Profiling a Specific Process or Kernel Thread

You can invoke the er_kernel utility with one or more -T arguments to specify profiling for specific processes or threads:

• -T pid/ tid for a specific process and kernel-thread

• -T 0/ did for a specific pure-kernel thread

The target threads must have been created before you invoke the er_kernel utility for them.

When you give one or more -T arguments, an additional metric, labeled Kthr Time, is produced. Data is captured for all profiled threads, whether running on a CPU or not. Special single-frame call stacks are used for indicating the process is suspended (the function <SLEEPING>) or waiting for the CPU (the function <STALLED >).

Functions with high Kthr Time metrics, but low KCPU Cycles metrics, are functions that are spending a lot of time for the profiled threads waiting for some other events.