evlist__warn...quested_cpus(9)

💅 evlist__warn...quested_cpus(9) 💅

okay so bestie, we're in the Kernel API Manual today — yes, that one — and this lil function has a name that got snipped in half for the header (evlist__warn...quested_cpus), but the real, full, un-abbreviated queen is evlist__warn_user_requested_cpus. She's the whole main character of this page. let's get into it 🫶

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✨ NAME ✨

evlist__warn_user_requested_cpus — the vibe-checker that looks at every evsel against the requested CPUs and warns you if your CPU list is, like, totally inapplicable for that event's PMU's CPUs. 🎀

and here's the lore, fr fr: not core PMUs list a CPU in sysfs, but that can get overwritten by a user requested CPU, and so literally any online CPU is applicable. Core PMUs, though? they handle events on the CPUs in their own list — and otherwise the event isn't supported, periodt. 😭

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🌈 SYNOPSIS 🌈

void evlist__warn_user_requested_cpus (struct evlist *evlist , const char *cpu_list );

that's it. that's the whole signature. no cap. 💖

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🦋 ARGUMENTS 🦋

• evlist — the list of events being checked. like, the whole squad that's getting inspected, bestie. 👑
• cpu_list — the user provided list of CPUs. yeah, the one you handed over. it's getting compared. 👀

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🌸 SEE ALSO 🌸

• Kernel file ./tools/perf/util/evlist.c
• evlist__set_id_pos(9)
• evlist__mmap_ex(9)
• struct event_enable_time(9)
• struct event_enable_timer(9)

go read those too, iykyk. ✨

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ngl bestie, the takeaway is: this function doesn't fix your CPU list, it just warns you when your CPU list doesn't vibe with the event's PMU's CPUs. lowkey helpful, highkey a snitch. 🔥

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and that's the page! 🧚 this one's a ./tools/perf/util production, dated October 2026 — go off, October 2026, you ate. 💜