acpi_pptt_cpu_is_thread(9)

💅 acpi_pptt_cpu_is_thread(9) — a Kernel API Manual moment

okay so bestie, welcome to the Kernel API Manual entry for acpi_pptt_cpu_is_thread, and no cap, this one is a little cutie. it does exactly one thing and it does it slayfully: it tells you whether a given CPU is actually a thread. that's it. that's the vibe. 🦋

---

✨ NAME ✨

acpi_pptt_cpu_is_thread — Determine if CPU is a thread 💖

literally the whole personality of this function, right there in the name. iykyk.

---

🌸 SYNOPSIS 🌸

int acpi_pptt_cpu_is_thread (unsigned int cpu );

yes bestie, that's the whole signature. int in, int out, one argument, zero drama. 🎀

---

🧚 ARGUMENTS 🧚

• cpu — the Kernel logical CPU number. like, which CPU are we even talking about here? that one. the logical one. not a physical thing, a kernel logical number, okay? important distinction, don't @ me. 💅

---

👑 RETURN 👑

the return value is giving very much "yes / no / excuse me":

• 1 — it's a thread, bestie! 🎉 a thread!
• 0 — not a thread. nope. not even a little. 💀
• -ENOENT — ok so this is the sad one 😭. you get this if the PPTT doesn't exist, OR the CPU cannot be found, OR the table revision isn't new enough. three whole reasons, one error code. we love efficiency (we don't, but go off).

fr fr though, if you see -ENOENT don't panic — it just means one of those three things happened. check your PPTT situation before you assume anything else. 🙈

---

🫶 SEE ALSO 🫶

like, the whole friend group is here, and honestly? iconic lineup. all of these live in the Kernel file ./drivers/acpi/pptt.c 🌈:

• 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)
• 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)

that's a LOT of besties, and every single one of them is doing their own little job. main character energy all around. ⭐

---

and that's the whole page, babe. this one came to us from ./drivers/acpi, dated October 2026 — so like, mark your calendar, she's stamped and official. 💜✨ go forth and check your threads, bestie. 🧚‍♀️