JIRA: https://issues.redhat.com/browse/RHEL-8620
Upstream Status: tip commit aa1567a7e6440b8c3af4b0d8a8219d8fc5028c5f
commit aa1567a7e6440b8c3af4b0d8a8219d8fc5028c5f
Author: Waiman Long <longman@redhat.com>
Date: Thu, 27 Jul 2023 14:46:00 -0400
intel_idle: Add ibrs_off module parameter to force-disable IBRS
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
Signed-off-by: Waiman Long <longman@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2177013
commit 9b8dea80e3cb22e1fed4f974841116e10a3dbb35
Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date: Tue Apr 18 10:13:39 2023 -0700
platform/x86/intel-uncore-freq: Support for cluster level controls
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>
Signed-off-by: David Arcari <darcari@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2150425
commit 8a2cbf72a43ade1ed00760f65914e322599fe662
Author: Perry Yuan <Perry.Yuan@amd.com>
Date: Thu Nov 17 15:35:40 2022 +0800
Documentation: amd-pstate: add driver working mode introduction
Introduce the `amd_pstate` driver new working mode with
`amd_pstate=passive` added to kernel command line.
If there is no passive mode enabled by user, amd_pstate driver will be
disabled by default for now.
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: David Arcari <darcari@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2150425
commit 7fe3629729ce5466f865b75c506d7cb6223838ba
Author: Meng Li <li.meng@amd.com>
Date: Wed Aug 17 11:46:30 2022 +0800
Documentation: amd-pstate: Add unit test introduction
Introduce the AMD P-State unit test module design and implementation.
It also talks about kselftest and how to use.
Signed-off-by: Meng Li <li.meng@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: David Arcari <darcari@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2150425
commit 7000ef38052b219583f17a10ef2e7ca99b5e585e
Author: Jan Engelhardt <jengelh@inai.de>
Date: Wed Mar 23 11:26:02 2022 +0100
Documentation: amd-pstate: grammar and sentence structure updates
Signed-off-by: Jan Engelhardt <jengelh@inai.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: David Arcari <darcari@redhat.com>
Bugzilla: https://bugzilla.redhat.com/2150068
commit 8bcedb4ce04750e1ccc9a6b6433387f6a9166a56
Author: Wyes Karny <wyes.karny@amd.com>
Date: Mon Jun 6 23:33:34 2022 +0530
x86: Handle idle=nomwait cmdline properly for x86_idle
When kernel is booted with idle=nomwait do not use MWAIT as the
default idle state.
If the user boots the kernel with idle=nomwait, it is a clear
direction to not use mwait as the default idle state.
However, the current code does not take this into consideration
while selecting the default idle state on x86.
Fix it by checking for the idle=nomwait boot option in
prefer_mwait_c1_over_halt().
Also update the documentation around idle=nomwait appropriately.
[ dhansen: tweak commit message ]
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lkml.kernel.org/r/fdc2dc2d0a1bc21c2f53d989ea2d2ee3ccbc0dbe.1654538381.git-series.wyes.karny@amd.com
Signed-off-by: David Arcari <darcari@redhat.com>
- Make intel_pstate support hybrid processors using abstract
performance units in the HWP interface (Rafael Wysocki).
- Add Icelake servers and Cometlake support in no-HWP mode to
intel_pstate (Giovanni Gherdovich).
- Make cpufreq_online() error path be consistent with the CPU
device removal path in cpufreq (Rafael Wysocki).
- Clean up 3 cpufreq drivers and the statistics code (Hailong Liu,
Randy Dunlap, Shaokun Zhang).
- Make intel_idle use special idle state parameters for C6 when
package C-states are disabled (Chen Yu).
- Rework the TEO (timer events oriented) cpuidle governor to address
some theoretical shortcomings in it (Rafael Wysocki).
- Drop unneeded semicolon from the TEO governor (Wan Jiabing).
- Modify the runtime PM framework to accept unassigned suspend
and resume callback pointers (Ulf Hansson).
- Improve pm_runtime_get_sync() documentation (Krzysztof Kozlowski).
- Improve device performance states support in the generic power
domains (genpd) framework (Ulf Hansson).
- Fix some documentation issues in genpd (Yang Yingliang).
- Make the operating performance points (OPP) framework use the
required-opps DT property in use cases that are not related to
genpd (Hsin-Yi Wang).
- Make lazy_link_required_opp_table() use list_del_init instead of
list_del/INIT_LIST_HEAD (Yang Yingliang).
- Simplify wake IRQs handling in the core system-wide sleep support
code and clean up some coding style inconsistencies in it (Tian
Tao, Zhen Lei).
- Add cooling support to the tegra30 devfreq driver and improve its
DT bindings (Dmitry Osipenko).
- Fix some assorted issues in the devfreq core and drivers (Chanwoo
Choi, Dong Aisheng, YueHaibing).
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Merge tag 'pm-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These add hybrid processors support to the intel_pstate driver and
make it work with more processor models when HWP is disabled, make the
intel_idle driver use special C6 idle state paremeters when package
C-states are disabled, add cooling support to the tegra30 devfreq
driver, rework the TEO (timer events oriented) cpuidle governor,
extend the OPP (operating performance points) framework to use the
required-opps DT property in more cases, fix some issues and clean up
a number of assorted pieces of code.
Specifics:
- Make intel_pstate support hybrid processors using abstract
performance units in the HWP interface (Rafael Wysocki).
- Add Icelake servers and Cometlake support in no-HWP mode to
intel_pstate (Giovanni Gherdovich).
- Make cpufreq_online() error path be consistent with the CPU device
removal path in cpufreq (Rafael Wysocki).
- Clean up 3 cpufreq drivers and the statistics code (Hailong Liu,
Randy Dunlap, Shaokun Zhang).
- Make intel_idle use special idle state parameters for C6 when
package C-states are disabled (Chen Yu).
- Rework the TEO (timer events oriented) cpuidle governor to address
some theoretical shortcomings in it (Rafael Wysocki).
- Drop unneeded semicolon from the TEO governor (Wan Jiabing).
- Modify the runtime PM framework to accept unassigned suspend and
resume callback pointers (Ulf Hansson).
- Improve pm_runtime_get_sync() documentation (Krzysztof Kozlowski).
- Improve device performance states support in the generic power
domains (genpd) framework (Ulf Hansson).
- Fix some documentation issues in genpd (Yang Yingliang).
- Make the operating performance points (OPP) framework use the
required-opps DT property in use cases that are not related to
genpd (Hsin-Yi Wang).
- Make lazy_link_required_opp_table() use list_del_init instead of
list_del/INIT_LIST_HEAD (Yang Yingliang).
- Simplify wake IRQs handling in the core system-wide sleep support
code and clean up some coding style inconsistencies in it (Tian
Tao, Zhen Lei).
- Add cooling support to the tegra30 devfreq driver and improve its
DT bindings (Dmitry Osipenko).
- Fix some assorted issues in the devfreq core and drivers (Chanwoo
Choi, Dong Aisheng, YueHaibing)"
* tag 'pm-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (39 commits)
PM / devfreq: passive: Fix get_target_freq when not using required-opp
cpufreq: Make cpufreq_online() call driver->offline() on errors
opp: Allow required-opps to be used for non genpd use cases
cpuidle: teo: remove unneeded semicolon in teo_select()
dt-bindings: devfreq: tegra30-actmon: Add cooling-cells
dt-bindings: devfreq: tegra30-actmon: Convert to schema
PM / devfreq: userspace: Use DEVICE_ATTR_RW macro
PM: runtime: Clarify documentation when callbacks are unassigned
PM: runtime: Allow unassigned ->runtime_suspend|resume callbacks
PM: runtime: Improve path in rpm_idle() when no callback
PM: hibernate: remove leading spaces before tabs
PM: sleep: remove trailing spaces and tabs
PM: domains: Drop/restore performance state votes for devices at runtime PM
PM: domains: Return early if perf state is already set for the device
PM: domains: Split code in dev_pm_genpd_set_performance_state()
cpuidle: teo: Use kerneldoc documentation in admin-guide
cpuidle: teo: Rework most recent idle duration values treatment
cpuidle: teo: Change the main idle state selection logic
cpuidle: teo: Cosmetic modification of teo_select()
cpuidle: teo: Cosmetic modifications of teo_update()
...
* pm-cpufreq:
cpufreq: Make cpufreq_online() call driver->offline() on errors
cpufreq: loongson2: Remove unused linux/sched.h headers
cpufreq: sh: Remove unused linux/sched.h headers
cpufreq: stats: Clean up local variable in cpufreq_stats_create_table()
cpufreq: intel_pstate: hybrid: Fix build with CONFIG_ACPI unset
cpufreq: sc520_freq: add 'fallthrough' to one case
cpufreq: intel_pstate: Add Cometlake support in no-HWP mode
cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode
cpufreq: intel_pstate: hybrid: CPU-specific scaling factor
cpufreq: intel_pstate: hybrid: Avoid exposing two global attributes
* pm-cpuidle:
cpuidle: teo: remove unneeded semicolon in teo_select()
cpuidle: teo: Use kerneldoc documentation in admin-guide
cpuidle: teo: Rework most recent idle duration values treatment
cpuidle: teo: Change the main idle state selection logic
cpuidle: teo: Cosmetic modification of teo_select()
cpuidle: teo: Cosmetic modifications of teo_update()
intel_idle: Adjust the SKX C6 parameters if PC6 is disabled
There are two descriptions of the TEO (Timer Events Oriented) cpuidle
governor in the kernel source tree, one in the C file containing its
code and one in cpuidle.rst which is part of admin-guide.
Instead of trying to keep them both in sync and in order to reduce
text duplication, include the governor description from the C file
directly into cpuidle.rst.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The turbo_pct and num_pstates sysfs attributes represent CPU
properties that may be different for differenty types of CPUs in
a hybrid processor, so avoid exposing them in that case.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are three files with replace macros for structs,
mapping them into Sphinx 2.x C domain references.
Well, this is broken on Sphinx 3.x. Also, for Sphinx 2.x,
the automarkup macro should be able to take care of them.
So, let's just drop those.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
* pm-cpuidle:
cpuidle: record state entry rejection statistics
cpuidle: psci: Allow PM domain to be initialized even if no OSI mode
firmware: psci: Extend psci_set_osi_mode() to allow reset to PC mode
ACPI: processor: Print more information when acpi_processor_evaluate_cst() fails
cpuidle: tegra: Correctly handle result of arm_cpuidle_simple_enter()
Fix a reStructuredText syntax error in the cpuidle PM admin-guide
documentation: the ``...'' quotation marks are parsed as partial ''...''
reStructuredText markup and break the output formatting.
This change them to "...".
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CPUs may fail to enter the chosen idle state if there was a
pending interrupt, causing the cpuidle driver to return an error
value.
Record that and export it via sysfs along with the other idle state
statistics.
This could prove useful in understanding behavior of the governor
and the system during usecases that involve multiple CPUs.
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
[ rjw: Changelog and documentation edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Modify the EPP sysfs interface to reject attempts to change the EPP
to values different from 0 ("performance") in the active mode with
the "performance" policy (ie. scaling_governor set to "performance"),
to avoid situations in which the kernel appears to discard data
passed to it via the EPP sysfs attribute.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Fix documentation build warning and sentence wording:
Documentation/admin-guide/pm/intel_pstate.rst:568: WARNING: Unexpected indentation.
Fixes: f473bf398b ("cpufreq: intel_pstate: Allow raw energy performance preference value")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Allow intel_pstate to work in the passive mode with HWP enabled and
make it set the HWP minimum performance limit (HWP floor) to the
P-state value given by the target frequency supplied by the cpufreq
governor, so as to prevent the HWP algorithm and the CPU scheduler
from working against each other, at least when the schedutil governor
is in use, and update the intel_pstate documentation accordingly.
Among other things, this allows utilization clamps to be taken
into account, at least to a certain extent, when intel_pstate is
in use and makes it more likely that sufficient capacity for
deadline tasks will be provided.
After this change, the resulting behavior of an HWP system with
intel_pstate in the passive mode should be close to the behavior
of the analogous non-HWP system with intel_pstate in the passive
mode, except that the HWP algorithm is generally allowed to make the
CPU run at a frequency above the floor P-state set by intel_pstate in
the entire available range of P-states, while without HWP a CPU can
run in a P-state above the requested one if the latter falls into the
range of turbo P-states (referred to as the turbo range) or if the
P-states of all CPUs in one package are coordinated with each other
at the hardware level.
[Note that in principle the HWP floor may not be taken into account
by the processor if it falls into the turbo range, in which case the
processor has a license to choose any P-state, either below or above
the HWP floor, just like a non-HWP processor in the case when the
target P-state falls into the turbo range.]
With this change applied, intel_pstate in the passive mode assumes
complete control over the HWP request MSR and concurrent changes of
that MSR (eg. via the direct MSR access interface) are overridden by
it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
while to come. Changes include:
- Some new Chinese translations
- Progress on the battle against double words words and non-HTTPS URLs
- Some block-mq documentation
- More RST conversions from Mauro. At this point, that task is
essentially complete, so we shouldn't see this kind of churn again for a
while. Unless we decide to switch to asciidoc or something...:)
- Lots of typo fixes, warning fixes, and more.
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Merge tag 'docs-5.9' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"It's been a busy cycle for documentation - hopefully the busiest for a
while to come. Changes include:
- Some new Chinese translations
- Progress on the battle against double words words and non-HTTPS
URLs
- Some block-mq documentation
- More RST conversions from Mauro. At this point, that task is
essentially complete, so we shouldn't see this kind of churn again
for a while. Unless we decide to switch to asciidoc or
something...:)
- Lots of typo fixes, warning fixes, and more"
* tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits)
scripts/kernel-doc: optionally treat warnings as errors
docs: ia64: correct typo
mailmap: add entry for <alobakin@marvell.com>
doc/zh_CN: add cpu-load Chinese version
Documentation/admin-guide: tainted-kernels: fix spelling mistake
MAINTAINERS: adjust kprobes.rst entry to new location
devices.txt: document rfkill allocation
PCI: correct flag name
docs: filesystems: vfs: correct flag name
docs: filesystems: vfs: correct sync_mode flag names
docs: path-lookup: markup fixes for emphasis
docs: path-lookup: more markup fixes
docs: path-lookup: fix HTML entity mojibake
CREDITS: Replace HTTP links with HTTPS ones
docs: process: Add an example for creating a fixes tag
doc/zh_CN: add Chinese translation prefer section
doc/zh_CN: add clearing-warn-once Chinese version
doc/zh_CN: add admin-guide index
doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label
futex: MAINTAINERS: Re-add selftests directory
...
Currently, the only way to specify the default CPUfreq governor is
via Kconfig options, which suits users who can build the kernel
themselves perfectly.
However, for those who use a distro-like kernel (such as Android,
with the Generic Kernel Image project), the only way to use a
non-default governor is to boot to userspace, and to then switch
using the sysfs interface. Being able to specify the default governor
on the command line, like is the case for cpuidle, would allow those
users to specify their governor of choice earlier on, and to simplify
the userspace boot procedure slighlty.
To support this use-case, add a kernel command line parameter
allowing the default governor for CPUfreq to be specified, which
takes precedence over the built-in default.
This implementation has one notable limitation: the default governor
must be registered before the driver. This is solved for builtin
governors and drivers using appropriate *_initcall() functions. And
in the modular case, this must be reflected as a constraint on the
module loading order.
Signed-off-by: Quentin Perret <qperret@google.com>
[ Viresh: Converted 'default_governor' to a string and parsing it only
at initcall level, and several updates to
cpufreq_init_policy(). ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently using attribute "energy_performance_preference", user space can
write one of the four per-defined preference string. These preference
strings gets mapped to a hard-coded Energy-Performance Preference (EPP) or
Energy-Performance Bias (EPB) knob.
These four values are supposed to cover broad spectrum of use cases, but
are not uniformly distributed in the range. There are number of cases,
where this is not enough. For example:
Suppose user wants more performance when connected to AC. Instead of using
default "balance performance", the "performance" setting can be used. This
changes EPP value from 0x80 to 0x00. But setting EPP to 0, results in
electrical and thermal issues on some platforms. This results in
aggressive throttling, which causes a drop in performance. But some value
between 0x80 and 0x00 results in better performance. But that value can't
be fixed as the power curve is not linear. In some cases just changing EPP
from 0x80 to 0x75 is enough to get significant performance gain.
Similarly on battery the default "balance_performance" mode can be
aggressive in power consumption. But picking up the next choice
"balance power" results in too much loss of performance, which results in
bad user experience in use cases like "Google Hangout". It was observed
that some value between these two EPP is optimal.
This change allows fine grain EPP tuning for platform like Chromebook or
for users who wants to fine tune power and performance.
Here based on the product and use cases, different EPP values can be set.
This change is similar to the change done for:
/sys/devices/system/cpu/cpu*/power/energy_perf_bias
where user has choice to write a predefined string or raw value.
The change itself is trivial. When user preference doesn't match
predefined string preferences and value is an unsigned integer and in
range, use that value for EPP. When the EPP feature is not present
writing raw value is not supported.
Suggested-by: Len Brown <lenb@kernel.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
By default intel_pstate the driver disables energy efficiency by setting
MSR_IA32_POWER_CTL bit 19 for Kaby Lake desktop CPU model in HWP mode.
This CPU model is also shared by Coffee Lake desktop CPUs. This allows
these systems to reach maximum possible frequency. But this adds power
penalty, which some customers don't want. They want some way to enable/
disable dynamically.
So, add an additional attribute "energy_efficiency" under
/sys/devices/system/cpu/intel_pstate/ for these CPU models. This allows
to read and write bit 19 ("Disable Energy Efficiency Optimization") in
the MSR IA32_POWER_CTL.
This attribute is present in both HWP and non-HWP mode as this has an
effect in both modes. Refer to Intel Software Developer's manual for
details.
The scope of this bit is package wide. Also these systems are single
package systems. So read/write MSR on the current CPU is enough.
The energy efficiency (EE) bit setting needs to be preserved during
suspend/resume and CPU offline/online operation. To do this:
- Restoring the EE setting from the cpufreq resume() callback, if there
is change from the system default.
- By default, don't disable EE from cpufreq init() callback for matching
CPU models. Since the scope is package wide and is a single package
system, move the disable EE calls from init() callback to
intel_pstate_init() function, which is called only once.
Suggested-by: Len Brown <lenb@kernel.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Added documentation to configure servers to use Intel(R) Speed
Select Technology using intel-speed-select tool.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Andriy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Update the document after the remove of cpuidle_sysfs_switch.
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After recent changes allowing scale-invariant utilization to be
used on x86, the schedutil governor on top of intel_pstate in the
passive mode should be on par with (or better than) the active mode
"powersave" algorithm of intel_pstate on systems in which
hardware-managed P-states (HWP) are not used, so it should not be
necessary to use the internal scaling algorithm in those cases.
Accordingly, modify intel_pstate to start in the passive mode by
default if the processor at hand does not support HWP of if the driver
is requested to avoid using HWP through the kernel command line.
Among other things, that will allow utilization clamps and the
support for RT/DL tasks in the schedutil governor to be utilized on
systems in which intel_pstate is used.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
URLs for presentation and Intel Software Developer’s Manual are updated
as they were using "http" which are gradually replaced by "https".
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are three legacy driver documents in Documentation/cpu-freq/
that were added years ago and converting them each to the .rst
format is rather pointless, even though there is some value in
preserving them. However, if they are preserved, they need to go
into the admin-guide part of cpufreq documentation where they belong
(at least to a certain extent).
To preserve them with minimum amount of changes and put them into the
right place, and make it possible to process them into HTML (and other
formats) along with the rest of the documentation, move them each
as a "literal text" block into a separate section of a single .rst
"wrapper" file under Documentation/admin-guide/pm/.
While at it, repair the PCC specification URL in one of them.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Update the PM QoS documentation to reflect the previous code changes
regarding the removal of PM QoS classes and the CPU latency QoS API
rework.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
Clean up the language in one paragraph in the PM QoS description in
Documentation/admin-guide/pm/cpuidle.rst.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is some information in Documentation/power/interface.rst that
is still missing from Documentation/admin-guide/pm/sleep-states.rst
and really should be present in there, so update the latter by
adding that information to it and delete the former (as it becomes
redundant after that and it is somewhat outdated).
While at it, clean up some assorted pieces of sleep-states.rst a bit.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In certain system configurations it may not be desirable to use some
C-states assumed to be available by intel_idle and the driver needs
to be prevented from using them even before the cpuidle sysfs
interface becomes accessible to user space. Currently, the only way
to achieve that is by setting the 'max_cstate' module parameter to a
value lower than the index of the shallowest of the C-states in
question, but that may be overly intrusive, because it effectively
makes all of the idle states deeper than the 'max_cstate' one go
away (and the C-state to avoid may be in the middle of the range
normally regarded as available).
To allow that limitation to be overcome, introduce a new module
parameter called 'states_off' to represent a list of idle states to
be disabled by default in the form of a bitmask and update the
documentation to cover it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For diagnostics, it is generally useful to be able to make intel_idle
take the system's ACPI tables into consideration even if that is not
required for the processor model in there, so introduce a new module
parameter, 'use_acpi', to make that happen and update the documentation
to cover it.
While at it, fix the 'no_acpi' module parameter name in the
documentation.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Scott Weaver
Waiman Long
David Arcari
Herton R. Krzesinski
Linus Torvalds
Rafael J. Wysocki
Mauro Carvalho Chehab
Andrew Klychkov
Julia Lawall
Yoann Congal
Lina Iyer
Randy Dunlap
Quentin Perret
Srinivas Pandruvada
Hanjun Guo
Alex Hung