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According to the description in the intel_pstate.rst documentation,
Capacity-Aware Scheduling and Energy-Aware Scheduling are only
supported on a hybrid processor without SMT. Previously, the system
used sched_smt_active() for judgment, which is not a strict condition
because users can switch it on or off via /sys at any time.
This could lead to incorrect driver settings in certain scenarios.
For example, on a CPU that supports SMT, a user can disable SMT
via the nosmt parameter to enable asym capacity, and then re-enable
SMT via /sys. In such cases, some settings in the driver would no
longer be correct.
To address this issue, replace sched_smt_active() with cpu_smt_possible(),
and only enable asym capacity when CPU SMT is not possible.
Fixes: 929ebc93ccaa ("cpufreq: intel_pstate: Set asymmetric CPU capacity on hybrid systems")
Signed-off-by: Yaxiong Tian <tianyaxiong@kylinos.cn>
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20260203024852.301066-1-tianyaxiong@kylinos.cn
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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To eliminate some code duplication from the intel_pstate driver,
move the core_get_val() function body to a new function called
get_perf_ctl_val() and make both core_get_val() and atom_get_val()
invoke it to carry out the same computation.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/2829273.mvXUDI8C0e@rafael.j.wysocki
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Use guard(mutex)(&intel_pstate_driver_lock), or the scoped variant of
it, wherever intel_pstate_driver_lock needs to be held.
This allows some local variables and goto statements to be dropped as
they are not necessary any more.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://patch.msgid.link/2807232.mvXUDI8C0e@rafael.j.wysocki
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Commit ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in
legacy mode") introduced a check for feature X86_FEATURE_IDA to verify
turbo mode support. Although this is the correct way to check for turbo
mode support, it causes issues on some platforms that disable turbo
during OS boot, but enable it later [1]. Before adding this feature
check, users were able to get turbo mode frequencies by writing 0 to
/sys/devices/system/cpu/intel_pstate/no_turbo post-boot.
To restore the old behavior on the affected systems while still
addressing the unchecked MSR issue on some Skylake-X systems, check
X86_FEATURE_IDA only immediately before updates of MSR_IA32_PERF_CTL
that may involve setting the Turbo Engage Bit (bit 32).
Fixes: ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode")
Reported-by: Aaron Rainbolt <arainbolt@kfocus.org>
Closes: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2122531 [1]
Tested-by: Aaron Rainbolt <arainbolt@kfocus.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject adjustment, changelog edits ]
Link: https://patch.msgid.link/20251111010840.141490-1-srinivas.pandruvada@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Prevent intel_pstate from loading when Out-of-Band (OOB) P-states mode
is enabled.
The OOB identification mechanism for Diamond Rapids servers is the same
as for prior generation CPUs such as Granite Rapids. Add the Diamond
Rapids CPU model to intel_pstate_cpu_oob_ids[] to ensure correct OOB
handling.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://patch.msgid.link/20251022215425.3566218-1-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Some debug messages generated by intel_pstate on a given hybrid system
are only printed for some CPUs which is confusing, so modify the driver
to print them for all CPUs. Also change those messages to avoid
printing local variable names in them.
Moreover, some debug messages printed by intel_pstate are quite hard
to understand without looking at the code printing them, so make them
somewhat clearer while at it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/8609836.T7Z3S40VBb@rafael.j.wysocki
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Instead of using HWP-to-frequency scaling factors for computing cost
coefficients in the energy model used on hybrid systems, which is
fragile, rely on CPU type information that is easily accessible now and
the information on whether or not L3 cache is present for this purpose.
This also allows the cost coefficients for P-cores to be adjusted so
that they start to be populated somewhat earlier (that is, before
E-cores are loaded up to their full capacity).
In addition to the above, replace an inaccurate comment regarding the
reason why the freq value is added to the cost in hybrid_get_cost().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Yaxiong Tian <tianyaxiong@kylinos.cn>
Link: https://patch.msgid.link/5932894.DvuYhMxLoT@rafael.j.wysocki
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Introduce a function for checking whether or not a given CPU has L3
cache, called hybrid_has_l3(), and use it in hybrid_get_cost() for
computing cost coefficients associated with a given perf domain.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/13884343.uLZWGnKmhe@rafael.j.wysocki
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Introduce a function for identifying the type of a given CPU in a
hybrid system, called hybrid_get_cpu_type(), and use if for hybrid
scaling factor determination in hwp_get_cpu_scaling().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/1954386.tdWV9SEqCh@rafael.j.wysocki
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The comment above the condition `if (cpu->last_sample_time)` clearly
indicates that the branch is taken for the vast majority of invocations
after the first sample in a cycle. The first sample is a one-time
initialization case.
Add likely() hint to the condition to improve branch prediction for
this performance-critical path in intel_pstate_sample().
Signed-off-by: Yaxiong Tian <tianyaxiong@kylinos.cn>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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So far, HWP has never been enabled without EPP (Energy-Performance
Preference) interface support, since the lack of the latter indicates an
incomplete implementation of HWP, which was the case on early development
vehicle platforms. However, HWP can be expected to work if DEC (Dynamic
Efficiency Control) is enabled as indicated by setting bit 27 in
MSR_IA32_POWER_CTL (DEC enable bit).
Accordingly, allow HWP to be enabled if the EPP interface is not
supported so long as DEC is enabled in the processor.
Still, the EPP control sysfs interface is useless when EPP is not
supported, so do not expose it in that case.
Link: https://lore.kernel.org/linux-pm/20250904000608.260817-2-srinivas.pandruvada@linux.intel.com/
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Co-developed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The intel_pstate driver manages CPU capacity changes itself and it does
not need an update of the capacity of all CPUs in the system to be
carried out after registering a PD.
Moreover, in some configurations (for instance, an SMT-capable
hybrid x86 system booted with nosmt in the kernel command line) the
em_check_capacity_update() call at the end of em_dev_register_perf_domain()
always fails and reschedules itself to run once again in 1 s, so
effectively it runs in vain every 1 s forever.
To address this, introduce a new variant of em_dev_register_perf_domain(),
called em_dev_register_pd_no_update(), that does not invoke
em_check_capacity_update(), and make intel_pstate use it instead of the
original.
Fixes: 7b010f9b9061 ("cpufreq: intel_pstate: EAS support for hybrid platforms")
Closes: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.com/
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Tested-by: Kenneth R. Crudup <kenny@panix.com>
Cc: 6.16+ <stable@vger.kernel.org> # 6.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Adjust frequency percentage computations in update_cpu_qos_request() to
avoid going above the exact numerical percentage in the FREQ_QOS_MAX
case.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Zihuan Zhang <zhangzihuan@kylinos.cn>
Link: https://patch.msgid.link/3395556.44csPzL39Z@rafael.j.wysocki
[ rjw: Rename "cpu" to "cpudata" and "cpunum" to "cpu" ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Move the code from the for_each_possible_cpu() loop in update_qos_request()
to a separate function and use __free() for cpufreq policy reference
counting in it to avoid having to call cpufreq_cpu_put() repeatedly (or
using goto).
While at it, rename update_qos_request() to update_qos_requests()
because it updates multiple requests in one go.
No intentional functional impact.
Link: https://lore.kernel.org/linux-pm/CAJZ5v0gN1T5woSF0tO=TbAh+2-sWzxFjWyDbB7wG2TFCOU01iQ@mail.gmail.com/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Zihuan Zhang <zhangzihuan@kylinos.cn>
Link: https://patch.msgid.link/3026597.e9J7NaK4W3@rafael.j.wysocki
[ rjw: Rename "cpu" to "cpudata" and "cpunum" to "cpu" in new code ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq_cpu_put() call in update_qos_request() takes place too early
because the latter subsequently calls freq_qos_update_request() that
indirectly accesses the policy object in question through the QoS request
object passed to it.
Fortunately, update_qos_request() is called under intel_pstate_driver_lock,
so this issue does not matter for changing the intel_pstate operation
mode, but it theoretically can cause a crash to occur on CPU device hot
removal (which currently can only happen in virt, but it is formally
supported nevertheless).
Address this issue by modifying update_qos_request() to drop the
reference to the policy later.
Fixes: da5c504c7aae ("cpufreq: intel_pstate: Implement QoS supported freq constraints")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Zihuan Zhang <zhangzihuan@kylinos.cn>
Link: https://patch.msgid.link/2255671.irdbgypaU6@rafael.j.wysocki
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The intel_pstate driver does not enable HWP mode when CPUID.06H:EAX[10]
is not set, indicating that EPP (Energy Performance Preference) is not
supported by the hardware.
When EPP is unavailable, the system falls back to using EPB (Energy
Performance Bias) if the feature is supported. However, since the
intel_pstate driver will not enable HWP in this scenario, any EPB-related
code becomes unreachable and irrelevant. Remove the EPB handling code
paths simplifying the driver logic and reducing code size.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20250904000608.260817-1-srinivas.pandruvada@linux.intel.com
[ rjw: Subject adjustment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Follow cleanup.h recommendations and define and assign a variable
in one statement when __free() is used.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Zihuan Zhang <zhangzihuan@kylinos.cn>
Link: https://patch.msgid.link/2251447.irdbgypaU6@rafael.j.wysocki
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Prevent intel_pstate from loading when OOB (Out Of Band) P-states mode is
enabled.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20250808145122.4057208-1-srinivas.pandruvada@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Users may disable HWP in firmware, in which case intel_pstate
wouldn't load unless the CPU model is explicitly supported.
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://patch.msgid.link/20250623105601.3924-1-lirongqing@baidu.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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In the passive mode, intel_cpufreq_update_pstate() sets HWP_MIN_PERF in
accordance with the target frequency to ensure delivering adequate
performance, but it sets HWP_DESIRED_PERF to 0, so the processor has no
indication that the desired performance level is actually equal to the
floor one. This may cause it to choose a performance point way above
the desired level.
Moreover, this is inconsistent with intel_cpufreq_adjust_perf() which
actually sets HWP_DESIRED_PERF in accordance with the target performance
value.
Address this by adjusting intel_cpufreq_update_pstate() to pass
target_pstate as both the minimum and the desired performance levels
to intel_cpufreq_hwp_update().
Fixes: a365ab6b9dfb ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Shashank Balaji <shashank.mahadasyam@sony.com>
Link: https://patch.msgid.link/6173276.lOV4Wx5bFT@rjwysocki.net
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"Once again, the changes are dominated by cpufreq updates, but this
time the majority of them are cpufreq core changes, mostly related to
the introduction of policy locking guards and __free() usage, and
fixes related to boost handling.
Still, there is also a significant update of the intel_pstate driver
making it register an energy model when running on a hybrid platform
which is used for enabling energy-aware scheduling (EAS) if the driver
operates in the passive mode (and schedutil is used as the cpufreq
governor for all CPUs which is the passive mode default).
There are some amd-pstate driver updates too, for a good measure,
including the "Requested CPU Min frequency" BIOS option support and
new online/offline callbacks.
In the cpuidle space, the most significant change is the addition of a
C1 demotion on/off sysfs knob to intel_idle which should help some
users to configure their systems more precisely. There is also the
conversion of the PSCI cpuidle driver to a faux device one and there
are two small updates of cpuidle governors.
Device power management is also modified quite a bit, especially the
handling of devices with asynchronous suspend and resume enabled
during system transitions. They are now going to be handled more
asynchronously during suspend transitions and somewhat less
aggressively during resume transitions.
Apart from the above, the operating performance points (OPP) library
is now going to use mutex locking guards and scope-based cleanup
helpers and there is the usual bunch of assorted fixes and code
cleanups.
Specifics:
- Fix potential division-by-zero error in em_compute_costs() (Yaxiong
Tian)
- Fix typos in energy model documentation and example driver code
(Moon Hee Lee, Atul Kumar Pant)
- Rearrange the energy model management code and add a new function
for adjusting a CPU energy model after adjusting the capacity of
the given CPU to it (Rafael Wysocki)
- Refactor cpufreq_online(), add and use cpufreq policy locking
guards, use __free() in policy reference counting, and clean up
core cpufreq code on top of that (Rafael Wysocki)
- Fix boost handling on CPU suspend/resume and sysfs updates (Viresh
Kumar)
- Fix des_perf clamping with max_perf in amd_pstate_update()
(Dhananjay Ugwekar)
- Add offline, online and suspend callbacks to the amd-pstate driver,
rename and use the existing amd_pstate_epp callbacks in it
(Dhananjay Ugwekar)
- Add support for the "Requested CPU Min frequency" BIOS option to
the amd-pstate driver (Dhananjay Ugwekar)
- Reset amd-pstate driver mode after running selftests (Swapnil
Sapkal)
- Avoid shadowing ret in amd_pstate_ut_check_driver() (Nathan
Chancellor)
- Add helper for governor checks to the schedutil cpufreq governor
and move cpufreq-specific EAS checks to cpufreq (Rafael Wysocki)
- Populate the cpu_capacity sysfs entries from the intel_pstate
driver after registering asym capacity support (Ricardo Neri)
- Add support for enabling Energy-aware scheduling (EAS) to the
intel_pstate driver when operating in the passive mode on a hybrid
platform (Rafael Wysocki)
- Drop redundant cpus_read_lock() from store_local_boost() in the
cpufreq core (Seyediman Seyedarab)
- Replace sscanf() with kstrtouint() in the cpufreq code and use a
symbol instead of a raw number in it (Bowen Yu)
- Add support for autonomous CPU performance state selection to the
CPPC cpufreq driver (Lifeng Zheng)
- OPP: Add dev_pm_opp_set_level() (Praveen Talari)
- Introduce scope-based cleanup headers and mutex locking guards in
OPP core (Viresh Kumar)
- Switch OPP to use kmemdup_array() (Zhang Enpei)
- Optimize bucket assignment when next_timer_ns equals KTIME_MAX in
the menu cpuidle governor (Zhongqiu Han)
- Convert the cpuidle PSCI driver to a faux device one (Sudeep Holla)
- Add C1 demotion on/off sysfs knob to the intel_idle driver (Artem
Bityutskiy)
- Fix typos in two comments in the teo cpuidle governor (Atul Kumar
Pant)
- Fix denying of auto suspend in pm_suspend_timer_fn() (Charan Teja
Kalla)
- Move debug runtime PM attributes to runtime_attrs[] (Rafael
Wysocki)
- Add new devm_ functions for enabling runtime PM and runtime PM
reference counting (Bence Csókás)
- Remove size arguments from strscpy() calls in the hibernation core
code (Thorsten Blum)
- Adjust the handling of devices with asynchronous suspend enabled
during system suspend and resume to start resuming them immediately
after resuming their parents and to start suspending such a device
immediately after suspending its first child (Rafael Wysocki)
- Adjust messages printed during tasks freezing to avoid using
pr_cont() (Andrew Sayers, Paul Menzel)
- Clean up unnecessary usage of !! in pm_print_times_init() (Zihuan
Zhang)
- Add missing wakeup source attribute relax_count to sysfs and remove
the space character at the end ofi the string produced by
pm_show_wakelocks() (Zijun Hu)
- Add configurable pm_test delay for hibernation (Zihuan Zhang)
- Disable asynchronous suspend in ucsi_ccg_probe() to prevent the
cypd4226 device on Tegra boards from suspending prematurely (Jon
Hunter)
- Unbreak printing PM debug messages during hibernation and clean up
some related code (Rafael Wysocki)
- Add a systemd service to run cpupower and change cpupower binding's
Makefile to use -lcpupower (John B. Wyatt IV, Francesco Poli)"
* tag 'pm-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (72 commits)
cpufreq: CPPC: Add support for autonomous selection
cpufreq: Update sscanf() to kstrtouint()
cpufreq: Replace magic number
OPP: switch to use kmemdup_array()
PM: freezer: Rewrite restarting tasks log to remove stray *done.*
PM: runtime: fix denying of auto suspend in pm_suspend_timer_fn()
cpufreq: drop redundant cpus_read_lock() from store_local_boost()
cpupower: do not install files to /etc/default/
cpupower: do not call systemctl at install time
cpupower: do not write DESTDIR to cpupower.service
PM: sleep: Introduce pm_sleep_transition_in_progress()
cpufreq/amd-pstate: Avoid shadowing ret in amd_pstate_ut_check_driver()
cpufreq: intel_pstate: Document hybrid processor support
cpufreq: intel_pstate: EAS: Increase cost for CPUs using L3 cache
cpufreq: intel_pstate: EAS support for hybrid platforms
PM: EM: Introduce em_adjust_cpu_capacity()
PM: EM: Move CPU capacity check to em_adjust_new_capacity()
PM: EM: Documentation: Fix typos in example driver code
cpufreq: Drop policy locking from cpufreq_policy_is_good_for_eas()
PM: sleep: Introduce pm_suspend_in_progress()
...
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On some hybrid platforms some efficient CPUs (E-cores) are not connected
to the L3 cache, but there are no other differences between them and the
other E-cores that use L3. In that case, it is generally more efficient
to run "light" workloads on the E-cores that do not use L3 and allow all
of the cores using L3, including P-cores, to go into idle states.
For this reason, slightly increase the cost for all CPUs sharing the L3
cache to make EAS prefer CPUs that do not use it to the other CPUs of
the same type (if any).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/2032776.usQuhbGJ8B@rjwysocki.net
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Modify intel_pstate to register EM perf domains for CPUs on hybrid
platforms without SMT which causes EAS to be enabled on them when
schedutil is used as the cpufreq governor (which requires intel_pstate
to operate in the passive mode).
This change is targeting platforms (for example, Lunar Lake) where the
"little" CPUs (E-cores) are always more energy-efficient than the "big"
or "performance" CPUs (P-cores) when run at the same HWP performance
level, so it is sufficient to tell EAS that E-cores are always preferred
(so long as there is enough spare capacity on one of them to run the
given task). However, migrating tasks between CPUs of the same type
too often is not desirable because it may hurt both performance and
energy efficiency due to leaving warm caches behind.
For this reason, register a separate perf domain for each CPU and choose
the cost values for them so that the cost mostly depends on the CPU type,
but there is also a small component of it depending on the performance
level (utilization) which helps to balance the load between CPUs of the
same type.
The cost component related to the CPU type is computed with the help of
the observation that the IPC metric value for a given CPU is inversely
proportional to its performance-to-frequency scaling factor and the cost
of running code on it can be assumed to be roughly proportional to that
IPC ratio (in principle, the higher the IPC ratio, the more resources
are utilized when running at a given frequency, so the cost should be
higher).
For all CPUs that are online at the system initialization time, EM perf
domains are registered when the driver starts up, after asymmetric
capacity support has been enabled. For the CPUs that become online
later, EM perf domains are registered after setting the asymmetric
capacity for them.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://patch.msgid.link/6057101.MhkbZ0Pkbq@rjwysocki.net
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Intel hybrid processors have CPUs of different capacity. Populate the
interface /sys/devices/system/cpu/cpuN/cpu_capacity.
This interface uses the per-CPU variable `cpu_scale`. On x86 this
variable has no other use besides feeding the sysfs entries. Initialize
it when setting CPU capacity for the scheduler and scale-invariant code.
Feed it with arch_scale_cpu_capacity() as it gives capacity normalized
to the interval [0, SCHED_CAPACITY_SCALE].
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Conflicts:
drivers/cpufreq/intel_pstate.c
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When turbo mode is unavailable on a Skylake-X system, executing the
command:
# echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo
results in an unchecked MSR access error:
WRMSR to 0x199 (attempted to write 0x0000000100001300).
This issue was reproduced on an OEM (Original Equipment Manufacturer)
system and is not a common problem across all Skylake-X systems.
This error occurs because the MSR 0x199 Turbo Engage Bit (bit 32) is set
when turbo mode is disabled. The issue arises when intel_pstate fails to
detect that turbo mode is disabled. Here intel_pstate relies on
MSR_IA32_MISC_ENABLE bit 38 to determine the status of turbo mode.
However, on this system, bit 38 is not set even when turbo mode is
disabled.
According to the Intel Software Developer's Manual (SDM), the BIOS sets
this bit during platform initialization to enable or disable
opportunistic processor performance operations. Logically, this bit
should be set in such cases. However, the SDM also specifies that "OS
and applications must use CPUID leaf 06H to detect processors with
opportunistic processor performance operations enabled."
Therefore, in addition to checking MSR_IA32_MISC_ENABLE bit 38, verify
that CPUID.06H:EAX[1] is 0 to accurately determine if turbo mode is
disabled.
Fixes: 4521e1a0ce17 ("cpufreq: intel_pstate: Reflect current no_turbo state correctly")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Commit b52aaeeadfac ("cpufreq: intel_pstate: Avoid SMP calls to get
cpu-type") introduced two issues into hwp_get_cpu_scaling(). First,
it made that function use the CPU type of the CPU running the code
even though the target CPU is passed as the argument to it and second,
it used smp_processor_id() for that even though hwp_get_cpu_scaling()
runs in preemptible context.
Fix both of these problems by simply passing "cpu" to cpu_data().
Fixes: b52aaeeadfac ("cpufreq: intel_pstate: Avoid SMP calls to get cpu-type")
Link: https://lore.kernel.org/linux-pm/20250412103434.5321-1-xry111@xry111.site/
Reported-by: Xi Ruoyao <xry111@xry111.site>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/12659608.O9o76ZdvQC@rjwysocki.net
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Xin Li <xin@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Since cpufreq_update_limits() obtains a cpufreq policy pointer for the
given CPU and reference counts the corresponding policy object, it may
as well pass the policy pointer to the cpufreq driver's ->update_limits()
callback which allows that callback to avoid invoking cpufreq_cpu_get()
for the same CPU.
Accordingly, redefine ->update_limits() to take a policy pointer instead
of a CPU number and update both drivers implementing it, intel_pstate
and amd-pstate, as needed.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://patch.msgid.link/8560367.NyiUUSuA9g@rjwysocki.net
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Rename __intel_pstate_update_max_freq() to intel_pstate_update_max_freq()
and move the cpufreq policy reference counting and locking into it (and
implement the locking with the recently introduced cpufreq policy "write"
locking guard).
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/2315023.iZASKD2KPV@rjwysocki.net
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These are dominated by cpufreq updates which in turn are dominated by
updates related to boost support in the core and drivers and
amd-pstate driver optimizations.
Apart from the above, there are some cpuidle updates including a
rework of the most recent idle intervals handling in the venerable
menu governor that leads to significant improvements in some
performance benchmarks, as the governor is now more likely to predict
a shorter idle duration in some cases, and there are updates of the
core device power management code, mostly related to system suspend
and resume, that should help to avoid potential issues arising when
the drivers of devices depending on one another want to use different
optimizations.
There is also a usual collection of assorted fixes and cleanups,
including removal of some unused code.
Specifics:
- Manage sysfs attributes and boost frequencies efficiently from
cpufreq core to reduce boilerplate code in drivers (Viresh Kumar)
- Minor cleanups to cpufreq drivers (Aaron Kling, Benjamin Schneider,
Dhananjay Ugwekar, Imran Shaik, zuoqian)
- Migrate some cpufreq drivers to using for_each_present_cpu() (Jacky
Bai)
- cpufreq-qcom-hw DT binding fixes (Krzysztof Kozlowski)
- Use str_enable_disable() helper in cpufreq_online() (Lifeng Zheng)
- Optimize the amd-pstate driver to avoid cases where call paths end
up calling the same writes multiple times and needlessly caching
variables through code reorganization, locking overhaul and tracing
adjustments (Mario Limonciello, Dhananjay Ugwekar)
- Make it possible to avoid enabling capacity-aware scheduling (CAS)
in the intel_pstate driver and relocate a check for out-of-band
(OOB) platform handling in it to make it detect OOB before checking
HWP availability (Rafael Wysocki)
- Fix dbs_update() to avoid inadvertent conversions of negative
integer values to unsigned int which causes CPU frequency selection
to be inaccurate in some cases when the "conservative" cpufreq
governor is in use (Jie Zhan)
- Update the handling of the most recent idle intervals in the menu
cpuidle governor to prevent useful information from being discarded
by it in some cases and improve the prediction accuracy (Rafael
Wysocki)
- Make it possible to tell the intel_idle driver to ignore its
built-in table of idle states for the given processor, clean up the
handling of auto-demotion disabling on Baytrail and Cherrytrail
chips in it, and update its MAINTAINERS entry (David Arcari, Artem
Bityutskiy, Rafael Wysocki)
- Make some cpuidle drivers use for_each_present_cpu() instead of
for_each_possible_cpu() during initialization to avoid issues
occurring when nosmp or maxcpus=0 are used (Jacky Bai)
- Clean up the Energy Model handling code somewhat (Rafael Wysocki)
- Use kfree_rcu() to simplify the handling of runtime Energy Model
updates (Li RongQing)
- Add an entry for the Energy Model framework to MAINTAINERS as
properly maintained (Lukasz Luba)
- Address RCU-related sparse warnings in the Energy Model code
(Rafael Wysocki)
- Remove ENERGY_MODEL dependency on SMP and allow it to be selected
when DEVFREQ is set without CPUFREQ so it can be used on a wider
range of systems (Jeson Gao)
- Unify error handling during runtime suspend and runtime resume in
the core to help drivers to implement more consistent runtime PM
error handling (Rafael Wysocki)
- Drop a redundant check from pm_runtime_force_resume() and rearrange
documentation related to __pm_runtime_disable() (Rafael Wysocki)
- Rework the handling of the "smart suspend" driver flag in the PM
core to avoid issues hat may occur when drivers using it depend on
some other drivers and clean up the related PM core code (Rafael
Wysocki, Colin Ian King)
- Fix the handling of devices with the power.direct_complete flag set
if device_suspend() returns an error for at least one device to
avoid situations in which some of them may not be resumed (Rafael
Wysocki)
- Use mutex_trylock() in hibernate_compressor_param_set() to avoid a
possible deadlock that may occur if the "compressor" hibernation
module parameter is accessed during the registration of a new
ieee80211 device (Lizhi Xu)
- Suppress sleeping parent warning in device_pm_add() in the case
when new children are added under a device with the
power.direct_complete set after it has been processed by
device_resume() (Xu Yang)
- Remove needless return in three void functions related to system
wakeup (Zijun Hu)
- Replace deprecated kmap_atomic() with kmap_local_page() in the
hibernation core code (David Reaver)
- Remove unused helper functions related to system sleep (David Alan
Gilbert)
- Clean up s2idle_enter() so it does not lock and unlock CPU offline
in vain and update comments in it (Ulf Hansson)
- Clean up broken white space in dpm_wait_for_children() (Geert
Uytterhoeven)
- Update the cpupower utility to fix lib version-ing in it and memory
leaks in error legs, remove hard-coded values, and implement CPU
physical core querying (Thomas Renninger, John B. Wyatt IV, Shuah
Khan, Yiwei Lin, Zhongqiu Han)"
* tag 'pm-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (139 commits)
PM: sleep: Fix bit masking operation
dt-bindings: cpufreq: cpufreq-qcom-hw: Narrow properties on SDX75, SA8775p and SM8650
dt-bindings: cpufreq: cpufreq-qcom-hw: Drop redundant minItems:1
dt-bindings: cpufreq: cpufreq-qcom-hw: Add missing constraint for interrupt-names
dt-bindings: cpufreq: cpufreq-qcom-hw: Add QCS8300 compatible
cpufreq: Init cpufreq only for present CPUs
PM: sleep: Fix handling devices with direct_complete set on errors
cpuidle: Init cpuidle only for present CPUs
PM: clk: Remove unused pm_clk_remove()
PM: sleep: core: Fix indentation in dpm_wait_for_children()
PM: s2idle: Extend comment in s2idle_enter()
PM: s2idle: Drop redundant locks when entering s2idle
PM: sleep: Remove unused pm_generic_ wrappers
cpufreq: tegra186: Share policy per cluster
cpupower: Make lib versioning scheme more obvious and fix version link
PM: EM: Rework the depends on for CONFIG_ENERGY_MODEL
PM: EM: Address RCU-related sparse warnings
cpupower: Implement CPU physical core querying
pm: cpupower: remove hard-coded topology depth values
pm: cpupower: Fix cmd_monitor() error legs to free cpu_topology
...
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Intel pstate driver relies on SMP calls to get the cpu-type of a given CPU.
Remove the SMP calls and instead use the cached value of cpu-type which is
more efficient.
[ mingo: Forward ported it. ]
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20241211-add-cpu-type-v5-2-2ae010f50370@linux.intel.com
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Move the invocation of intel_pstate_platform_pwr_mgmt_exists() before
checking whether or not HWP is enabled because it does not depend on
any code running before it except for the vendor check and if CPU
performance scaling is going to be carried out by the platform, all of
the code that runs before that function (again, except for the vendor
check) is redundant.
This is not expected to alter any functionality except for the ordering
of messages printed by intel_pstate_init() when it is going to return an
error before attempting to register the driver.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/2776745.mvXUDI8C0e@rjwysocki.net
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Capacity-aware scheduling (CAS) is enabled by default by intel_pstate on
hybrid systems without SMT, but in some usage scenarios it may be more
attractive to place tasks for maximum CPU performance regardless of the
extra cost in terms of energy, which is the case on such systems when
CAS is not enabled, so introduce a command line option to forbid
intel_pstate to enable CAS.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by:Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/2781262.mvXUDI8C0e@rjwysocki.net
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epp_policy uses the same values as cpufreq_policy.policy and resets
to CPUFREQ_POLICY_UNKNOWN during offlining. Be consistent about
it and initialize to CPUFREQ_POLICY_UNKNOWN instead of 0, too.
No functional change intended.
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20241211122605.3048503-3-christian.loehle@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Since HYBRID_SCALING_FACTOR_MTL is not going to be suitable for Arrow
Lake in general, drop it from the "known hybrid scaling factors" list of
platforms, so the scaling factor for it will be determined with the
help of information provided by the platform firmware via CPPC.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/2307515.iZASKD2KPV@rjwysocki.net
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The perf-to-frequency scaling factors are used by intel_pstate on hybrid
platforms to cast performance levels to frequency on different types of
CPUs which is needed because the generic cpufreq sysfs interface works
in the frequency domain.
For some hybrid platforms already in the field, the scaling factors are
known, but for others (including some upcoming ones) they most likely
will be different and the only way to get them that scales is to use
information provided by the platform firmware. In this particular case,
the requisite information can be obtained via CPPC.
If the P-core hybrid scaling factor for the given processor model is not
known, use CPPC to compute hybrid scaling factors for all CPUs.
Since the current default hybrid scaling factor is only suitable for a
few early hybrid platforms, add intel_hybrid_scaling_factor[] entries
for them and initialize the scaling factor to zero ("unknown") by
default.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/8476313.T7Z3S40VBb@rjwysocki.net
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Update EPP default for balance_performance to 32.
This will give better performance out of the box using Intel P-State
powersave governor while still offering power savings compared to
performance governor.
This is in line with what has already been done for Emerald Rapids and
Sapphire Rapids.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20241112235946.368082-1-srinivas.pandruvada@linux.intel.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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