perf - Perf is a simple app monitoring solution paired with meaningful alerts.
Kcachegrind - Callgrind is a profiling tool and KCachegrind is able to visualize output of the profilers.
ftrace - A function tracer for the Linux kernel.
Valgrind - Valgrind is an instrumentation framework for building dynamic analysis tools.
strace - Trace system calls and signals. A diagnostic, debugging and instructional userspace utility.
dotMemory - dotMemory allows users to analyze memory usage in a variety of .NET and .NET Core applications.