em_dev_update_perf_domain(9)

✨ NAME ✨

okay so bestie, this is em_dev_update_perf_domain(9) from the Kernel API Manual, and it's literally the function that updates the runtime EM table for a device 💅 no cap.

✨ SYNOPSIS ✨

int em_dev_update_perf_domain (struct device *dev , struct em_perf_table
*new_table );

✨ ARGUMENTS ✨

• dev — the device whose EM is getting updated 🛠️ like, this is the main character of the operation.
• new_table — the new EM table that's going to be used from now on, periodt ✨

✨ DESCRIPTION ✨

so the vibe is: this function updates the EM runtime modifiable table for the dev using the table you just handed it 🫶.

it uses a mutex to serialize writers, so it must NOT be called from a non-sleeping context — that's a hard no, bestie, do not try it 😭.

it returns 0 on success or an error code on failure. slay.

✨ SEE ALSO ✨

check out the kernel file ./kernel/power/energy_model.c and these iconic functions:

• em_table_free(9)
• em_table_alloc(9)
• em_dev_compute_costs(9)
• em_pd_get(9)
• em_cpu_get(9)
• em_dev_register_perf_domain(9)
• em_dev_register_pd_no_update(9)
• em_dev_unregister_perf_domain(9)
• em_adjust_cpu_capacity(9)
• em_dev_update_chip_binning(9)
• em_update_performance_limits(9)

this page is brought to you by ./kernel/power, dated October 2026 — mwah 💋 go update those perf domains responsibly, bestie 🎀