How to plot data while it's being processed
You can plot the data as it is being processed, but there's a couple of issues that come along with it in terms of efficiency.

Gnuplot needs to do work each time to process your data
Gnuplot needs to wait for your operating system to paint your screen whenever it updates
Your program needs to wait for Gnuplot to do any of this in order to go to the next step

All of these will greatly impact the amount of time you spend waiting for your data. You could potentially have it run every x iterations (eg. every 5 iterations), but even this wouldn't give you much of a speed-up.
I'm in the process of converting a large (several GBs) bin file to csv format using Python so the resulting data can be plotted. I'm doing this conversion because the bin file is not in a format that a plotting tool/module could understand, so there needs to be some decoding/translation. Right now it seems like Gnuplot is the way to go for such large data size.
I'm wondering if instead of waiting for the whole file to finish converting and then running Gnuplot, is there a way to plot the data as it's being processed? Perhaps I could bypass the csv file altogether.
Everything I've read so far points to plotting a file with data, but I have not seen any ways of plotting/appending individual data points.