Symfony twig需要20秒才能渲染

I'm using symfony 2.6 on mac with built in web server of symfony. Loading pages takes very long time, some times. I checked symfony profiler and and saw that rendering twig is my problem, but i don't know why.

Another thing, when i disconnect my mac from internet, page load speed will be okay (1000ms). What's wrong in my project ?

(i have just 3 external js file in template and test my project with wget but same result)