rbspy VS perf-map-agent

We used rbspy to generate the flamegraph:

You could use rbspy to profile the EventMachine process as it's doing the workload, and try to see there where most of the time is being spent.

Not sure what your issue is and you got some of this info from strace, but FYI rbspy can also help profile where a running Ruby process is spending its time: https://rbspy.github.io/. I think it's a little more helpful than strace in that it should bring it back to Ruby code rather than just showing the raw syscalls.

Even the most general profiler tool will show you each statement's accumulated time. These are called statistical profilers and give you a panoramic view of what the test is doing. An example of such a profiler is rbspy:

As a result, you need to craft a specific routine for each interpreter runtime (in some cases, each version of that runtime) to obtain symbol information. Educated eyes might have already noticed, it's not an easy undertaking considering the sheer amount of interpreted languages out there. For example, a very well known Ruby profiler, rbspy, generates code for reading internal structs of the Ruby runtime for each version.

For production, it depends on what the process is built with. There are possibly better tracing tools than just strace. For example Java has JMX, Go has pprof. There's also things like rbspy for Ruby.

I was a bit surprised to find out that the tool used to generate the flamegraph for Ruby (rbspy [1]) is written in Rust. lol

[1] https://github.com/rbspy/rbspy

Maybe https://github.com/rbspy/rbspy would allow you to profile the running ruby process handling web sockets?

c function is not very helpful to find the performance problem, so we dug deeper.

Is there a way to launch perf-map-agent's script perf-java-flames with a process executable instead of first launching the executable and then monitoring it's pid? By monitoring the pid, I think we are skipping some of the scripts launched at startup.

I don't know enough about wasm runtimes, but for example JIT runtimes like nodejs (or JVM via perf-map-agent [0]) allow writing out debug infos via the Linux Kernel JIT-Interface [1], which debuggers and profilers can then pick up to symbolize stack traces.

[0] https://github.com/jvm-profiling-tools/perf-map-agent

The runtimes usually don't enable providing symbol mappings by default. You might need to change a configuration, run the virtual machine with a specific flag/environment variable or run an additional program to obtain these mappings. For example, JVM needs an agent to provide supplemental symbol mapping files, called perf-map-agent.