networking (default)
• docker container started with host's networking (–net=host option)

here are the results (average of 4 runs, 10GB transfer each):

it is clear now that host network should be used for network-sensitive applications. default (better separation at the cost of performance) is probably good for everything else. ;)