As Thilo suggested, I believe what you're seeing are not multiple processes but threads. Linux' top
by default shows individual threads and their usages.
The htop
tool (apt-get install htop
) has the ability to hide these "Userland threads" and group the resource usage back into a single entry per process.
> htop
> F2 to open options
> Display options
> Hide userland threads (space to toggle)
> F10, Esc or q to return to display