perf_cpu_ma..._online_cpus(9)

okay bestie, you opened perf_cpu_ma..._online_cpus(9) in the Kernel API Manual and we are gonna get you comfy with it 🫶✨

🎀 NAME 🎀

perf_cpu_map__new_online_cpus — it gives you a map read from /sys/devices/system/cpu/online if that file is available 💖

and if reading wasn’t possible? no stress, it creates a map using the online processors and assumes the first n processors are all online. that’s the vibe check. 🦋

✨ SYNOPSIS ✨

LIBPERF_API struct perf_cpu_map * perf_cpu_map__new_online_cpus (void );

🌸 ARGUMENTS 🌸

• void — no arguments. literally none. not even a sneaky little parameter, bestie 💀

👑 SEE ALSO 👑

Kernel file ./tools/lib/perf/include/perf/cpumap.h, plus the whole CPU-map friend group:

• struct perf_cpu(9)
• perf_cpu_map__new_any_cpu(9)
• perf_cpu_map__new(9)
• perf_cpu_map__cpu(9)
• perf_cpu_map__nr(9)
• perf_cpu_map__has_any_cpu_or_is_empty(9)
• perf_cpu_map__is_any_cpu_or_is_empty(9)
• perf_cpu_map__is_empty(9)
• perf_cpu_map__min(9)
• perf_cpu_map__max(9)

source/version: ./tools/lib/perf/include/perf · date: October 2026 — bye bestie, go slay those CPU maps 💅🌈