Flame graph: color by groupings

[roji]

Perfview already has excellent support for grouping (GroupPats), it really seems useful for flame graphs to color stack frames based on groups.

[brianrob]

cc: @adamsitnik

[adamsitnik]

I am afraid that I won't have the time to implement it anytime soon. The best I can do is to provide some hints for contributors who would be interested in implementing that:

The Model is built here and most probably CallTreeNode contains information about grouping. Then the colors are generated here and selected here.

I've not spent too much time thinking about it, but you should be able to extend the selection of the color to use information from CallTreeNode.

Additional requirements that need to be kept in mind:

• some users open multiple GB trace files and they still want us to draw the FlameGraph quickly. So it would be good to have 2-3 GB trace file and see how long it takes to draw the FlameGraph before and after the changes
• grouping can be disabled, this should fall back to current coloring

[brianrob]

Thanks @adamsitnik. Appreciate the input. I'll keep this around in case folks want to contribute to this work.