Delays with Matlab/Simulink/Python

Hi all!

I have next problem and I will be glad if someone can give me a right way! My Simulink model use Workspace data and renew data in Workspace in its turn. Outer Python program send and get data to Workspace too with Matlab.engine. So I have connected Python with Simulink via Matlab Workspace. In Simulink Model real-time block is used (Real-Time Pacer). If there is no connect Python-Simulink, everything is great, but when it is on, Simulink has delays, so it becomes even no quasi real-time. How can I avoid this delays?