Process File

Abstract

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• For Linux, we can view the process info in the form of file under /proc/PID in human-readable text format
• It allows us to view and modify parameters, automate with shell scripts
• We also feed these real-time system information to monitoring tools (like htop) without requiring special APIs

Key files

• cmdline: Contains the command line arguments used to start the process
• environ: Contains the environment variables for the process
• fd: Directory containing symbolic links to files the process has open
• maps: Memory mapping information, useful for debugging memory issues
• status: General process status information (state, memory usage, etc.)
• limits: Resource limits for the process
• io: I/O statistics for the process

These files are useful for

• Performance monitoring and troubleshooting
• Resource usage of critical trading applications
• Debugging latency issues by examining process states

Fast speed

/proc is memory-backed, so info retrieval is going to be very fast.

References

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• The Linux Programming Interface, Chapter 2, Section 19