Producing proper Flame Charts

[FlorentP42]

Context

So as I saw in the documentation there is a --flamechart option in this script supposed to produce Flame Charts (ordered by time) and not Flame Graphs (ordered alphabetically).

I made a few attempts at using it working with a folded file from a perf output on a single process, and failed, which led me to many questions:

Question 1

When I used the --flamechart option I got the exact same output as without this option... Is it actually implemented and working?

Question 2

Then I checked the format of the folded file and it does not look like there is any duplicate stack lines in here, and I am pretty sure I have the same code sections called at different times during the execution I recorded... How is a Flame Chart supposed to be properly generated with this as an input file? Shouldn't there be another format dedicated to that?

Question 3

I couldn't seem to find any information relative to threads in the folded file format either... Is there any way to generate one folded file per thread from a perf output? Or somehow separate the data in the file per-thread so that they are represented separately in the generated Flame Chart?

Question 4

I would assume a Flame Chart produced from a dedicated file format including timestamps would produce both a On-CPU and Off-CPU view as the timestamp let you see when a thead is "stuck" in some function and for how long, even if said function is a sleep, a mutex or an IO operation for example. Am I wrong with this assumption?