Analyse thread dump: Perfomance trouble shot EAP7

Hi,
Have some performance trouble with exo5 eap7.1
we use the ajp listener with the default configuration

we test with jmeter, we send about 600 parrallel request, but that is very slow, it seems like some requests are bloqued, or wait for something.

I need your help please to analyse a thread dump generated with the jstack script.

Thank you very much for your reply,