GL_SGIX_fragments_instrument
http://www.opengl.org/registry/specs/SGIX/fragments_instrument.txt
GL_SGIX_fragments_instrument

	GL_FRAGMENTS_INSTRUMENT_SGIX 0x8313
	GL_FRAGMENTS_INSTRUMENT_COUNTERS_SGIX 0x8314
	GL_FRAGMENTS_INSTRUMENT_MAX_SGIX 0x8315