Performance hit running in docker container

I have an application that I can run from Linux shell that reads a directory of files and then writes some results to another directory.

When I run this application from a bash shell inside a docker container, I am seeing a noticeable performance degrade.

Note I am mapping the input files and output directory using the -v option in the docker run command.

The time delta for this test is from 22 minutes not using docker to 26 minutes using docker.

Any ideas? Is there any expected performance hit? I could imagine some, but not to this degree.

Thanks,

Mabry