explanation about tmm usage

Hi Satoshino , 
first you need to read about Hyper threading feature in F5 : 
https://my.f5.com/manage/s/article/K23505424
https://my.f5.com/manage/s/article/K15003 

then >> your guest runs over 2 cores devided into 4 hyper-threads based on vCPU that you have assigned  while configuring this guest. 
I see slot 1 >> ( tmm1.0 & tmm1.2 ) you can imagine it as ( tmm0.0 & tmm0.2) based on the slots. 

> For traffic I see traffic is balanced over the two tmm instances without issues.

your question : I undestood that core 0 and 2 are assigned for data plane, and that every core has two tmm processes, the first is the main process while the second is used only during spikes of traffic, am i right? 

> Not exactly right , you need to consider hyper-thread design , and know how it works then you can understand this mechanism.