LibreOffice converting as service Performance Issue

I have created a Service which accepts .rtf file and converts it to .pdf and sends it back.

I have used following two solutions,

  1. Calling it Directly
    sh /opt/libreoffice5.0/program/soffice --headless --convert-to pdf /opt/libreoffice5.0/program/sample.rtf

  2. Start Libre as a service and making a call by unoconv
    i. soffice --nologo --headless --nofirststartwizard --accept=‘socket,host=127.0.0.1,port=2220,tcpNoDelay=1;urp’
    ii. unoconv --connection ‘socket,host=127.0.0.1,port=2220,tcpNoDelay=1;urp;StarOffice.ComponentContext’ -f pdf <filename.rtf>

but none of them is performing well as a Web Service.
LibreService gets crashed after 5 concurrent Requests.
I want to Optimize it at least upto 50.

Thnak You.

RFO