Flame Graphs vs Tree Maps vs Sunburst (2017)(brendangregg.com) |
Flame Graphs vs Tree Maps vs Sunburst (2017)(brendangregg.com) |
This is how the old spacemonger app worked, and I liked it so much I had to recreate it for Linux/Mac: https://github.com/alanbernstein/treemonger. My version still needs some work, but it's minimally useable.
Flame graphs I have a love/hate relationship with. The hierarchy is very useful, but the name and coloring can be very confusing and misleading. Most people I show them to think red == something bad, but the color is actually just for aesthetics.
The source code got lost ages ago, but here are some screenshots of bookshelf graphs applied to SQL plan node level execution metrics:
https://tanelpoder.com/posts/sql-plan-flamegraph-loop-row-co...
Like, one just has to look at the qdirstat screenshot at https://github.com/shundhammer/qdirstat. On the bottom-right corner, there are visually distinct boxes of sub-boxes that guide the eye towards a logical set of files.
A while ago I was experimenting with interactive exploration of (huge) Monte Carlo Tree Search trees. Inspired by file system visualization tools, my first attempts were also tree maps and sunburst graphs, but I ran into the same problems as in the article.
I tried flamegraphs next with the following setup:
- The number of visits in each node maps to the width and order of each bar (i.e., the most visited node was first and was the largest)
- The expected value maps to the color of each bar.
And then it was a perfect fit: it's easy to see what's going on in each branch at the first levels, and the deeper levels can be explored through drilling down.
E.g.
Treemaps are indifferent to "unknown" or "unlabeled" nodes. Area is disk space.
Whereas the simple act of labelling a node adds another outer ring arc to the sunburst (thus more coloured area), even though the underlying truth hasn't changed.
Flamegraphs seem so much more interpretable and informative than the other plots there, at least to me personally. And I never would have thought to use them for this, because usually when I need to clean out disks or take care of storage it's time sensitive and I want to spend the minimum time figuring things out, and poor viz is enough to accomplish the goal.
An ongoing falmegraph of disk usage over time would be super helpful for many systems I'm working with right now.
In lieu of that, a flame graph is tolerable. The polar coordinate one is very pretty garbage. EDIT: Use it when you want to mislead people with a flashy graph.
This simple math fact is the reason why all grand hyperlink projects from 1960 to 2010 couldn't work, e.g. Xanadu.
Worse, in small examples with fewer than a hundred nodes it looks like it is a real improvement over linear text with jumps - we are after all now using _all_ the possible screen real estate.
Edit: I'll keep this up to share my embarrassment, but I missed entirely that the article was about disk space. I admit I only looked at the pictures haha.
Look at the example in the link and try to make sense of it.
One could drill down e.g. Groceries > Drinks > Coca-Cola if one is so inclined...