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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-12-12 20:45:01 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-12-12 20:45:01 +0100
commitfecc8c0ebd30c41cc66303b6f9476481c5d6d260 (patch)
treeb2e06edcc3425c2a992eb99a8cab1098c4246473 /Documentation
parentMerge branch 'pm-opp' (diff)
parentMerge schedutil governor updates for v4.10. (diff)
downloadlinux-dev-fecc8c0ebd30c41cc66303b6f9476481c5d6d260.tar.xz
linux-dev-fecc8c0ebd30c41cc66303b6f9476481c5d6d260.zip
Merge branch 'pm-cpufreq'
* pm-cpufreq: (51 commits) Documentation: intel_pstate: Document HWP energy/performance hints cpufreq: intel_pstate: Support for energy performance hints with HWP cpufreq: intel_pstate: Add locking around HWP requests cpufreq: ondemand: Set MIN_FREQUENCY_UP_THRESHOLD to 1 cpufreq: intel_pstate: Add Knights Mill CPUID MAINTAINERS: Add bug tracking system location entry for cpufreq cpufreq: dt: Add support for zx296718 cpufreq: acpi-cpufreq: drop rdmsr_on_cpus() usage cpufreq: acpi-cpufreq: Convert to hotplug state machine cpufreq: intel_pstate: fix intel_pstate_exit_perf_limits() prototype cpufreq: intel_pstate: Set EPP/EPB to 0 in performance mode cpufreq: schedutil: Rectify comment in sugov_irq_work() function cpufreq: intel_pstate: increase precision of performance limits cpufreq: intel_pstate: round up min_perf limits cpufreq: Make cpufreq_update_policy() void ACPI / processor: Make acpi_processor_ppc_has_changed() void cpufreq: Avoid using inactive policies cpufreq: intel_pstate: Generic governors support cpufreq: intel_pstate: Request P-states control from SMM if needed cpufreq: dt: Add support for r8a7743 and r8a7745 ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/cpu-freq/cpufreq-stats.txt6
-rw-r--r--Documentation/cpu-freq/intel-pstate.txt54
-rw-r--r--Documentation/devicetree/bindings/cpufreq/brcm,stb-avs-cpu-freq.txt78
-rw-r--r--Documentation/kernel-parameters.txt9
4 files changed, 142 insertions, 5 deletions
diff --git a/Documentation/cpu-freq/cpufreq-stats.txt b/Documentation/cpu-freq/cpufreq-stats.txt
index 8d9773f23550..3c355f6ad834 100644
--- a/Documentation/cpu-freq/cpufreq-stats.txt
+++ b/Documentation/cpu-freq/cpufreq-stats.txt
@@ -44,11 +44,17 @@ the stats driver insertion.
total 0
drwxr-xr-x 2 root root 0 May 14 16:06 .
drwxr-xr-x 3 root root 0 May 14 15:58 ..
+--w------- 1 root root 4096 May 14 16:06 reset
-r--r--r-- 1 root root 4096 May 14 16:06 time_in_state
-r--r--r-- 1 root root 4096 May 14 16:06 total_trans
-r--r--r-- 1 root root 4096 May 14 16:06 trans_table
--------------------------------------------------------------------------------
+- reset
+Write-only attribute that can be used to reset the stat counters. This can be
+useful for evaluating system behaviour under different governors without the
+need for a reboot.
+
- time_in_state
This gives the amount of time spent in each of the frequencies supported by
this CPU. The cat output will have "<frequency> <time>" pair in each line, which
diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt
index e6bd1e6512a5..1953994ef5e6 100644
--- a/Documentation/cpu-freq/intel-pstate.txt
+++ b/Documentation/cpu-freq/intel-pstate.txt
@@ -48,7 +48,7 @@ In addition to the frequency-controlling interfaces provided by the cpufreq
core, the driver provides its own sysfs files to control the P-State selection.
These files have been added to /sys/devices/system/cpu/intel_pstate/.
Any changes made to these files are applicable to all CPUs (even in a
-multi-package system).
+multi-package system, Refer to later section on placing "Per-CPU limits").
max_perf_pct: Limits the maximum P-State that will be requested by
the driver. It states it as a percentage of the available performance. The
@@ -120,13 +120,57 @@ frequency is fictional for Intel Core processors. Even if the scaling
driver selects a single P-State, the actual frequency the processor
will run at is selected by the processor itself.
+Per-CPU limits
+
+The kernel command line option "intel_pstate=per_cpu_perf_limits" forces
+the intel_pstate driver to use per-CPU performance limits. When it is set,
+the sysfs control interface described above is subject to limitations.
+- The following controls are not available for both read and write
+ /sys/devices/system/cpu/intel_pstate/max_perf_pct
+ /sys/devices/system/cpu/intel_pstate/min_perf_pct
+- The following controls can be used to set performance limits, as far as the
+architecture of the processor permits:
+ /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
+ /sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq
+ /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
+- User can still observe turbo percent and number of P-States from
+ /sys/devices/system/cpu/intel_pstate/turbo_pct
+ /sys/devices/system/cpu/intel_pstate/num_pstates
+- User can read write system wide turbo status
+ /sys/devices/system/cpu/no_turbo
+
+Support of energy performance hints
+It is possible to provide hints to the HWP algorithms in the processor
+to be more performance centric to more energy centric. When the driver
+is using HWP, two additional cpufreq sysfs attributes are presented for
+each logical CPU.
+These attributes are:
+ - energy_performance_available_preferences
+ - energy_performance_preference
+
+To get list of supported hints:
+$ cat energy_performance_available_preferences
+ default performance balance_performance balance_power power
+
+The current preference can be read or changed via cpufreq sysfs
+attribute "energy_performance_preference". Reading from this attribute
+will display current effective setting. User can write any of the valid
+preference string to this attribute. User can always restore to power-on
+default by writing "default".
+
+Since threads can migrate to different CPUs, this is possible that the
+new CPU may have different energy performance preference than the previous
+one. To avoid such issues, either threads can be pinned to specific CPUs
+or set the same energy performance preference value to all CPUs.
+
Tuning Intel P-State driver
-When HWP mode is not used, debugfs files have also been added to allow the
-tuning of the internal governor algorithm. These files are located at
-/sys/kernel/debug/pstate_snb/. The algorithm uses a PID (Proportional
-Integral Derivative) controller. The PID tunable parameters are:
+When the performance can be tuned using PID (Proportional Integral
+Derivative) controller, debugfs files are provided for adjusting performance.
+They are presented under:
+/sys/kernel/debug/pstate_snb/
+The PID tunable parameters are:
deadband
d_gain_pct
i_gain_pct
diff --git a/Documentation/devicetree/bindings/cpufreq/brcm,stb-avs-cpu-freq.txt b/Documentation/devicetree/bindings/cpufreq/brcm,stb-avs-cpu-freq.txt
new file mode 100644
index 000000000000..af2385795d78
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/brcm,stb-avs-cpu-freq.txt
@@ -0,0 +1,78 @@
+Broadcom AVS mail box and interrupt register bindings
+=====================================================
+
+A total of three DT nodes are required. One node (brcm,avs-cpu-data-mem)
+references the mailbox register used to communicate with the AVS CPU[1]. The
+second node (brcm,avs-cpu-l2-intr) is required to trigger an interrupt on
+the AVS CPU. The interrupt tells the AVS CPU that it needs to process a
+command sent to it by a driver. Interrupting the AVS CPU is mandatory for
+commands to be processed.
+
+The interface also requires a reference to the AVS host interrupt controller,
+so a driver can react to interrupts generated by the AVS CPU whenever a command
+has been processed. See [2] for more information on the brcm,l2-intc node.
+
+[1] The AVS CPU is an independent co-processor that runs proprietary
+firmware. On some SoCs, this firmware supports DFS and DVFS in addition to
+Adaptive Voltage Scaling.
+
+[2] Documentation/devicetree/bindings/interrupt-controller/brcm,l2-intc.txt
+
+
+Node brcm,avs-cpu-data-mem
+--------------------------
+
+Required properties:
+- compatible: must include: brcm,avs-cpu-data-mem and
+ should include: one of brcm,bcm7271-avs-cpu-data-mem or
+ brcm,bcm7268-avs-cpu-data-mem
+- reg: Specifies base physical address and size of the registers.
+- interrupts: The interrupt that the AVS CPU will use to interrupt the host
+ when a command completed.
+- interrupt-parent: The interrupt controller the above interrupt is routed
+ through.
+- interrupt-names: The name of the interrupt used to interrupt the host.
+
+Optional properties:
+- None
+
+Node brcm,avs-cpu-l2-intr
+-------------------------
+
+Required properties:
+- compatible: must include: brcm,avs-cpu-l2-intr and
+ should include: one of brcm,bcm7271-avs-cpu-l2-intr or
+ brcm,bcm7268-avs-cpu-l2-intr
+- reg: Specifies base physical address and size of the registers.
+
+Optional properties:
+- None
+
+
+Example
+=======
+
+ avs_host_l2_intc: interrupt-controller@f04d1200 {
+ #interrupt-cells = <1>;
+ compatible = "brcm,l2-intc";
+ interrupt-parent = <&intc>;
+ reg = <0xf04d1200 0x48>;
+ interrupt-controller;
+ interrupts = <0x0 0x19 0x0>;
+ interrupt-names = "avs";
+ };
+
+ avs-cpu-data-mem@f04c4000 {
+ compatible = "brcm,bcm7271-avs-cpu-data-mem",
+ "brcm,avs-cpu-data-mem";
+ reg = <0xf04c4000 0x60>;
+ interrupts = <0x1a>;
+ interrupt-parent = <&avs_host_l2_intc>;
+ interrupt-names = "sw_intr";
+ };
+
+ avs-cpu-l2-intr@f04d1100 {
+ compatible = "brcm,bcm7271-avs-cpu-l2-intr",
+ "brcm,avs-cpu-l2-intr";
+ reg = <0xf04d1100 0x10>;
+ };
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 37babf91f2cb..dfdd38ec149b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1760,6 +1760,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
disable
Do not enable intel_pstate as the default
scaling driver for the supported processors
+ passive
+ Use intel_pstate as a scaling driver, but configure it
+ to work with generic cpufreq governors (instead of
+ enabling its internal governor). This mode cannot be
+ used along with the hardware-managed P-states (HWP)
+ feature.
force
Enable intel_pstate on systems that prohibit it by default
in favor of acpi-cpufreq. Forcing the intel_pstate driver
@@ -1780,6 +1786,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Description Table, specifies preferred power management
profile as "Enterprise Server" or "Performance Server",
then this feature is turned on by default.
+ per_cpu_perf_limits
+ Allow per-logical-CPU P-State performance control limits using
+ cpufreq sysfs interface
intremap= [X86-64, Intel-IOMMU]
on enable Interrupt Remapping (default)