Part III Kernel monitoring #
- 4 SystemTap—filtering and analyzing system data
SystemTap provides a command line interface and a scripting language to examine the activities of a running Linux system, particularly the kernel, in fine detail. SystemTap scripts are written in the SystemTap scripting language, are then compiled to C-code kernel modules and inserted into the kerne…
- 5 Kernel probes
Kernel probes are a set of tools to collect Linux kernel debugging and performance information. Developers and system administrators usually use them either to debug the kernel, or to find system performance bottlenecks. The reported data can then be used to tune the system for better performance.
- 6 Hardware-based performance monitoring with Perf
Perf is an interface to access the performance monitoring unit (PMU) of a processor and to record and display software events such as page faults. It supports system-wide, per-thread, and KVM virtualization guest monitoring.
- 7 OProfile—system-wide profiler
OProfile is a profiler for dynamic program analysis. It investigates the behavior of a running program and gathers information. This information can be viewed and gives hints for further optimization.
It is not necessary to recompile or use wrapper libraries to use OProfile. Not even a kernel patch is needed. Usually, when profiling an application, a small overhead is expected, depending on the workload and sampling frequency.
- 8 Dynamic debug—kernel debugging messages
Dynamic debug is a powerful debugging feature in the Linux kernel that allows you to enable and disable debugging messages at runtime without the need to recompile the kernel or reboot the system.