linux-stable.git/Documentation/admin-guide/pm, branch v6.11 Linux kernel stable tree cpufreq: docs: Add missing scaling_available_frequencies description 2024-07-02T18:51:08+00:00 Raphael Gallais-Pou rgallaispou@gmail.com 2024-07-01T17:10:40+00:00 29acea1a043fa98d19d85a9bc614bed4aa0a58af Add a description of the scaling_available_frequencies attribute in sysfs to the documentation. Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Link: https://patch.msgid.link/20240701171040.369030-1-rgallaispou@gmail.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Add a description of the scaling_available_frequencies attribute in
sysfs to the documentation.

Signed-off-by: Raphael Gallais-Pou <rgallaispou@gmail.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/20240701171040.369030-1-rgallaispou@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Documentation: cpufreq: amd-pstate: update doc for Per CPU boost control method 2024-06-26T20:48:21+00:00 Perry Yuan perry.yuan@amd.com 2024-06-26T04:27:33+00:00 6d588891a90c5a946aaac11a93d06edd89ed9054 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 <gautham.shenoy@amd.com> Signed-off-by: Perry Yuan <perry.yuan@amd.com> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com> Link: https://lore.kernel.org/r/20240626042733.3747-5-mario.limonciello@amd.com Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> 
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 <gautham.shenoy@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20240626042733.3747-5-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Documentation: PM: amd-pstate: add guided mode to the Operation mode 2024-06-21T02:52:05+00:00 Perry Yuan perry.yuan@amd.com 2024-06-19T15:40:16+00:00 1d53f30b3aa6120ca91789254cb2dfff9ff8c533 the guided mode is also supported, so the operation mode should include that mode as well. Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Perry Yuan <perry.yuan@amd.com> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Link: https://lore.kernel.org/r/a61d825ef71f6aacc8f1624fe9fb982b8446b5a7.1718811234.git.perry.yuan@amd.com Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> 
the guided mode is also supported, so the operation mode should include
that mode as well.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/a61d825ef71f6aacc8f1624fe9fb982b8446b5a7.1718811234.git.perry.yuan@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Documentation: PM: amd-pstate: Fix section title underline 2024-02-12T13:40:32+00:00 Meng Li li.meng@amd.com 2024-02-05T06:03:05+00:00 4c7dbd85218d6e2ed0495bbaf40c1b1c6bac506b Title under line too short Signed-off-by: Meng Li <li.meng@amd.com> [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Title under line too short

Signed-off-by: Meng Li <li.meng@amd.com>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Documentation: amd-pstate: introduce amd-pstate preferred core 2024-01-31T13:54:50+00:00 Meng Li li.meng@amd.com 2024-01-19T09:05:01+00:00 3a004e1fee4ba3d37976c1a9707869acc8d60b55 Introduce amd-pstate preferred core. check preferred core state set by the kernel parameter: $ cat /sys/devices/system/cpu/amd-pstate/prefcore Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Reviewed-by: Wyes Karny <wyes.karny@amd.com> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Reviewed-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Perry Yuan <perry.yuan@amd.com> Signed-off-by: Meng Li <li.meng@amd.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Introduce amd-pstate preferred core.

check preferred core state set by the kernel parameter:
$ cat /sys/devices/system/cpu/amd-pstate/prefcore

Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reviewed-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Meng Li <li.meng@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Documentation: admin-guide: PM: Fix two typos 2024-01-10T14:10:44+00:00 Erwan Velu erwanaliasr1@gmail.com 2024-01-09T17:57:53+00:00 03c305861c70d6db898dd2379b882e7772a5c5d0 Fix two typos in the admin-guide: - a missing e in "reference_perf" in cppc_sysfs.rst. - the amd_pstate sysfs path uses a dash instead of an underscore. Signed-off-by: Erwan Velu <e.velu@criteo.com> [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Fix two typos in the admin-guide:

 - a missing e in "reference_perf" in cppc_sysfs.rst.
 - the amd_pstate sysfs path uses a dash instead of an underscore.

Signed-off-by: Erwan Velu <e.velu@criteo.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
intel_idle: Add ibrs_off module parameter to force-disable IBRS 2023-10-07T09:33:28+00:00 Waiman Long longman@redhat.com 2023-07-27T18:46:00+00:00 aa1567a7e6440b8c3af4b0d8a8219d8fc5028c5f Commit bf5835bcdb96 ("intel_idle: Disable IBRS during long idle") disables IBRS when the cstate is 6 or lower. However, there are some use cases where a customer may want to use max_cstate=1 to lower latency. Such use cases will suffer from the performance degradation caused by the enabling of IBRS in the sibling idle thread. Add a "ibrs_off" module parameter to force disable IBRS and the CPUIDLE_FLAG_IRQ_ENABLE flag if set. In the case of a Skylake server with max_cstate=1, this new ibrs_off option will likely increase the IRQ response latency as IRQ will now be disabled. When running SPECjbb2015 with cstates set to C1 on a Skylake system. First test when the kernel is booted with: "intel_idle.ibrs_off": max-jOPS = 117828, critical-jOPS = 66047 Then retest when the kernel is booted without the "intel_idle.ibrs_off" added: max-jOPS = 116408, critical-jOPS = 58958 That means booting with "intel_idle.ibrs_off" improves performance by: max-jOPS: +1.2%, which could be considered noise range. critical-jOPS: +12%, which is definitely a solid improvement. The admin-guide/pm/intel_idle.rst file is updated to add a description about the new "ibrs_off" module parameter. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20230727184600.26768-5-longman@redhat.com 
Commit bf5835bcdb96 ("intel_idle: Disable IBRS during long idle")
disables IBRS when the cstate is 6 or lower. However, there are
some use cases where a customer may want to use max_cstate=1 to
lower latency. Such use cases will suffer from the performance
degradation caused by the enabling of IBRS in the sibling idle thread.
Add a "ibrs_off" module parameter to force disable IBRS and the
CPUIDLE_FLAG_IRQ_ENABLE flag if set.

In the case of a Skylake server with max_cstate=1, this new ibrs_off
option will likely increase the IRQ response latency as IRQ will now
be disabled.

When running SPECjbb2015 with cstates set to C1 on a Skylake system.

First test when the kernel is booted with: "intel_idle.ibrs_off":

  max-jOPS = 117828, critical-jOPS = 66047

Then retest when the kernel is booted without the "intel_idle.ibrs_off"
added:

  max-jOPS = 116408, critical-jOPS = 58958

That means booting with "intel_idle.ibrs_off" improves performance by:

  max-jOPS:      +1.2%, which could be considered noise range.
  critical-jOPS: +12%,  which is definitely a solid improvement.

The admin-guide/pm/intel_idle.rst file is updated to add a description
about the new "ibrs_off" module parameter.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20230727184600.26768-5-longman@redhat.com
platform/x86/intel-uncore-freq: Support for cluster level controls 2023-05-09T09:54:42+00:00 Srinivas Pandruvada srinivas.pandruvada@linux.intel.com 2023-04-18T17:13:39+00:00 9b8dea80e3cb22e1fed4f974841116e10a3dbb35 An SoC can contain multiple power domains with individual or collection of mesh partitions. This partition is called fabric cluster. Certain type of meshes will need to run at the same frequency, they will be placed in the same fabric cluster. Benefit of fabric cluster is that it offers a scalable mechanism to deal with partitioned fabrics in a SoC. The current sysfs interface supports control at package and die level. This interface is not enough to support more granular control at fabric cluster level. SoCs with the support of TPMI (Topology Aware Register and PM Capsule Interface), can have multiple power domains. Each power domain can contain one or more fabric clusters. To support such granular controls, enhance uncore common to optionally create new directories to provide controls at fabric cluster level. It is also important to have flexibility to change granularity for future version of SoCs. If the directory name contains scope like: "package_*_die_*_power_domain_*_cluster_*", then this is not expandable. The cpufreq policies also have different scopes. There the scope of the policy (affected_cpus) specified by attributes inside each policy. So, follow the same model for uncore frequency scaling sysfs as: "sys/devices/system/cpu/cpufreq/policy*" Allow client drivers to optionally support granular control for each fabric cluster. Here, the directory name will be "uncore" suffixed with an unique instance number. For example: uncore00, uncore01 etc. Attributes in the directory identify package id, power domain and fabric cluster id. This interface is expandable even if some new level of granularity is introduced. A new sysfs attribute can identify new level. For compatibility with the existing sysfs and provide easy way to set limits for each fabric cluster in the package/die, the existing control at package/die levels are still provided. For majority of users, this is an easy approach. For example: On a single package/die system, with three power domains and one fabric cluster per power domain: $tree -L 2 /sys/devices/system/cpu/intel_uncore_frequency/ /sys/devices/system/cpu/intel_uncore_frequency/ ├── package_00_die_00 │   ├── current_freq_khz │   ├── initial_max_freq_khz │   ├── initial_min_freq_khz │   ├── max_freq_khz │   └── min_freq_khz ├── uncore00 │   ├── current_freq_khz │   ├── domain_id │   ├── fabric_cluster_id │   ├── initial_max_freq_khz │   ├── initial_min_freq_khz │   ├── max_freq_khz │   ├── min_freq_khz │   └── package_id ├── uncore01 │   ├── current_freq_khz │   ├── domain_id │   ├── fabric_cluster_id │   ├── initial_max_freq_khz │   ├── initial_min_freq_khz │   ├── max_freq_khz │   ├── min_freq_khz │   └── package_id └── uncore02 ├── current_freq_khz ├── domain_id ├── fabric_cluster_id ├── initial_max_freq_khz ├── initial_min_freq_khz ├── max_freq_khz ├── min_freq_khz └── package_id The attribute for cluster id is "fabric_cluster_id" instead of just "cluster_id" is to avoid confusion with usage of term clusters in other part of the Linux kernel. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Zhang Rui <rui.zhang@intel.com> Tested-by: Wendy Wang <wendy.wang@intel.com> Link: https://lore.kernel.org/r/20230418171340.681662-3-srinivas.pandruvada@linux.intel.com Signed-off-by: Hans de Goede <hdegoede@redhat.com> 
An SoC can contain multiple power domains with individual or collection
of mesh partitions. This partition is called fabric cluster.

Certain type of meshes will need to run at the same frequency, they will
be placed in the same fabric cluster. Benefit of fabric cluster is that
it offers a scalable mechanism to deal with partitioned fabrics in a SoC.

The current sysfs interface supports control at package and die level.
This interface is not enough to support more granular control at
fabric cluster level.

SoCs with the support of TPMI (Topology Aware Register and PM Capsule
Interface), can have multiple power domains. Each power domain can
contain one or more fabric clusters.

To support such granular controls, enhance uncore common to optionally
create new directories to provide controls at fabric cluster level. It
is also important to have flexibility to change granularity for future
version of SoCs. If the directory name contains scope like:
"package_*_die_*_power_domain_*_cluster_*", then this is not expandable.

The cpufreq policies also have different scopes. There the scope of the
policy (affected_cpus) specified by attributes inside each policy.
So, follow the same model for uncore frequency scaling sysfs as:
"sys/devices/system/cpu/cpufreq/policy*"

Allow client drivers to optionally support granular control for each
fabric cluster. Here, the directory name will be "uncore" suffixed with
an unique instance number. For example: uncore00, uncore01 etc.
Attributes in the directory identify package id, power domain and
fabric cluster id. This interface is expandable even if some new level
of granularity is introduced. A new sysfs attribute can identify new
level.

For compatibility with the existing sysfs and provide easy way to set
limits for each fabric cluster in the package/die, the existing control
at package/die levels are still provided. For majority of users, this is
an easy approach.

For example: On a single package/die system, with three power domains
and one fabric cluster per power domain:

$tree -L 2 /sys/devices/system/cpu/intel_uncore_frequency/
/sys/devices/system/cpu/intel_uncore_frequency/
├── package_00_die_00
│   ├── current_freq_khz
│   ├── initial_max_freq_khz
│   ├── initial_min_freq_khz
│   ├── max_freq_khz
│   └── min_freq_khz
├── uncore00
│   ├── current_freq_khz
│   ├── domain_id
│   ├── fabric_cluster_id
│   ├── initial_max_freq_khz
│   ├── initial_min_freq_khz
│   ├── max_freq_khz
│   ├── min_freq_khz
│   └── package_id
├── uncore01
│   ├── current_freq_khz
│   ├── domain_id
│   ├── fabric_cluster_id
│   ├── initial_max_freq_khz
│   ├── initial_min_freq_khz
│   ├── max_freq_khz
│   ├── min_freq_khz
│   └── package_id
└── uncore02
    ├── current_freq_khz
    ├── domain_id
    ├── fabric_cluster_id
    ├── initial_max_freq_khz
    ├── initial_min_freq_khz
    ├── max_freq_khz
    ├── min_freq_khz
    └── package_id

The attribute for cluster id is "fabric_cluster_id" instead of just
"cluster_id" is to avoid confusion with usage of term clusters in
other part of the Linux kernel.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: Wendy Wang <wendy.wang@intel.com>
Link: https://lore.kernel.org/r/20230418171340.681662-3-srinivas.pandruvada@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Documentation: cpufreq: amd-pstate: Update amd_pstate status sysfs for guided 2023-03-17T18:06:23+00:00 Wyes Karny wyes.karny@amd.com 2023-03-07T11:27:40+00:00 7a9dec665f6875f61fe0c2e71b25842daade5110 Update amd_pstate status sysfs for guided mode. Acked-by: Huang Rui <ray.huang@amd.com> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Wyes Karny <wyes.karny@amd.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Update amd_pstate status sysfs for guided mode.

Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge tag 'docs-6.3' of git://git.lwn.net/linux 2023-02-22T20:00:20+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-02-22T20:00:20+00:00 70756b49be4ea8bf36a664322df6e7e89895fa60 Pull documentation updates from Jonathan Corbet: "It has been a moderately calm cycle for documentation; the significant changes include: - Some significant additions to the memory-management documentation - Some improvements to navigation in the HTML-rendered docs - More Spanish and Chinese translations ... and the usual set of typo fixes and such" * tag 'docs-6.3' of git://git.lwn.net/linux: (68 commits) Documentation/watchdog/hpwdt: Fix Format Documentation/watchdog/hpwdt: Fix Reference Documentation: core-api: padata: correct spelling docs/mm: Physical Memory: correct spelling in reference to CONFIG_PAGE_EXTENSION docs: Use HTML comments for the kernel-toc SPDX line docs: Add more information to the HTML sidebar Documentation: KVM: Update AMD memory encryption link printk: Document that CONFIG_BOOT_PRINTK_DELAY required for boot_delay= Documentation: userspace-api: correct spelling Documentation: sparc: correct spelling Documentation: driver-api: correct spelling Documentation: admin-guide: correct spelling docs: add workload-tracing document to admin-guide docs/admin-guide/mm: remove useless markup docs/mm: remove useless markup docs/mm: Physical Memory: remove useless markup docs/sp_SP: Add process magic-number translation docs: ftrace: always use canonical ftrace path Doc/damon: fix the data path error dma-buf: Add "dma-buf" to title of documentation ... 
Pull documentation updates from Jonathan Corbet:
 "It has been a moderately calm cycle for documentation; the significant
  changes include:

   - Some significant additions to the memory-management documentation

   - Some improvements to navigation in the HTML-rendered docs

   - More Spanish and Chinese translations

  ... and the usual set of typo fixes and such"

* tag 'docs-6.3' of git://git.lwn.net/linux: (68 commits)
  Documentation/watchdog/hpwdt: Fix Format
  Documentation/watchdog/hpwdt: Fix Reference
  Documentation: core-api: padata: correct spelling
  docs/mm: Physical Memory: correct spelling in reference to CONFIG_PAGE_EXTENSION
  docs: Use HTML comments for the kernel-toc SPDX line
  docs: Add more information to the HTML sidebar
  Documentation: KVM: Update AMD memory encryption link
  printk: Document that CONFIG_BOOT_PRINTK_DELAY required for boot_delay=
  Documentation: userspace-api: correct spelling
  Documentation: sparc: correct spelling
  Documentation: driver-api: correct spelling
  Documentation: admin-guide: correct spelling
  docs: add workload-tracing document to admin-guide
  docs/admin-guide/mm: remove useless markup
  docs/mm: remove useless markup
  docs/mm: Physical Memory: remove useless markup
  docs/sp_SP: Add process magic-number translation
  docs: ftrace: always use canonical ftrace path
  Doc/damon: fix the data path error
  dma-buf: Add "dma-buf" to title of documentation
  ...