how to show cpu usage on mac

System Resource Monitoring on macOS

macOS Activity Monitor

The primary utility for observing resource utilization. Located in the /Applications/Utilities/ directory, it provides a real-time overview of system performance.

Activity Monitor Tabs

  • CPU: Displays processor usage metrics for all processes and the system as a whole.
  • Memory: Illustrates memory pressure and allocation.
  • Energy: Provides insight into energy consumption by individual applications.
  • Disk: Tracks disk I/O activity.
  • Network: Monitors network throughput.

CPU Usage Metrics

The CPU tab within Activity Monitor presents several key metrics:

  • % User: The percentage of CPU time spent executing user-level code.
  • % System: The percentage of CPU time spent executing kernel-level code.
  • % Idle: The percentage of CPU time the processor is idle.
  • CPU Load: Reflects the average number of processes ready to run or running over a specific time period (1, 5, and 15 minutes). A load average of 1.0 indicates the system is fully utilized by a single core. Values exceeding the number of cores suggest potential performance bottlenecks.

Command-Line Tools

macOS offers command-line utilities for resource monitoring, suitable for scripting and terminal-based workflows.

top

A dynamic real-time view of running processes, ordered by CPU usage by default. Pressing 'H' toggles per-thread data.

Example:

top -o cpu

ps

Provides a snapshot of running processes. Useful for scripting and automation.

Example:

ps aux | head

vm_stat

Displays virtual memory statistics, including page faults and memory pressure. Can be used to indirectly assess CPU activity when memory is a bottleneck.

Example:

vm_stat

sysctl

Allows retrieving kernel variables related to system performance.

Example (getting CPU usage information):

sysctl vm.loadavg

Interpreting CPU Usage

High CPU usage can indicate a number of factors, including:

  • Resource-intensive applications.
  • Malware or background processes.
  • Insufficient system resources (RAM, disk speed).
  • Driver issues.

Persistent high CPU utilization warrants further investigation to identify the root cause and implement appropriate solutions.