Hello, I'm new to DPDK

I've tried to run samples and got a query about core affinity.
As I understand, if a lcore has affinity to a CPU set, it will run only on the CPU set.
And I thought If I run a dpdk sample with core 0-2, none process can use the core (0-2). but when I try to run a simple app(not dpdk app) with taskset command, it runs on 0, 1, 2 cores.. 

what I want was if I use cores for dpdk apps none other process can access the cores.. but it seems possible.. 

I've googled to find out this but I couldn't find anything I wanted.
Is there anyone can explain about this...?


BR.
Jaehong Lee