The CPU_ALLOC_SIZE command is a performance monitoring tool that displays the allocation size (in kilobytes) for each active CPU on the system. It provides insight into how memory is being utilized by the CPUs and can help identify potential bottlenecks or areas where optimization might be beneficial.


CPU_ALLOC_SIZE [options]


  • -a, –all: Display allocation size information for all active CPUs.
  • -c, –cpu [CPU_ID] Specify the CPU ID for which to display allocation size information.
  • -h, –help: Display help and usage information.


Display allocation size information for all active CPUs:


Display allocation size information for CPU with ID 3:


Common Issues

  • Missing or incorrect CPU ID: Ensure that the specified CPU ID is valid and corresponds to an active CPU on the system.
  • Permission denied: Verify that the user has sufficient privileges to run the command.


CPU_ALLOC_SIZE can be integrated into scripts or command chains to monitor memory allocation over time or to trigger alerts based on thresholds. For example, the following script combines CPU_ALLOC_SIZE and watch to continuously monitor memory allocation for CPU 1:

watch -d CPU_ALLOC_SIZE -c 1

Related Commands

  • vmstat: Provides detailed memory statistics, including CPU allocation information.
  • pidstat: Monitors memory usage and other metrics for specific processes.
  • mpstat: Displays detailed CPU statistics, including cache and memory usage.