I have used Epoch[0] and Rickshaw[1] before for similar purposes, and have heard that Plotly works well too (especially if the process that is generating the data is Python-based). For simple line charts, maybe Smoothie[2]?

Currently, I am trying to make a dashboard for visualizing many different data sources with WebSockets and Chartjs but it's still not quite ideal-- there's a bit of lag, and sending too much data via JSON really slows things down. If anyone has solved that this problem I would appreciate it if they told me how they did it.

0. http://epochjs.github.io/epoch/

1. http://code.shutterstock.com/rickshaw/

2. http://smoothiecharts.org/

Plotly animations are coming along gradually, and Reactive Vega may be something to look at. Unrelated to these, I've been exploring real-time visualizations (and more in focus, real-time configurability) with D3 e.g. here: http://bl.ocks.org/monfera/35be5626a47110312c35 but Mike Bostock and many of others have technical notes on updating charts, like here: https://bost.ocks.org/mike/path/

I'm using Flot for https://podium.live, 10-20 charts with upwards of 1k points/chart updating at 10hz. It can work, but you need to do a few things like wrapping things in requestAnimationframe and not redrawing axes.

That's an area I'm not an expert on (Though learning). C3/nvd3 support real-time updates, but Chart.js seems more maintained.