NvOSD_LineParams poor performance

Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU) V100
• DeepStream Version 6.0
• JetPack Version (valid for Jetson only)
• TensorRT Version
• NVIDIA GPU Driver Version (valid for GPU only)
• Issue Type( questions, new requirements, bugs)
• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)
• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)

I am currently working with Deepstream for object detection and object tracking.
I use Gst-nvdsosd to draws bounding boxes. I run 10 camera streams, fps each camera stream is about 24-25fps. But when I use NvOSD_LineParams to draw polygon lines, the fps drops from 24-25fps to 16-17fps.
Can anyone help me?

Image when not use


Can you check the CPU usage?

Here about cpu usage, I see no difference

Image when not use

Image when use NvOSD_LineParams to draw polygon