find_acpi_cpu_topology(9)

💅 find_acpi_cpu_topology(9) — from the Kernel API Manual, bestie 🎀

okay so picture this: it's a (9) section page, kernel API manual energy, and the whole thing is about handing you back one (1) unique little number that tells you where a CPU sits in the whole thread/core/cluster/mc_grouping/socket/etc. food chain. she's an icon, she's a lookup function, let's get into it ✨

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🌸 SYNOPSIS 🌸

int find_acpi_cpu_topology (unsigned int cpu , int level );

literally the whole signature, no notes 💅

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🦋 ARGUMENTS 🦋

• cpu — the kernel logical CPU number, i.e. which CPU you're asking about, bestie 🫶
• level — the topological level you want a unique ID for — the whole point of the call, no cap 👑

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✨ DESCRIPTION ✨

so what she does is: determine a topology unique ID for each thread / core / cluster / mc_grouping / socket / etc. 🧚 that ID is then your little grouping key — peers that match IDs get to be grouped together, fr fr. matching ids = same squad 💖

and here's the important bit about how the search goes: it terminates when either the requested level is found or we hit a root node. that's it, that's the stop condition 🌈

now — levels beyond the termination point? they'll return the same unique ID. so don't come for her expecting fresh numbers past the finish line, okay 😭

the unique id for level 0 is the acpi processor id. iconic. everything above level 0 uses a generated value to uniquely identify a topological feature — so level 0 gets the real deal, the rest get handcrafted artisanal generated IDs 🎀

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💀 RETURN 💀

• -ENOENT — if the PPTT doesn't exist, or the CPU cannot be found 🙈 (yes, both of those, same error, that's just how she is)
• otherwise — a value which represents a unique topological feature ⭐

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🔥 SEE ALSO 🔥

kernel file ./drivers/acpi/pptt.c — and the whole bestie squad, all of them, in order, because we don't do partial lists here 👑

• acpi_pptt_walk_cache(9)
• acpi_count_levels(9)
• acpi_pptt_leaf_node(9)
• acpi_find_processor_node(9)
• update_cache_properties(9)
• topology_get_acpi_cpu_tag(9)
• check_acpi_cpu_flag(9)
• acpi_get_cache_info(9)
• cache_setup_acpi(9)
• acpi_pptt_cpu_is_thread(9)
• find_acpi_cpu_topology_package(9)
• find_acpi_cpu_topology_cluster(9)
• find_acpi_cpu_topology_hetero_id(9)
• acpi_pptt_get_child_cpus(9)
• acpi_pptt_get_cpus_from_container(9)
• find_acpi_cache_level_from_id(9)
• acpi_pptt_get_cpumask_from_cache_id(9)

ngl that's a lot of siblings, but they all ate and left no crumbs 🍓

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🌟 a lil sign-off 🌟

this page lives in ./drivers/acpi (that's the source/version vibe, bestie), and it was dated October 2026 — so yes, this manpage is from the future and she's still serving 💜

kisses, go group your peers correctly, mwah 🫶💖