How do flame graphs handle the case where most of the time is spent in some leaf function that is called from all over the program? In this case, each individual stack would not take much time but in aggregate, a lot of time is spent in the function at the top of all of the call stacks. This should not be that uncommon to have hotspots in things like copying routines, compression, encryption etc that are not associated with any particular stack.
Although I guess a flat text profile of functions sorted by time would also highlight these kinds of hot spots. Still, if we want a single graphical view as a go-to, it's not clear that flame graphs are all that much better than pprof DAGs.
pprof from https://github.com/google/pprof can produce a DAG view of a profile where nodes are sized proportional to their cumulative time, e.g., https://slcjordan.github.io/images/pprof/graphviz.png and such a view would seem to cover the case above and subsume the usual use cases for a flame graph, would it not?
Although I guess a flat text profile of functions sorted by time would also highlight these kinds of hot spots. Still, if we want a single graphical view as a go-to, it's not clear that flame graphs are all that much better than pprof DAGs.