Feature Request: Support for 1000s of logs

I'm really enjoying tensorboard, it makes my life a lot easier and gives me a good idea of what's happening as training progresses.

Unfortunately, I've found one area of weakness shows up when many runs accumulate, because tensorboard starts to become very sluggish. Here is a video from a 22 core xenon workstation with 48GB ram and about 50% of resources free trying to display about ~250 runs in tensorboard, each with a single time step (epoch):

What would help:

• fix for performance issues when there are 1000s of logs
• a "view summary" button was added to the chart with a non-hover version of the hover data so we can see all of it
  • have a way to view, sort, copy and save that whole list of results that shows up when you hover
• Add a way write and view dictionaries of data mapping from strings to a mix of integers, strings, and floats which are associated with each run.
  • In my case it would be hyperparameters, others would likely have their own uses.
  • perhaps this last item already exists and I missed it?

Thanks for your consideration!

The issue names no files, tests, or entry points, so the relevant TensorBoard performance and chart code would first need to be located. Done would require addressing large-run performance and defining support for viewing, sorting, copying, saving, and associating per-run dictionary data.