3 months ago
- Memory usage reporting is complex due to OS caching mechanisms like disk caching in RAM for performance, which can be freed when needed.
- Virtual Memory (VM) systems manage RAM pages in queues (active, inactive, laundry, wired, free), making it hard to define 'used' vs. 'free' memory accurately.
- Tools like fastfetch, btop, and htop use different heuristics to report memory usage, leading to discrepancies in displayed values.
- btop had bugs on FreeBSD, including integer overflow with 32-bit variables and incorrect cache reporting due to using a legacy sysctl parameter.
- Fixes were implemented for btop and htop to correctly account for ZFS ARC cache and filesystem buffers, improving memory monitoring accuracy.
- The author contributed patches to open-source projects, highlighting the importance of understanding OS internals for accurate system monitoring.