Performance flying is a Wingsuit Skydiving discipline which uses GPS to measure the performance that is being achieved during a flight. The graph above is produced by taking data from a FlySight GPS which is worn inside a jumper's pocket or helmet and pulled into a piece of software called ParaLog,
In the example above you can see from the red line that the jumper exited the aircraft at 14,500ft and pulled at 4,000ft. The green line shows that the jumper flew 4 miles in 2 minutes and 45 seconds. The turquoise line shows that the jumper's horizontal speed peaked at 107mph and the dark green line plots the 3D (diagonal) speed of the suit, which reached 113mph. The blue line shows that the jumper was falling at 35-40mph throughout the jump and the grey line shows that the glide ratio (feet travelled forward for each foot fallen) moved between around 1.25:1 and 2.75:1.
The blue window between 6500ft and 9700ft shows the competition window. During a competition a jumper is required to achieve the maximum possible time or forward speed or lowest possible descent rate within this window. The jumper will know which of these three variables they are required to target before each jump. Generally, poor results will be seen outside of the competition window as the competitor attempts to dive the suit to build speed leading into the window and stall the suit when exiting the window.
To understand dive and stalls think of a bird trying to glide: in order to build up speed it will dive vertically, and will convert this vertical speed into horizontal speed in order to glide. If the bird does not flap its wings and continues to glide horizontally, then eventually it will burn off its forward speed and will stall (fall out of the sky). Because a wingsuiter cannot flap their wings to create lift, they would need to dive the suit again in order to get it flying following a stall.