number of polys

how can i know the number of polygons being rendered each frame ??

well you render them ? so you should know how many

if you use vertex arrays, count would be
for triangles: indices count / 3
for triangle strip: indices count - 2
for quads: indices count / 2

if it’s not your code rendering it, you would need some tool that intercepts gl calls, GLintercept is such a tool.