[yxhuvud]

> As I understand it, flame graphs add to normal x-axis-as-time ones by merging repeated calls to the same function, so if one function is called a lot it shows up as one wide chunk and not many small chunks spread out.

Not if the graph is sorted on time axis. Not if the callstacks look different in different cases. Not if the program is recursive and thus have different depth all over the place. There is a lot of places that merging can fall over and not happen.

[sgerenser]

If you sort it on a time axis, its not really a flame graph any more. The whole point of a flame graph is to group same stacks together, even if they happen at multiple disparate times.