Docker removes resource restrictions

  docker, question

At present, I am running a computing project, which needs some environment dependence, including compilation and so on. It is not easy to deploy, so I tried to use docker encapsulation, but encountered some problems.
When using the host computer to run the project, it can use 100 megabytes of bandwidth (20MB/s), but the mirror image running in the docker usually has a speed of less than 100 megabytes (6-10MB/s)
At the same time, the utilization rate of cpu has also decreased. when the host runs, it is not a problem to eat fully, but when the doc runs, it can only use 70%~80% of the utilization rate.
Is this docker’s default resource limit? How did this restriction be lifted

docker run
–cpu-shares …