function::task_cpu - Linux

Overview

function::task_cpu gathers CPU usage information for each thread that is currently mapped to the current group of logical cores. This is particularly useful for debugging CPU affinity-related issues or determining which tasks are consuming the most CPU time.

Syntax

function task_cpu <pid>

Options/Flags

• pid:

  The process ID (PID) of the target process. If no PID is specified, the function will display information about all threads in the current process.

Examples

Example 1: Display CPU usage for all threads in the current process:

function::task_cpu

Example 2: Display CPU usage for a specific thread with PID 1234:

function::task_cpu 1234

Example 3: Use task_cpu with top to identify the most CPU-intensive threads:

top -H -p $(function::task_cpu)

Common Issues

• "Process does not exist": Ensure that the specified PID is valid and that the process is still running.
• "Permission denied": Make sure you have root privileges to run the command.

Integration

function::task_cpu can be integrated with other Linux commands for advanced troubleshooting and monitoring scenarios. For instance:

Example 4: Combine task_cpu with taskset to change thread CPU affinity:

taskset -p 0x1 $(function::task_cpu)

Example 5: Use task_cpu with ps to display process and thread information:

ps -p $(function::task_cpu) -o comm,tid,time,cpu

Related Commands

• perf: A more advanced tool for performance profiling and analysis.
• cpulimit: A utility to control CPU usage for specified processes or threads.
• schedtool: A command to manage process scheduling parameters, including CPU affinity.