It will be (kind of) interactive (e.g. http://lelf.lu/files/pandoc.svg) .

TL;DR (and the only one available) guide:

some-program +RTS -P
wget https://github.com/brendangregg/FlameGraph/raw/master/flamegraph.pl
chmod +x flamegraph.pl
flamingra some-program.prof | ./flamegraph.pl > picturesque.svg

Usage:

flamingra out.prof | …

or

… | flamingra | …

where out.prof is -P profiling output.