[brendangregg]

The origin problem for flame graphs was MySQL server performance involving dozens of threads: as a timeline view you need dozens of timelines, one for each thread, since if you render it on one (I know this is probably obvious) then you have samples from different threads from one moment to the next turning the visualization into hair. Flame graphs scale forever and always show the aggregate: any number of threads, servers, microservices, etc.

I think great UI should do both: have a toggle for switching between flame graphs (the summary) and timelines (aka "flame charts") for analyzing time-based patterns. I've encouraged this before and now some do provide that toggle, like Firefox's profiler (Flame Graphs and Stack Charts for timeline view).

As for 20ms, yes, we do want to take it down. A previous HN comment from years ago, when I first published FlameScope, was to put a game frame on the y-axis instead of 1 second, so now each column shows the rendering of a game frame, and you can see time-offset patterns across the frames (better than a time-series timeline). We started work on it and I was hoping to include it in this post. Maybe next one.

[forrestthewoods]

I’ve never actually seen a profiler that shows quite what I want. I have lots of subsystems running at different rates. Gameplay at 30Hz, visual render at 90Hz, physics at 200Hz, audio at some rate, network, some device, etc.

So what I want is the ability to view each subsystem in a manner that lets me see when it didn’t hit its update rate. I have many many different frame rates I care about hitting.

Of course things even get more complex when you have all the work broadly distributed with a job system…