From 6d588891a90c5a946aaac11a93d06edd89ed9054 Mon Sep 17 00:00:00 2001 From: Perry Yuan Date: Tue, 25 Jun 2024 23:27:33 -0500 Subject: [PATCH] Documentation: cpufreq: amd-pstate: update doc for Per CPU boost control method Updates the documentation in `amd-pstate.rst` to include information about the per CPU boost control feature. Users can now enable or disable the Core Performance Boost (CPB) feature on individual CPUs using the `boost` sysfs attribute. Reviewed-by: Gautham R. Shenoy Signed-off-by: Perry Yuan Co-developed-by: Mario Limonciello Link: https://lore.kernel.org/r/20240626042733.3747-5-mario.limonciello@amd.com Signed-off-by: Mario Limonciello --- Documentation/admin-guide/pm/amd-pstate.rst | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst index f5ee81419a935..d0324d44f5482 100644 --- a/Documentation/admin-guide/pm/amd-pstate.rst +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -281,6 +281,22 @@ integer values defined between 0 to 255 when EPP feature is enabled by platform firmware, if EPP feature is disabled, driver will ignore the written value This attribute is read-write. +``boost`` +The `boost` sysfs attribute provides control over the CPU core +performance boost, allowing users to manage the maximum frequency limitation +of the CPU. This attribute can be used to enable or disable the boost feature +on individual CPUs. + +When the boost feature is enabled, the CPU can dynamically increase its frequency +beyond the base frequency, providing enhanced performance for demanding workloads. +On the other hand, disabling the boost feature restricts the CPU to operate at the +base frequency, which may be desirable in certain scenarios to prioritize power +efficiency or manage temperature. + +To manipulate the `boost` attribute, users can write a value of `0` to disable the +boost or `1` to enable it, for the respective CPU using the sysfs path +`/sys/devices/system/cpu/cpuX/cpufreq/boost`, where `X` represents the CPU number. + Other performance and frequency values can be read back from ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.