acpi_get_cache_info(9)

💅 acpi_get_cache_info — Kernel API Manual, section 9, bestie

okay so picture this: it's a (9) manpage, it lives in the Kernel API Manual, and its whole personality is "tell me about the caches on this PE." iconic behavior honestly.

---

✨ NAME ✨

acpi_get_cache_info — determine the number of cache levels and split cache levels (data/instruction) and for a PE. 🎀

🦋 SYNOPSIS 🦋

int acpi_get_cache_info (unsigned int cpu , unsigned int *levels ,
       unsigned int *split_levels );

🌸 ARGUMENTS 🌸

• cpu — the kernel logical CPU number. like, which CPU are we talking about, bestie? 👀
• levels — number of levels if success. ✨
• split_levels — number of levels being split (i.e. data/instruction) if success. and get this, it can by NULL — yes, that's the manpage's wording, no cap, we do not touch it 🙈

💖 DESCRIPTION 💖

Given a logical CPU number, this returns the number of levels of cache represented in the PPTT. that's the whole vibe. 🧚

but listen — errors caused by lack of a PPTT table, or otherwise, return 0, indicating we didn't find any cache levels. so a 0 here is giving "nothing to see here" energy, not "slay." 💀

🔥 RETURN 🔥

• -ENOENT if no PPTT table, can't get CPU's ACPI Process UID or no PPTT processor struct found. 😭
• 0 on success. 👑

fr fr: -ENOENT = couldn't find the thing. 0 = we're so back.

👑 SEE ALSO 👑

kernel file ./drivers/acpi/pptt.c, plus the whole friend group:

• 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)
• cache_setup_acpi(9)
• acpi_pptt_cpu_is_thread(9)
• find_acpi_cpu_topology(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)

---

and that's the page, bestie 🫶 sourced from ./drivers/acpi, dated October 2026, acpi_get_cache_info(9) — periodt. 💅⭐🌈