[PATCH] hwmon: (coretemp) Document sysfs numbering and label meaning

From: Asaf Nuri Bertizlioğlu

Date: Thu Oct 15 2026 - 13:26:12 EST


The documentation says that all sysfs entries are named with their
core_id, and that the "Core X" label contains the processor number.
Neither is accurate. create_core_attrs() numbers the per-core
attributes core_id + 2 and always uses temp1 for the package sensor,
and show_label() prints topology_core_id(), not the logical CPU
number.

The difference is easy to see on hybrid CPUs. On an i7-14700F, the
"Core 4" label is on temp6 and belongs to CPUs 2 and 3, and the
E-cores report core IDs 32 to 43.

Describe the actual numbering.

The mismatch was found by an LLM comparing the documentation with the
code, and verified on the i7-14700F above.

Assisted-by: LLM
Signed-off-by: Asaf Nuri Bertizlioğlu <ycistak@xxxxxxxxx>
---

Notes:
The LLM (Claude) also drafted the documentation change and this
changelog. Values checked on my machine: temp6_label is "Core 4",
cpu2 and cpu3 have core_id 4, temp1_label is "Package id 0".

Documentation/hwmon/coretemp.rst | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/Documentation/hwmon/coretemp.rst b/Documentation/hwmon/coretemp.rst
index 34930168338..95b0a578c4d 100644
--- a/Documentation/hwmon/coretemp.rst
+++ b/Documentation/hwmon/coretemp.rst
@@ -46,7 +46,8 @@ mechanism will perform actions to forcibly cool down the processor. Alarm
may be raised, if the temperature grows enough (more than TjMax) to trigger
the Out-Of-Spec bit. The following table summarizes the exported sysfs files:

-All sysfs entries are named with their core_id (represented here by 'X').
+Per-core sysfs entries are numbered core_id + 2 (represented here by 'X').
+The package entries, if available, are always temp1_*.

================= ========================================================
tempX_input Core temperature (in millidegrees Celsius).
@@ -55,9 +56,12 @@ tempX_max Maximum recommended operating temperature (Tcontrol).
tempX_crit Maximum junction temperature (in millidegrees Celsius).
tempX_crit_alarm Set when Out-of-spec bit is set, never clears.
Correct CPU operation is no longer guaranteed.
-tempX_label Contains string "Core X", where X is processor
- number. For Package temp, this will be "Package id Y",
- where Y is the package number.
+tempX_label Contains string "Core N", where N is the core_id
+ (X - 2), as shown in
+ /sys/devices/system/cpu/cpu*/topology/core_id. This
+ is not the logical CPU number, and core_id values
+ may be sparse. For Package temp, this will be
+ "Package id Y", where Y is the package number.
================= ========================================================

On modern CPUs (Nehalem and newer), TjMax is read from the
--
2.56.0