diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/acpi/cppc_sysfs.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/cifs/usage.rst | 7 | ||||
| -rw-r--r-- | Documentation/admin-guide/devices.txt | 8 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 104 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-per-CPU-kthreads.rst | 2 | ||||
| -rw-r--r-- | Documentation/admin-guide/media/platform-cardlist.rst | 1 | ||||
| -rw-r--r-- | Documentation/admin-guide/perf/hisi-pcie-pmu.rst | 106 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/amd-pstate.rst | 382 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/working-state.rst | 1 | ||||
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 11 |
10 files changed, 588 insertions, 36 deletions
diff --git a/Documentation/admin-guide/acpi/cppc_sysfs.rst b/Documentation/admin-guide/acpi/cppc_sysfs.rst index fccf22114e85..e53d76365aa7 100644 --- a/Documentation/admin-guide/acpi/cppc_sysfs.rst +++ b/Documentation/admin-guide/acpi/cppc_sysfs.rst @@ -4,6 +4,8 @@ Collaborative Processor Performance Control (CPPC) ================================================== +.. _cppc_sysfs: + CPPC ==== diff --git a/Documentation/admin-guide/cifs/usage.rst b/Documentation/admin-guide/cifs/usage.rst index f170d8820258..3766bf8a1c20 100644 --- a/Documentation/admin-guide/cifs/usage.rst +++ b/Documentation/admin-guide/cifs/usage.rst @@ -734,10 +734,9 @@ SecurityFlags Flags which control security negotiation and using weaker password hashes is 0x37037 (lanman, plaintext, ntlm, ntlmv2, signing allowed). Some SecurityFlags require the corresponding menuconfig - options to be enabled (lanman and plaintext require - CONFIG_CIFS_WEAK_PW_HASH for example). Enabling - plaintext authentication currently requires also - enabling lanman authentication in the security flags + options to be enabled. Enabling plaintext + authentication currently requires also enabling + lanman authentication in the security flags because the cifs module only supports sending laintext passwords using the older lanman dialect form of the session setup SMB. (e.g. for authentication diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt index 922c23bb4372..c07dc0ee860e 100644 --- a/Documentation/admin-guide/devices.txt +++ b/Documentation/admin-guide/devices.txt @@ -2339,13 +2339,7 @@ disks (see major number 3) except that the limit on partitions is 31. - 162 char Raw block device interface - 0 = /dev/rawctl Raw I/O control device - 1 = /dev/raw/raw1 First raw I/O device - 2 = /dev/raw/raw2 Second raw I/O device - ... - max minor number of raw device is set by kernel config - MAX_RAW_DEVS or raw module parameter 'max_raw_devs' + 162 char Used for (now removed) raw block device interface 163 char diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 9725c546a0d4..685645e75706 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -225,14 +225,23 @@ For broken nForce2 BIOS resulting in XT-PIC timer. acpi_sleep= [HW,ACPI] Sleep options - Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, - old_ordering, nonvs, sci_force_enable, nobl } + Format: { s3_bios, s3_mode, s3_beep, s4_hwsig, + s4_nohwsig, old_ordering, nonvs, + sci_force_enable, nobl } See Documentation/power/video.rst for information on s3_bios and s3_mode. s3_beep is for debugging; it makes the PC's speaker beep as soon as the kernel's real-mode entry point is called. + s4_hwsig causes the kernel to check the ACPI hardware + signature during resume from hibernation, and gracefully + refuse to resume if it has changed. This complies with + the ACPI specification but not with reality, since + Windows does not do this and many laptops do change it + on docking. So the default behaviour is to allow resume + and simply warn when the signature changes, unless the + s4_hwsig option is enabled. s4_nohwsig prevents ACPI hardware signature from being - used during resume from hibernation. + used (or even warned about) during resume. old_ordering causes the ACPI 1.0 ordering of the _PTS control method, with respect to putting devices into low power states, to be enforced (the ACPI 2.0 ordering @@ -1689,6 +1698,8 @@ architectures force reset to be always executed i8042.unlock [HW] Unlock (ignore) the keylock i8042.kbdreset [HW] Reset device connected to KBD port + i8042.probe_defer + [HW] Allow deferred probing upon i8042 probe errors i810= [HW,DRM] @@ -2413,8 +2424,12 @@ Default is 1 (enabled) kvm-intel.emulate_invalid_guest_state= - [KVM,Intel] Enable emulation of invalid guest states - Default is 0 (disabled) + [KVM,Intel] Disable emulation of invalid guest state. + Ignored if kvm-intel.enable_unrestricted_guest=1, as + guest state is never invalid for unrestricted guests. + This param doesn't apply to nested guests (L2), as KVM + never emulates invalid L2 guest state. + Default is 1 (enabled) kvm-intel.flexpriority= [KVM,Intel] Disable FlexPriority feature (TPR shadow). @@ -2934,7 +2949,7 @@ both parameters are enabled, hugetlb_free_vmemmap takes precedence over memory_hotplug.memmap_on_memory. - memtest= [KNL,X86,ARM,PPC,RISCV] Enable memtest + memtest= [KNL,X86,ARM,M68K,PPC,RISCV] Enable memtest Format: <integer> default : 0 <disable> Specifies the number of memtest passes to be @@ -3545,6 +3560,13 @@ shutdown the other cpus. Instead use the REBOOT_VECTOR irq. + nomodeset Disable kernel modesetting. DRM drivers will not perform + display-mode changes or accelerated rendering. Only the + system framebuffer will be available for use if this was + set-up by the firmware or boot loader. + + Useful as fallback, or for testing and debugging. + nomodule Disable module load nopat [X86] Disable PAT (page attribute table extension of @@ -4343,19 +4365,30 @@ Disable the Correctable Errors Collector, see CONFIG_RAS_CEC help text. - rcu_nocbs= [KNL] - The argument is a cpu list, as described above. - - In kernels built with CONFIG_RCU_NOCB_CPU=y, set - the specified list of CPUs to be no-callback CPUs. - Invocation of these CPUs' RCU callbacks will be - offloaded to "rcuox/N" kthreads created for that - purpose, where "x" is "p" for RCU-preempt, and - "s" for RCU-sched, and "N" is the CPU number. - This reduces OS jitter on the offloaded CPUs, - which can be useful for HPC and real-time - workloads. It can also improve energy efficiency - for asymmetric multiprocessors. + rcu_nocbs[=cpu-list] + [KNL] The optional argument is a cpu list, + as described above. + + In kernels built with CONFIG_RCU_NOCB_CPU=y, + enable the no-callback CPU mode, which prevents + such CPUs' callbacks from being invoked in + softirq context. Invocation of such CPUs' RCU + callbacks will instead be offloaded to "rcuox/N" + kthreads created for that purpose, where "x" is + "p" for RCU-preempt, "s" for RCU-sched, and "g" + for the kthreads that mediate grace periods; and + "N" is the CPU number. This reduces OS jitter on + the offloaded CPUs, which can be useful for HPC + and real-time workloads. It can also improve + energy efficiency for asymmetric multiprocessors. + + If a cpulist is passed as an argument, the specified + list of CPUs is set to no-callback mode from boot. + + Otherwise, if the '=' sign and the cpulist + arguments are omitted, no CPU will be set to + no-callback mode from boot but the mode may be + toggled at runtime via cpusets. rcu_nocb_poll [KNL] Rather than requiring that offloaded CPUs @@ -4489,10 +4522,6 @@ on rcutree.qhimark at boot time and to zero to disable more aggressive help enlistment. - rcutree.rcu_idle_gp_delay= [KNL] - Set wakeup interval for idle CPUs that have - RCU callbacks (RCU_FAST_NO_HZ=y). - rcutree.rcu_kick_kthreads= [KNL] Cause the grace-period kthread to get an extra wake_up() if it sleeps three times longer than @@ -4603,8 +4632,12 @@ in seconds. rcutorture.fwd_progress= [KNL] - Enable RCU grace-period forward-progress testing + Specifies the number of kthreads to be used + for RCU grace-period forward-progress testing for the types of RCU supporting this notion. + Defaults to 1 kthread, values less than zero or + greater than the number of CPUs cause the number + of CPUs to be used. rcutorture.fwd_progress_div= [KNL] Specify the fraction of a CPU-stall-warning @@ -4805,6 +4838,29 @@ period to instead use normal non-expedited grace-period processing. + rcupdate.rcu_task_collapse_lim= [KNL] + Set the maximum number of callbacks present + at the beginning of a grace period that allows + the RCU Tasks flavors to collapse back to using + a single callback queue. This switching only + occurs when rcupdate.rcu_task_enqueue_lim is + set to the default value of -1. + + rcupdate.rcu_task_contend_lim= [KNL] + Set the minimum number of callback-queuing-time + lock-contention events per jiffy required to + cause the RCU Tasks flavors to switch to per-CPU + callback queuing. This switching only occurs + when rcupdate.rcu_task_enqueue_lim is set to + the default value of -1. + + rcupdate.rcu_task_enqueue_lim= [KNL] + Set the number of callback queues to use for the + RCU Tasks family of RCU flavors. The default + of -1 allows this to be automatically (and + dynamically) adjusted. This parameter is intended + for use in testing. + rcupdate.rcu_task_ipi_delay= [KNL] Set time in jiffies during which RCU tasks will avoid sending IPIs, starting with the beginning diff --git a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst index 5e51ee5b0358..e4a5fc26f1a9 100644 --- a/Documentation/admin-guide/kernel-per-CPU-kthreads.rst +++ b/Documentation/admin-guide/kernel-per-CPU-kthreads.rst @@ -208,7 +208,7 @@ Do at least one of the following: 2. Enable RCU to do its processing remotely via dyntick-idle by doing all of the following: - a. Build with CONFIG_NO_HZ=y and CONFIG_RCU_FAST_NO_HZ=y. + a. Build with CONFIG_NO_HZ=y. b. Ensure that the CPU goes idle frequently, allowing other CPUs to detect that it has passed through an RCU quiescent state. If the kernel is built with CONFIG_NO_HZ_FULL=y, diff --git a/Documentation/admin-guide/media/platform-cardlist.rst b/Documentation/admin-guide/media/platform-cardlist.rst index 261e7772eb3e..ac73c4166d1e 100644 --- a/Documentation/admin-guide/media/platform-cardlist.rst +++ b/Documentation/admin-guide/media/platform-cardlist.rst @@ -60,6 +60,7 @@ s5p-mfc Samsung S5P MFC Video Codec sh_veu SuperH VEU mem2mem video processing sh_vou SuperH VOU video output stm32-dcmi STM32 Digital Camera Memory Interface (DCMI) +stm32-dma2d STM32 Chrom-Art Accelerator Unit sun4i-csi Allwinner A10 CMOS Sensor Interface Support sun6i-csi Allwinner V3s Camera Sensor Interface sun8i-di Allwinner Deinterlace diff --git a/Documentation/admin-guide/perf/hisi-pcie-pmu.rst b/Documentation/admin-guide/perf/hisi-pcie-pmu.rst new file mode 100644 index 000000000000..294ebbdb22af --- /dev/null +++ b/Documentation/admin-guide/perf/hisi-pcie-pmu.rst @@ -0,0 +1,106 @@ +================================================ +HiSilicon PCIe Performance Monitoring Unit (PMU) +================================================ + +On Hip09, HiSilicon PCIe Performance Monitoring Unit (PMU) could monitor +bandwidth, latency, bus utilization and buffer occupancy data of PCIe. + +Each PCIe Core has a PMU to monitor multi Root Ports of this PCIe Core and +all Endpoints downstream these Root Ports. + + +HiSilicon PCIe PMU driver +========================= + +The PCIe PMU driver registers a perf PMU with the name of its sicl-id and PCIe +Core id.:: + + /sys/bus/event_source/hisi_pcie<sicl>_<core> + +PMU driver provides description of available events and filter options in sysfs, +see /sys/bus/event_source/devices/hisi_pcie<sicl>_<core>. + +The "format" directory describes all formats of the config (events) and config1 +(filter options) fields of the perf_event_attr structure. The "events" directory +describes all documented events shown in perf list. + +The "identifier" sysfs file allows users to identify the version of the +PMU hardware device. + +The "bus" sysfs file allows users to get the bus number of Root Ports +monitored by PMU. + +Example usage of perf:: + + $# perf list + hisi_pcie0_0/rx_mwr_latency/ [kernel PMU event] + hisi_pcie0_0/rx_mwr_cnt/ [kernel PMU event] + ------------------------------------------ + + $# perf stat -e hisi_pcie0_0/rx_mwr_latency/ + $# perf stat -e hisi_pcie0_0/rx_mwr_cnt/ + $# perf stat -g -e hisi_pcie0_0/rx_mwr_latency/ -e hisi_pcie0_0/rx_mwr_cnt/ + +The current driver does not support sampling. So "perf record" is unsupported. +Also attach to a task is unsupported for PCIe PMU. + +Filter options +-------------- + +1. Target filter +PMU could only monitor the performance of traffic downstream target Root Ports +or downstream target Endpoint. PCIe PMU driver support "port" and "bdf" +interfaces for users, and these two interfaces aren't supported at the same +time. + +-port +"port" filter can be used in all PCIe PMU events, target Root Port can be +selected by configuring the 16-bits-bitmap "port". Multi ports can be selected +for AP-layer-events, and only one port can be selected for TL/DL-layer-events. + +For example, if target Root Port is 0000:00:00.0 (x8 lanes), bit0 of bitmap +should be set, port=0x1; if target Root Port is 0000:00:04.0 (x4 lanes), +bit8 is set, port=0x100; if these two Root Ports are both monitored, port=0x101. + +Example usage of perf:: + + $# perf stat -e hisi_pcie0_0/rx_mwr_latency,port=0x1/ sleep 5 + +-bdf + +"bdf" filter can only be used in bandwidth events, target Endpoint is selected +by configuring BDF to "bdf". Counter only counts the bandwidth of message +requested by target Endpoint. + +For example, "bdf=0x3900" means BDF of target Endpoint is 0000:39:00.0. + +Example usage of perf:: + + $# perf stat -e hisi_pcie0_0/rx_mrd_flux,bdf=0x3900/ sleep 5 + +2. Trigger filter +Event statistics start when the first time TLP length is greater/smaller +than trigger condition. You can set the trigger condition by writing "trig_len", +and set the trigger mode by writing "trig_mode". This filter can only be used +in bandwidth events. + +For example, "trig_len=4" means trigger condition is 2^4 DW, "trig_mode=0" +means statistics start when TLP length > trigger condition, "trig_mode=1" +means start when TLP length < condition. + +Example usage of perf:: + + $# perf stat -e hisi_pcie0_0/rx_mrd_flux,trig_len=0x4,trig_mode=1/ sleep 5 + +3. Threshold filter +Counter counts when TLP length within the specified range. You can set the +threshold by writing "thr_len", and set the threshold mode by writing +"thr_mode". This filter can only be used in bandwidth events. + +For example, "thr_len=4" means threshold is 2^4 DW, "thr_mode=0" means +counter counts when TLP length >= threshold, and "thr_mode=1" means counts +when TLP length < threshold. + +Example usage of perf:: + + $# perf stat -e hisi_pcie0_0/rx_mrd_flux,thr_len=0x4,thr_mode=1/ sleep 5 diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst new file mode 100644 index 000000000000..2f066df4ee9c --- /dev/null +++ b/Documentation/admin-guide/pm/amd-pstate.rst @@ -0,0 +1,382 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +=============================================== +``amd-pstate`` CPU Performance Scaling Driver +=============================================== + +:Copyright: |copy| 2021 Advanced Micro Devices, Inc. + +:Author: Huang Rui <ray.huang@amd.com> + + +Introduction +=================== + +``amd-pstate`` is the AMD CPU performance scaling driver that introduces a +new CPU frequency control mechanism on modern AMD APU and CPU series in +Linux kernel. The new mechanism is based on Collaborative Processor +Performance Control (CPPC) which provides finer grain frequency management +than legacy ACPI hardware P-States. Current AMD CPU/APU platforms are using +the ACPI P-states driver to manage CPU frequency and clocks with switching +only in 3 P-states. CPPC replaces the ACPI P-states controls, allows a +flexible, low-latency interface for the Linux kernel to directly +communicate the performance hints to hardware. + +``amd-pstate`` leverages the Linux kernel governors such as ``schedutil``, +``ondemand``, etc. to manage the performance hints which are provided by +CPPC hardware functionality that internally follows the hardware +specification (for details refer to AMD64 Architecture Programmer's Manual +Volume 2: System Programming [1]_). Currently ``amd-pstate`` supports basic +frequency control function according to kernel governors on some of the +Zen2 and Zen3 processors, and we will implement more AMD specific functions +in future after we verify them on the hardware and SBIOS. + + +AMD CPPC Overview +======================= + +Collaborative Processor Performance Control (CPPC) interface enumerates a +continuous, abstract, and unit-less performance value in a scale that is +not tied to a specific performance state / frequency. This is an ACPI +standard [2]_ which software can specify application performance goals and +hints as a relative target to the infrastructure limits. AMD processors +provides the low latency register model (MSR) instead of AML code +interpreter for performance adjustments. ``amd-pstate`` will initialize a +``struct cpufreq_driver`` instance ``amd_pstate_driver`` with the callbacks +to manage each performance update behavior. :: + + Highest Perf ------>+-----------------------+ +-----------------------+ + | | | | + | | | | + | | Max Perf ---->| | + | | | | + | | | | + Nominal Perf ------>+-----------------------+ +-----------------------+ + | | | | + | | | | + | | | | + | | | | + | | | | + | | | | + | | Desired Perf ---->| | + | | | | + | | | | + | | | | + | | | | + | | | | + | | | | + | | | | + | | | | + | | | | + Lowest non- | | | | + linear perf ------>+-----------------------+ +-----------------------+ + | | | | + | | Lowest perf ---->| | + | | | | + Lowest perf ------>+-----------------------+ +-----------------------+ + | | | | + | | | | + | | | | + 0 ------>+-----------------------+ +-----------------------+ + + AMD P-States Performance Scale + + +.. _perf_cap: + +AMD CPPC Performance Capability +-------------------------------- + +Highest Performance (RO) +......................... + +It is the absolute maximum performance an individual processor may reach, +assuming ideal conditions. This performance level may not be sustainable +for long durations and may only be achievable if other platform components +are in a specific state; for example, it may require other processors be in +an idle state. This would be equivalent to the highest frequencies +supported by the processor. + +Nominal (Guaranteed) Performance (RO) +...................................... + +It is the maximum sustained performance level of the processor, assuming +ideal operating conditions. In absence of an external constraint (power, +thermal, etc.) this is the performance level the processor is expected to +be able to maintain continuously. All cores/processors are expected to be +able to sustain their nominal performance state simultaneously. + +Lowest non-linear Performance (RO) +................................... + +It is the lowest performance level at which nonlinear power savings are +achieved, for example, due to the combined effects of voltage and frequency +scaling. Above this threshold, lower performance levels should be generally +more energy efficient than higher performance levels. This register +effectively conveys the most efficient performance level to ``amd-pstate``. + +Lowest Performance (RO) +........................ + +It is the absolute lowest performance level of the processor. Selecting a +performance level lower than the lowest nonlinear performance level may +cause an efficiency penalty but should reduce the instantaneous power +consumption of the processor. + +AMD CPPC Performance Control +------------------------------ + +``amd-pstate`` passes performance goals through these registers. The +register drives the behavior of the desired performance target. + +Minimum requested performance (RW) +................................... + +``amd-pstate`` specifies the minimum allowed performance level. + +Maximum requested performance (RW) +................................... + +``amd-pstate`` specifies a limit the maximum performance that is expected +to be supplied by the hardware. + +Desired performance target (RW) +................................... + +``amd-pstate`` specifies a desired target in the CPPC performance scale as +a relative number. This can be expressed as percentage of nominal +performance (infrastructure max). Below the nominal sustained performance +level, desired performance expresses the average performance level of the +processor subject to hardware. Above the nominal performance level, +processor must provide at least nominal performance requested and go higher +if current operating conditions allow. + +Energy Performance Preference (EPP) (RW) +......................................... + +Provides a hint to the hardware if software wants to bias toward performance +(0x0) or energy efficiency (0xff). + + +Key Governors Support +======================= + +``amd-pstate`` can be used with all the (generic) scaling governors listed +by the ``scaling_available_governors`` policy attribute in ``sysfs``. Then, +it is responsible for the configuration of policy objects corresponding to +CPUs and provides the ``CPUFreq`` core (and the scaling governors attached +to the policy objects) with accurate information on the maximum and minimum +operating frequencies supported by the hardware. Users can check the +``scaling_cur_freq`` information comes from the ``CPUFreq`` core. + +``amd-pstate`` mainly supports ``schedutil`` and ``ondemand`` for dynamic +frequency control. It is to fine tune the processor configuration on +``amd-pstate`` to the ``schedutil`` with CPU CFS scheduler. ``amd-pstate`` +registers adjust_perf callback to implement the CPPC similar performance +update behavior. It is initialized by ``sugov_start`` and then populate the +CPU's update_util_data pointer to assign ``sugov_update_single_perf`` as +the utilization update callback function in CPU scheduler. CPU scheduler +will call ``cpufreq_update_util`` and assign the target performance +according to the ``struct sugov_cpu`` that utilization update belongs to. +Then ``amd-pstate`` updates the desired performance according to the CPU +scheduler assigned. + + +Processor Support +======================= + +The ``amd-pstate`` initialization will fail if the _CPC in ACPI SBIOS is +not existed at the detected processor, and it uses ``acpi_cpc_valid`` to +check the _CPC existence. All Zen based processors support legacy ACPI +hardware P-States function, so while the ``amd-pstate`` fails to be +initialized, the kernel will fall back to initialize ``acpi-cpufreq`` +driver. + +There are two types of hardware implementations for ``amd-pstate``: one is +`Full MSR Support <perf_cap_>`_ and another is `Shared Memory Support +<perf_cap_>`_. It can use :c:macro:`X86_FEATURE_CPPC` feature flag (for +details refer to Processor Programming Reference (PPR) for AMD Family +19h Model 51h, Revision A1 Processors [3]_) to indicate the different +types. ``amd-pstate`` is to register different ``static_call`` instances +for different hardware implementations. + +Currently, some of Zen2 and Zen3 processors support ``amd-pstate``. In the +future, it will be supported on more and more AMD processors. + +Full MSR Support +----------------- + +Some new Zen3 processors such as Cezanne provide the MSR registers directly +while the :c:macro:`X86_FEATURE_CPPC` CPU feature flag is set. +``amd-pstate`` can handle the MSR register to implement the fast switch +function in ``CPUFreq`` that can shrink latency of frequency control on the +interrupt context. The functions with ``pstate_xxx`` prefix represent the +operations of MSR registers. + +Shared Memory Support +---------------------- + +If :c:macro:`X86_FEATURE_CPPC` CPU feature flag is not set, that means the +processor supports shared memory solution. In this case, ``amd-pstate`` +uses the ``cppc_acpi`` helper methods to implement the callback functions +that defined on ``static_call``. The functions with ``cppc_xxx`` prefix +represent the operations of acpi cppc helpers for shared memory solution. + + +AMD P-States and ACPI hardware P-States always can be supported in one +processor. But AMD P-States has the higher priority and if it is enabled +with :c:macro:`MSR_AMD_CPPC_ENABLE` or ``cppc_set_enable``, it will respond +to the request from AMD P-States. + + +User Space Interface in ``sysfs`` +================================== + +``amd-pstate`` exposes several global attributes (files) in ``sysfs`` to +control its functionality at the system level. They located in the +``/sys/devices/system/cpu/cpufreq/policyX/`` directory and affect all CPUs. :: + + root@hr-test1:/home/ray# ls /sys/devices/system/cpu/cpufreq/policy0/*amd* + /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_highest_perf + /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_lowest_nonlinear_freq + /sys/devices/system/cpu/cpufreq/policy0/amd_pstate_max_freq + + +``amd_pstate_highest_perf / amd_pstate_max_freq`` + +Maximum CPPC performance and CPU frequency that the driver is allowed to +set in percent of the maximum supported CPPC performance level (the highest +performance supported in `AMD CPPC Performance Capability <perf_cap_>`_). +In some of ASICs, the highest CPPC performance is not the one in the _CPC +table, so we need to expose it to sysfs. If boost is not active but +supported, this maximum frequency will be larger than the one in +``cpuinfo``. +This attribute is read-only. + +``amd_pstate_lowest_nonlinear_freq`` + +The lowest non-linear CPPC CPU frequency that the driver is allowed to set +in percent of the maximum supported CPPC performance level (Please see the +lowest non-linear performance in `AMD CPPC Performance Capability +<perf_cap_>`_). +This attribute is read-only. + +For other performance and frequency values, we can read them back from +``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`. + + +``amd-pstate`` vs ``acpi-cpufreq`` +====================================== + +On majority of AMD platforms supported by ``acpi-cpufreq``, the ACPI tables +provided by the platform firmware used for CPU performance scaling, but +only provides 3 P-states on AMD processors. +However, on modern AMD APU and CPU series, it provides the collaborative +processor performance control according to ACPI protocol and customize this +for AMD platforms. That is fine-grain and continuous frequency range +instead of the legacy hardware P-states. ``amd-pstate`` is the kernel +module which supports the new AMD P-States mechanism on most of future AMD +platforms. The AMD P-States mechanism will be the more performance and energy +efficiency frequency management method on AMD processors. + +Kernel Module Options for ``amd-pstate`` +========================================= + +``shared_mem`` +Use a module param (shared_mem) to enable related processors manually with +**amd_pstate.shared_mem=1**. +Due to the performance issue on the processors with `Shared Memory Support +<perf_cap_>`_, so we disable it for the moment and will enable this by default +once we address performance issue on this solution. + +The way to check whether current processor is `Full MSR Support <perf_cap_>`_ +or `Shared Memory Support <perf_cap_>`_ : :: + + ray@hr-test1:~$ lscpu | grep cppc + Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms invpcid cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local clzero irperf xsaveerptr rdpru wbnoinvd cppc arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip pku ospke vaes vpclmulqdq rdpid overflow_recov succor smca fsrm + +If CPU Flags have cppc, then this processor supports `Full MSR Support +<perf_cap_>`_. Otherwise it supports `Shared Memory Support <perf_cap_>`_. + + +``cpupower`` tool support for ``amd-pstate`` +=============================================== + +``amd-pstate`` is supported on ``cpupower`` tool that can be used to dump the frequency +information. And it is in progress to support more and more operations for new +``amd-pstate`` module with this tool. :: + + root@hr-test1:/home/ray# cpupower frequency-info + analyzing CPU 0: + driver: amd-pstate + CPUs which run at the same hardware frequency: 0 + CPUs which need to have their frequency coordinated by software: 0 + maximum transition latency: 131 us + hardware limits: 400 MHz - 4.68 GHz + available cpufreq governors: ondemand conservative powersave userspace performance schedutil + current policy: frequency should be within 400 MHz and 4.68 GHz. + The governor "schedutil" may decide which speed to use + within this range. + current CPU frequency: Unable to call hardware + current CPU frequency: 4.02 GHz (asserted by call to kernel) + boost state support: + Supported: yes + Active: yes + AMD PSTATE Highest Performance: 166. Maximum Frequency: 4.68 GHz. + AMD PSTATE Nominal Performance: 117. Nominal Frequency: 3.30 GHz. + AMD PSTATE Lowest Non-linear Performance: 39. Lowest Non-linear Frequency: 1.10 GHz. + AMD PSTATE Lowest Performance: 15. Lowest Frequency: 400 MHz. + + +Diagnostics and Tuning +======================= + +Trace Events +-------------- + +There are two static trace events that can be used for ``amd-pstate`` +diagnostics. One of them is the cpu_frequency trace event generally used +by ``CPUFreq``, and the other one is the ``amd_pstate_perf`` trace event +specific to ``amd-pstate``. The following sequence of shell commands can +be used to enable them and see their output (if the kernel is generally +configured to support event tracing). :: + + root@hr-test1:/home/ray# cd /sys/kernel/tracing/ + root@hr-test1:/sys/kernel/tracing# echo 1 > events/amd_cpu/enable + root@hr-test1:/sys/kernel/tracing# cat trace + # tracer: nop + # + # entries-in-buffer/entries-written: 47827/42233061 #P:2 + # + # _-----=> irqs-off + # / _----=> need-resched + # | / _---=> hardirq/softirq + # || / _--=> preempt-depth + # ||| / delay + # TASK-PID CPU# |||| TIMESTAMP FUNCTION + # | | | |||| | | + <idle>-0 [015] dN... 4995.979886: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=15 changed=false fast_switch=true + <idle>-0 [007] d.h.. 4995.979893: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=7 changed=false fast_switch=true + cat-2161 [000] d.... 4995.980841: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=0 changed=false fast_switch=true + sshd-2125 [004] d.s.. 4995.980968: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=4 changed=false fast_switch=true + <idle>-0 [007] d.s.. 4995.980968: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=7 changed=false fast_switch=true + <idle>-0 [003] d.s.. 4995.980971: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=3 changed=false fast_switch=true + <idle>-0 [011] d.s.. 4995.980996: amd_pstate_perf: amd_min_perf=85 amd_des_perf=85 amd_max_perf=166 cpu_id=11 changed=false fast_switch=true + +The cpu_frequency trace event will be triggered either by the ``schedutil`` scaling +governor (for the policies it is attached to), or by the ``CPUFreq`` core (for the +policies with other scaling governors). + + +Reference +=========== + +.. [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming, + https://www.amd.com/system/files/TechDocs/24593.pdf + +.. [2] Advanced Configuration and Power Interface Specification, + https://uefi.org/sites/default/files/resources/ACPI_Spec_6_4_Jan22.pdf + +.. [3] Processor Programming Reference (PPR) for AMD Family 19h Model 51h, Revision A1 Processors + https://www.amd.com/system/files/TechDocs/56569-A1-PUB.zip diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst index f40994c422dc..5d2757e2de65 100644 --- a/Documentation/admin-guide/pm/working-state.rst +++ b/Documentation/admin-guide/pm/working-state.rst @@ -11,6 +11,7 @@ Working-State Power Management intel_idle cpufreq intel_pstate + amd-pstate cpufreq_drivers intel_epb intel-speed-select diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 0e486f41185e..d359bcfadd39 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -905,6 +905,17 @@ enabled, otherwise writing to this file will return ``-EBUSY``. The default value is 8. +perf_user_access (arm64 only) +================================= + +Controls user space access for reading perf event counters. When set to 1, +user space can read performance monitor counter registers directly. + +The default value is 0 (access disabled). + +See Documentation/arm64/perf.rst for more information. + + pid_max ======= |