The new epp support causes warnings about three separate
but related bugs:
1) failing before allocation should just return an error:
drivers/cpufreq/amd-pstate.c:951:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (!dev)
^~~~
drivers/cpufreq/amd-pstate.c:1018:9: note: uninitialized use occurs here
return ret;
^~~
2) wrong variable to store return code:
drivers/cpufreq/amd-pstate.c:963:6: error: variable 'ret' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (rc)
^~
drivers/cpufreq/amd-pstate.c:1019:9: note: uninitialized use occurs here
return ret;
^~~
drivers/cpufreq/amd-pstate.c:963:2: note: remove the 'if' if its condition is always false
if (rc)
^~~~~~~
3) calling amd_pstate_set_epp() in cleanup path after determining
that it should not be called:
drivers/cpufreq/amd-pstate.c:1055:6: error: variable 'epp' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (cpudata->epp_policy == cpudata->policy)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/cpufreq/amd-pstate.c:1080:30: note: uninitialized use occurs here
amd_pstate_set_epp(cpudata, epp);
^~~
All three are trivial to fix, but most likely there are additional bugs
in this function when the error handling was not really tested.
Fixes: ffa5096a7c ("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Reviewed-by: Yuan Perry <Perry.Yuan@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
All but a few drivers ignore the return value of
cpufreq_unregister_driver(). Those few that don't only call it after
cpufreq_register_driver() succeeded, in which case the call doesn't
fail.
Make the function return no value and add a WARN_ON for the case that
the function is called in an invalid situation (i.e. without a previous
successful call to cpufreq_register_driver()).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com> # brcmstb-avs-cpufreq.c
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
replace the sprintf with a more generic sysfs_emit function
No intended potential function impact
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@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>
While amd-pstate driver was loaded with specific driver mode, it will
need to check which mode is enabled for the pstate driver,add this sysfs
entry to show the current status
$ cat /sys/devices/system/cpu/amd-pstate/status
active
Meanwhile, user can switch the pstate driver mode with writing mode
string to sysfs entry as below.
Enable passive mode:
$ sudo bash -c "echo passive > /sys/devices/system/cpu/amd-pstate/status"
Enable active mode (EPP driver mode):
$ sudo bash -c "echo active > /sys/devices/system/cpu/amd-pstate/status"
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@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>
add suspend and resume support for the AMD processors by amd_pstate_epp
driver instance.
When the CPPC is suspended, EPP driver will set EPP profile to 'power'
profile and set max/min perf to lowest perf value.
When resume happens, it will restore the MSR registers with
previous cached value.
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <Mario.Limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@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>
Adds online and offline driver callback support to allow cpu cores go
offline and help to restore the previous working states when core goes
back online later for EPP driver mode.
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <Mario.Limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@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>
Add EPP driver support for AMD SoCs which support a dedicated MSR for
CPPC. EPP is used by the DPM controller to configure the frequency that
a core operates at during short periods of activity.
The SoC EPP targets are configured on a scale from 0 to 255 where 0
represents maximum performance and 255 represents maximum efficiency.
The amd-pstate driver exports profile string names to userspace that are
tied to specific EPP values.
The balance_performance string (0x80) provides the best balance for
efficiency versus power on most systems, but users can choose other
strings to meet their needs as well.
$ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences
default performance balance_performance balance_power power
$ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference
balance_performance
To enable the driver,it needs to add `amd_pstate=active` to kernel
command line and kernel will load the active mode epp driver
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <Mario.Limonciello@amd.com>
Reviewed-by: Wyes Karny <wyes.karny@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>
The amd-pstate driver may support multiple working modes.
Introduce a variable to keep track of which mode is currently enabled.
Here we use cppc_state var to indicate which mode is enabled.
This change will help to simplify the the amd_pstate_param() to choose
which mode used for the following driver registration.
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In the amd_pstate_adjust_perf(), there is one cpufreq_cpu_get() call to
increase increments the kobject reference count of policy and make it as
busy. Therefore, a corresponding call to cpufreq_cpu_put() is needed to
decrement the kobject reference count back, it will resolve the kernel
hang issue when unregistering the amd-pstate driver and register the
`amd_pstate_epp` driver instance.
Fixes: 1d215f0319 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Wyes Karny <wyes.karny@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Cc: 5.17+ <stable@vger.kernel.org> # 5.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When the amd_pstate driver is built-in users still need a method to be
able enable or disable it depending upon their circumstance.
Add support for an early parameter to do this.
There is some performance degradation on a number of ASICs in the
passive mode. This performance issue was originally discovered in
shared memory systems but it has been proven that certain workloads
on MSR systems also suffer performance issues.
Set the amd-pstate driver as disabled by default to temporarily
mitigate the performance problem.
1) with `amd_pstate=disable`, pstate driver will be disabled to load at
kernel booting.
2) with `amd_pstate=passive`, pstate driver will be enabled and loaded
as non-autonomous working mode supported in the low-level power
management firmware.
3) If neither parameter is specified, the driver will be disabled by
default to avoid triggering performance regressions in certain ASICs
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>
Currently when the amd-pstate and acpi_cpufreq are both built into
kernel as module driver, amd-pstate will not be loaded by default
in this case.
Change amd-pstate driver as built-in type, it will resolve the loading
sequence problem to allow user to make amd-pstate driver as the default
cpufreq scaling driver.
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>
Fixes: ec437d71db ("cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
MSR_AMD_PERF_CTL is guaranteed to be 0 on a cold boot. However, on a
kexec boot, for instance, it may have a non-zero value (if the cpu was
in a non-P0 Pstate). In such cases, the cores with non-P0 Pstates at
boot will never be pushed to P0, let alone boost frequencies.
Kexec is a common workflow for reboot on Linux and this creates a
regression in performance. Fix it by explicitly setting the
MSR_AMD_PERF_CTL to 0 during amd_pstate driver init.
Cc: All applicable <stable@vger.kernel.org>
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: 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>
This Kselftest update for Linux 6.1-rc1 consists of fixes and new tests.
- Adds a amd-pstate-ut test module, this module is used by kselftest
to unit test amd-pstate functionality
- Fixes and cleanups to to cpu-hotplug to delete the fault injection
test code
- Improvements to vm test to use top_srcdir for builds
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Merge tag 'linux-kselftest-next-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull Kselftest updates from Shuah Khan:
"Fixes and new tests:
- Add an amd-pstate-ut test module, used by kselftest to unit test
amd-pstate functionality
- Fixes and cleanups to to cpu-hotplug to delete the fault injection
test code
- Improvements to vm test to use top_srcdir for builds"
* tag 'linux-kselftest-next-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
docs:kselftest: fix kselftest_module.h path of example module
cpufreq: amd-pstate: Add explanation for X86_AMD_PSTATE_UT
selftests/cpu-hotplug: Add log info when test success
selftests/cpu-hotplug: Reserve one cpu online at least
selftests/cpu-hotplug: Delete fault injection related code
selftests/cpu-hotplug: Use return instead of exit
selftests/cpu-hotplug: Correct log info
cpufreq: amd-pstate: modify type in argument 2 for filp_open
Documentation: amd-pstate: Add unit test introduction
selftests: amd-pstate: Add test trigger for amd-pstate driver
cpufreq: amd-pstate: Add test module for amd-pstate driver
cpufreq: amd-pstate: Expose struct amd_cpudata
selftests/vm: use top_srcdir instead of recomputing relative paths
Expose struct amd_cpudata to AMD P-State unit test module.
This data struct will be used on the following AMD P-State unit test
(amd-pstate-ut) module. The amd-pstate-ut module can get some
AMD infomations by this data struct. For example: highest perf,
nominal perf, boost supported etc.
Signed-off-by: Meng Li <li.meng@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
- Add isupport for Tiger Lake in no-HWP mode to intel_pstate (Doug
Smythies).
- Update the AMD P-state driver (Perry Yuan):
* Fix wrong lowest perf fetch.
* Map desired perf into pstate scope for powersave governor.
* Update pstate frequency transition delay time.
* Fix initial highest_perf value.
* Clean up.
- Move max CPU capacity to sugov_policy in the schedutil cpufreq
governor (Lukasz Luba).
- Add SM6115 to cpufreq-dt blocklist (Adam Skladowski).
- Add support for Tegra239 and minor cleanups (Sumit Gupta, ye xingchen,
and Yang Yingliang).
- Add freq qos for qcom cpufreq driver and minor cleanups (Xuewen Yan,
and Viresh Kumar).
- Minor cleanups around functions called at module_init() (Xiu Jianfeng).
- Use module_init and add module_exit for bmips driver (Zhang Jianhua).
- Add AlderLake-N support to intel_idle (Zhang Rui).
- Replace strlcpy() with unused retval with strscpy() in intel_idle
(Wolfram Sang).
- Remove redundant check from cpuidle_switch_governor() (Yu Liao).
- Replace strlcpy() with unused retval with strscpy() in the powernv
cpuidle driver (Wolfram Sang).
- Drop duplicate word from a comment in the coupled cpuidle driver
(Jason Wang).
- Make rpm_resume() return -EINPROGRESS if RPM_NOWAIT is passed to it
in the flags and the device is about to resume (Rafael Wysocki).
- Add extra debugging statement for multiple active IRQs to system
wakeup handling code (Mario Limonciello).
- Replace strlcpy() with unused retval with strscpy() in the core
system suspend support code (Wolfram Sang).
- Update the intel_rapl power capping driver:
* Use standard Energy Unit for SPR Dram RAPL domain (Zhang Rui).
* Add support for RAPTORLAKE_S (Zhang Rui).
* Fix UBSAN shift-out-of-bounds issue (Chao Qin).
- Handle -EPROBE_DEFER when regulator is not probed on
mtk-ci-devfreq.c (AngeloGioacchino Del Regno).
- Fix message typo and use dev_err_probe() in rockchip-dfi.c
(Christophe JAILLET).
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Merge tag 'pm-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These add support for some new hardware, extend the existing hardware
support, fix some issues and clean up code
Specifics:
- Add isupport for Tiger Lake in no-HWP mode to intel_pstate (Doug
Smythies)
- Update the AMD P-state driver (Perry Yuan):
- Fix wrong lowest perf fetch
- Map desired perf into pstate scope for powersave governor
- Update pstate frequency transition delay time
- Fix initial highest_perf value
- Clean up
- Move max CPU capacity to sugov_policy in the schedutil cpufreq
governor (Lukasz Luba)
- Add SM6115 to cpufreq-dt blocklist (Adam Skladowski)
- Add support for Tegra239 and minor cleanups (Sumit Gupta, ye
xingchen, and Yang Yingliang)
- Add freq qos for qcom cpufreq driver and minor cleanups (Xuewen
Yan, and Viresh Kumar)
- Minor cleanups around functions called at module_init() (Xiu
Jianfeng)
- Use module_init and add module_exit for bmips driver (Zhang
Jianhua)
- Add AlderLake-N support to intel_idle (Zhang Rui)
- Replace strlcpy() with unused retval with strscpy() in intel_idle
(Wolfram Sang)
- Remove redundant check from cpuidle_switch_governor() (Yu Liao)
- Replace strlcpy() with unused retval with strscpy() in the powernv
cpuidle driver (Wolfram Sang)
- Drop duplicate word from a comment in the coupled cpuidle driver
(Jason Wang)
- Make rpm_resume() return -EINPROGRESS if RPM_NOWAIT is passed to it
in the flags and the device is about to resume (Rafael Wysocki)
- Add extra debugging statement for multiple active IRQs to system
wakeup handling code (Mario Limonciello)
- Replace strlcpy() with unused retval with strscpy() in the core
system suspend support code (Wolfram Sang)
- Update the intel_rapl power capping driver:
- Use standard Energy Unit for SPR Dram RAPL domain (Zhang Rui).
- Add support for RAPTORLAKE_S (Zhang Rui).
- Fix UBSAN shift-out-of-bounds issue (Chao Qin)
- Handle -EPROBE_DEFER when regulator is not probed on
mtk-ci-devfreq.c (AngeloGioacchino Del Regno)
- Fix message typo and use dev_err_probe() in rockchip-dfi.c
(Christophe JAILLET)"
* tag 'pm-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (29 commits)
cpufreq: qcom-cpufreq-hw: Add cpufreq qos for LMh
cpufreq: Add __init annotation to module init funcs
cpufreq: tegra194: change tegra239_cpufreq_soc to static
PM / devfreq: rockchip-dfi: Fix an error message
PM / devfreq: mtk-cci: Handle sram regulator probe deferral
powercap: intel_rapl: Use standard Energy Unit for SPR Dram RAPL domain
PM: runtime: Return -EINPROGRESS from rpm_resume() in the RPM_NOWAIT case
intel_idle: Add AlderLake-N support
powercap: intel_rapl: fix UBSAN shift-out-of-bounds issue
cpufreq: tegra194: Add support for Tegra239
cpufreq: qcom-cpufreq-hw: Fix uninitialized throttled_freq warning
cpufreq: intel_pstate: Add Tigerlake support in no-HWP mode
powercap: intel_rapl: Add support for RAPTORLAKE_S
cpufreq: amd-pstate: Fix initial highest_perf value
cpuidle: Remove redundant check in cpuidle_switch_governor()
PM: wakeup: Add extra debugging statement for multiple active IRQs
cpufreq: tegra194: Remove the unneeded result variable
PM: suspend: move from strlcpy() with unused retval to strscpy()
intel_idle: move from strlcpy() with unused retval to strscpy()
cpuidle: powernv: move from strlcpy() with unused retval to strscpy()
...
To avoid some new AMD processors use wrong highest perf when amd pstate
driver loaded, this fix will query the highest perf from MSR register
MSR_AMD_CPPC_CAP1 and cppc_acpi interface firstly, then compare with the
highest perf value got by calling amd_get_highest_perf() function.
The lower value will be the correct highest perf we need to use.
Otherwise the CPU max MHz will be incorrect if the
amd_get_highest_perf() did not cover the new process family and model ID.
Like this lscpu info, the max frequency is incorrect.
Vendor ID: AuthenticAMD
Socket(s): 1
Stepping: 2
CPU max MHz: 5410.0000
CPU min MHz: 400.0000
BogoMIPS: 5600.54
Fixes: 3743d55b28 (x86, sched: Fix the AMD CPPC maximum performance value on certain AMD Ryzen generations)
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Change the default transition latency to be 20ms that is more
reasonable transition delay for AMD processors in non-EPP driver mode.
Update transition delay time to 1ms, in the AMD CPU autonomous mode and
non-autonomous mode, CPPC firmware will decide frequency at 1ms timescale
based on the workload utilization.
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The patch will fix the invalid desired perf value for powersave
governor. This issue is found when testing on one AMD EPYC system, the
actual des_perf is smaller than the min_perf value, that is invalid
value. because the min_perf is the lowest_perf system can support in
idle state.
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix the wrong lowest perf value reading which is used for new
des_perf calculation by governor requested, the incorrect min_perf will
get incorrect des_perf to be set , that will cause the system frequency
changing unexpectedly.
Reviewed-by: Huang Rui <ray.huang@amd.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Su Jinzhou <jinzhou.su@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Remove the white space and correct mixed-up indentation
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
move the cpudata assignment to cpudata declaration which
will simplify the functions.
No functional change intended.
Reviewed-by: Huang Rui <ray.huang@amd.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Make acpi_cpc_valid() check if ACPI is disabled, so that its callers
don't need to check that separately. This will also cause the AMD
pstate driver to refuse to load right away when ACPI is disabled.
Also update the warning message in amd_pstate_init() to mention the
ACPI disabled case for completeness.
Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
[ rjw: Subject edits, new changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When system resumes from S3, the CPPC enable register will be
cleared and reset to 0.
So enable the CPPC interface by writing 1 to this register on
system resume and disable it during system suspend.
Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
[ rjw: Subject and changelog edits ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add frequency, mperf, aperf and tsc in the trace. This can be used
to debug and tune the performance of AMD P-state driver.
Use the time difference between amd_pstate_update to calculate CPU
frequency. There could be sleep in arch_freq_get_on_cpu, so do not
use it here.
Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Co-developed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add the description of @req and @boost_supported in struct amd_cpudata
kernel-doc comment to remove warnings found by running scripts/kernel-doc,
which is caused by using 'make W=1'.
drivers/cpufreq/amd-pstate.c:104: warning: Function parameter or member
'req' not described in 'amd_cpudata'
drivers/cpufreq/amd-pstate.c:104: warning: Function parameter or member
'boost_supported' not described in 'amd_cpudata'
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Introduce sysfs attributes to get the different level AMD P-State
performances.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Introduce sysfs attributes to get the different level processor
frequencies.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the sbios supports the boost mode of AMD P-State, let's switch to
boost enabled by default.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add trace event to monitor the performance value changes which is
controlled by cpu governors.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In some of Zen2 and Zen3 based processors, they are using the shared
memory that exposed from ACPI SBIOS. In this kind of the processors,
there is no MSR support, so we add acpi cppc function as the backend for
them.
It is using a module param (shared_mem) to enable related processors
manually. We will enable this by default once we address performance
issue on this solution.
Signed-off-by: Jinzhou Su <Jinzhou.Su@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Introduce the fast switch function for AMD P-State on the AMD processors
which support the full MSR register control. It's able to decrease the
latency on interrupt context.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
AMD P-State is the AMD CPU performance scaling driver that introduces a
new CPU frequency control mechanism on AMD Zen based CPU series in Linux
kernel. The new mechanism is based on Collaborative processor
performance control (CPPC) which is finer grain frequency management
than legacy ACPI hardware P-States. Current AMD CPU platforms are using
the ACPI P-states driver to manage CPU frequency and clocks with
switching only in 3 P-states. AMD P-State is to replace the ACPI
P-states controls, allows a flexible, low-latency interface for the
Linux kernel to directly communicate the performance hints to hardware.
AMD P-State leverages the Linux kernel governors such as *schedutil*,
*ondemand*, etc. to manage the performance hints which are provided by CPPC
hardware functionality. The first version for AMD P-State is to support one
of the Zen3 processors, and we will support more in future after we verify
the hardware and SBIOS functionalities.
There are two types of hardware implementations for AMD P-State: one is full
MSR support and another is shared memory support. It can use
X86_FEATURE_CPPC feature flag to distinguish the different types.
Using the new AMD P-State method + kernel governors (*schedutil*,
*ondemand*, ...) to manage the frequency update is the most appropriate
bridge between AMD Zen based hardware processor and Linux kernel, the
processor is able to adjust to the most efficiency frequency according to
the kernel scheduler loading.
Please check the detailed CPU feature and MSR register description in
Processor Programming Reference (PPR) for AMD Family 19h Model 51h,
Revision A1 Processors:
https://www.amd.com/system/files/TechDocs/56569-A1-PUB.zip
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Arnd Bergmann