How to Copy content from EGL Pixmap/Pbuffer to the screen


I have an OpenGL-ES app, where i am using EGL along with the opengl library. I want to render content on the screen through Pixmap surface/pbuffer surface.

I know that i can do it by creating an EGL window surface, render my content and then cann eglSwapBuffers after each frame.That is straight forward.

But because of some limitation, i want to do it using Pixmap surface/Pbuffer surface.Can any one please guide me.Is there a significant performance difference between the two approaches of Windows surface and pixmap/pbuffer surfaces?