Linux, with its vast arsenal of developer and Quality Assurance (QA) tools, has a really powerful one in perf(1). In a nutshell, the perf toolset is the modern way to perform CPU profiling on a Linux box. (Besides a few tips, we do not cover perf in detail in this book.)
Akin to the venerable top(1) utility, to get a thousand-foot view of what's eating the CPU (in a lot more detail than top(1)), the perf(1) set of utilities is excellent. Do note, though, that, quite unusually for an app, perf is tightly coupled with the kernel that it runs upon. It's important that you install the linux-tools-$(uname -r) package first. Also, the distribution package will not be available for the custom 5.4 kernel we have built; so, when using perf, I suggest you boot your guest VM with one of the standard (or distro) kernels, install the linux-tools-$(uname -r) package, and then try using perf. (Of course, you can always manually build perf from...