cpuwalk.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

🎀 NAME 🎀

okay so this manual is for cpuwalk.bt(8), from the System Manager's Manual 💅 It's the bestie that tells you which CPUs are actually running processes. cpuwalk.bt is a bpftrace/eBPF tool that samples the sample which CPUs are executing processes.. 🧚

✨ SYNOPSIS ✨

cpuwalk.bt

💖 DESCRIPTION 💖

okay so this tool samples your CPUs at 99 Hertz 🔥 and then prints a histogram showing which CPUs were active. Why 99 and not a nice round 100? Because 99 Hertz avoids lockstep sampling, which would skew your results. It's giving accuracy 😭

This is the vibe check for your app: it can help you figure out if your workload is evenly spreading across the CPUs, or if there's an imbalance problem 💀

Since this uses BPF, only the root user can use this tool. No cap, you need to be root 👑

🦋 REQUIREMENTS 🦋

You'll need CONFIG_BPF and bpftrace. Those are the non-negotiables, bestie ✨

🌸 EXAMPLES 🌸

Sample the CPUs and get a summary when you hit Ctrl-C 🎀

# cpuwalk.bt

🍓 FIELDS 🍓

  • 1st, 2nd — The CPU shows up in the first field, right after the [. Ignore the second field, it's not the main character here 🙈
  • 3rd — A column with the number of samples for that CPU 🔢
  • 4th — An ASCII histogram that visualizes the count column. Cute bar chart energy 📊

🌈 OVERHEAD 🌈

This should be negligible 🫶 Basically no drama on your system.

💜 SOURCE 💜

This one is from bpftrace, obviously 🧚

https://github.com/bpftrace/bpftrace

Also, go look in the bpftrace distribution for a companion _examples.txt file. It has example usage, output, and commentary for this tool, so it's lowkey the best study guide 📚✨

🦄 OS 🦄

Linux 🐧 only, babe.

🧪 STABILITY 🧪

Unstable - in development. So it's still cooking, don't be shocked if things shift 🙈

👑 AUTHOR 👑

Brendan Gregg 🙌 the legend himself.

🔮 SEE ALSO 🔮

mpstat(1) is your bestie for this one 💅

Sign-off: this page was from USER COMMANDS, dated 2018-09-08, and it's cpuwalk.bt(8) 🎀💖 ily, go sample those CPUs ✨

📦 where this page comes from