Hello, While looking into Flink internals, I've noticed that there is already a mechanism for stack-trace sampling of a particular job vertex.
I think it may be really useful to allow user to easily render a cpu flamegraph <http://www.brendangregg.com/flamegraphs.html> in a new UI for a selected vertex (new tab next to back pressure) of a running job. Back pressure tab already provides a good idea of which vertex causes trouble, but it's hard to say what's actually going on. I've tried to implement a basic REST endpoint <https://github.com/dmvk/flink/commit/716231822d2fe99004895cdd0a365560479445b9>, that prepares data for the flame graph rendering and it seems to be providing good insight. It should be straightforward to render data from the endpoint in new UI using existing <https://github.com/spiermar/d3-flame-graph> javascript libraries. WDYT? Is this worth pushing forward? D.
