Great question! I actually just touched on this in another thread that went up right around the same time you asked this. It is clearly the next big frontier!
The short answer is: It's something I'm actively thinking about, but instrumenting micro-level events (like ZGC's load barriers or G1's write barriers) directly inside application threads without destroying throughput (or creating observer effects invalidating the measurements) is incredibly difficult.
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Great question! I actually just touched on this in another thread that went up right around the same time you asked this. It is clearly the next big frontier!
The short answer is: It's something I'm actively thinking about, but instrumenting micro-level events (like ZGC's load barriers or G1's write barriers) directly inside application threads without destroying throughput (or creating observer effects invalidating the measurements) is incredibly difficult.