swapin.bt(8)

📦
version 0.27.0 · 3 versions
  • 0.27.0 · alpine 3.24, arch rolling, centos-stream 10, centos-stream 9, debian trixie, fedora 43, fedora 44, nixos 26.05, nixpkgs unstable, opensuse-leap 16.0, ubuntu questing, ubuntu resolute, ubuntu stonking (latest)
  • 0.14.0 · ubuntu jammy
  • 0.20.2 · ubuntu noble
, in alpine 3.24, arch rolling, centos-stream 10, centos-stream 9, debian trixie, fedora 43, fedora 44, nixos 26.05, nixpkgs unstable, opensuse-leap 16.0, ubuntu questing, ubuntu resolute, ubuntu stonking

✨ swapin.bt(8) — System Manager's Manual ✨

💖 NAME

swapin.bt — okay so this one counts swapins per process 🔥. Powered by bpftrace/eBPF, obviously.

🎀 SYNOPSIS

swapin

🦋 DESCRIPTION

okay so this tool counts swapins by process 👀, which shows you which process is getting hit by swapping (if you've got swap devices in use). ngl this can explain a seriously big chunk of app latency, especially if something started swapping because the system is under memory pressure 😭.

It works by tracing the swap_readpage() kernel function using dynamic instrumentation 🧚. Heads up bestie: this tool might need maintenance to keep working if that function changes in later kernels ⚠️.

Since this uses BPF, only the root user can use this tool 🔐.

🌸 REQUIREMENTS

You'll need CONFIG_BPF and bpftrace 💅.

⭐ EXAMPLES

Count swapins by process, showing per-second summaries 📊.

# swapin.bt

🍓 FIELDS

  • 1st — the process name 🫶.
  • 2nd — the process ID 🆔.
  • 3rd — the count of swapins during that interval 🔢.

💜 OVERHEAD

The rate of swapins should be low (bounded by swapin device IOPS), so the overhead of this tool is expected to be negligible 🥰. Literally no drama.

🌈 SOURCE

This tool originated from the book "BPF Performance Tools", published by Addison Wesley (2019) 📚:

http://www.brendangregg.com/bpf-performance-tools-book.html

See the book for more documentation on this tool 🤓.

This version is in the bpftrace repository:

https://github.com/bpftrace/bpftrace

Also look in the bpftrace distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool 🧠.

👑 OS

Linux 🐧.

🙈 STABILITY

Unstable - in development 🚧. Be gentle with it, it's still growing up 🥺.

💅 AUTHOR

Brendan Gregg 👑.

🔥 SEE ALSO

swapon(8) — the swap-enabling partner you'll want to check out 💫.

USER COMMANDS · swapin.bt(8) · bpftrace's swapin tool, dated 2019-07-05 💖 stay iconic, bestie ✨

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