There is one interpreter for python 2.7 and one for 3.6. but just one process.
Depending on what you are doing there are ways to keep draw quick:
Drawing an image may be faster than stroking hundreds of paths. You can render static things to an ImageContext, then later draw that inside draw. For instance omz's sketch example does that every touch_ended.
For framebuffer type access, see the recent thread which dealt with both some real time audio generation and IOSurfaceWrapper enabling some low level image pixel manipulation and display