summaryrefslogtreecommitdiffstats
path: root/Documentation/admin-guide/pm
AgeCommit message (Collapse)Author
2017-09-04Merge branch 'pm-docs'Rafael J. Wysocki
* pm-docs: PM: docs: Delete the obsolete states.txt document PM: docs: Describe high-level PM strategies and sleep states
2017-09-04Merge branch 'intel_pstate'Rafael J. Wysocki
* intel_pstate: cpufreq: intel_pstate: Shorten a couple of long names cpufreq: intel_pstate: Simplify intel_pstate_adjust_pstate() cpufreq: intel_pstate: Improve IO performance with per-core P-states cpufreq: intel_pstate: Drop INTEL_PSTATE_HWP_SAMPLING_INTERVAL cpufreq: intel_pstate: Drop ->update_util from pstate_funcs cpufreq: intel_pstate: Do not use PID-based P-state selection
2017-09-04Merge branch 'pm-cpufreq'Rafael J. Wysocki
* pm-cpufreq: (33 commits) cpufreq: imx6q: Fix imx6sx low frequency support cpufreq: speedstep-lib: make several arrays static, makes code smaller cpufreq: ti: Fix 'of_node_put' being called twice in error handling path cpufreq: dt-platdev: Drop few entries from whitelist cpufreq: dt-platdev: Automatically create cpufreq device with OPP v2 ARM: ux500: don't select CPUFREQ_DT cpufreq: Convert to using %pOF instead of full_name cpufreq: Cap the default transition delay value to 10 ms cpufreq: dbx500: Delete obsolete driver mfd: db8500-prcmu: Get rid of cpufreq dependency cpufreq: enable the DT cpufreq driver on the Ux500 cpufreq: Loongson2: constify platform_device_id cpufreq: dt: Add r8a7796 support to to use generic cpufreq driver cpufreq: remove setting of policy->cpu in policy->cpus during init cpufreq: mediatek: add support of cpufreq to MT7622 SoC cpufreq: mediatek: add cleanups with the more generic naming cpufreq: rcar: Add support for R8A7795 SoC cpufreq: dt: Add rk3328 compatible to use generic cpufreq driver cpufreq: s5pv210: add missing of_node_put() cpufreq: Allow dynamic switching with CPUFREQ_ETERNAL latency ...
2017-08-29PM: docs: Describe high-level PM strategies and sleep statesRafael J. Wysocki
Reorganize the power management part of admin-guide by adding a description of major power management strategies supported by the kernel (system-wide and working-state power management) to it and dividing the rest of the material into the system-wide PM and working-state PM chapters. On top of that, add a description of system sleep states to the system-wide PM chapter. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
2017-08-21Merge back intel_pstate material for v4.14.Rafael J. Wysocki
2017-07-27cpufreq: docs: Add missing cpuinfo_cur_freq descriptionRafael J. Wysocki
Add a description of the cpuinfo_cur_freq policy attribute in sysfs to the cpufreq documentation under Documentation/admin-guide/pm/ as it is missing after commit 2a0e49279850 (cpufreq: User/admin documentation update and consolidation) that overlooked it. Fixes: 2a0e49279850 (cpufreq: User/admin documentation update and consolidation) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2017-07-26cpufreq: intel_pstate: Do not use PID-based P-state selectionRafael J. Wysocki
All systems with a defined ACPI preferred profile that are not "servers" have been using the load-based P-state selection algorithm in intel_pstate since 4.12-rc1 (mobile systems and laptops have been using it since 4.10-rc1) and no problems with it have been reported to date. In particular, no regressions with respect to the PID-based P-state selection have been reported. Also testing indicates that the P-state selection algorithm based on CPU load is generally on par with the PID-based algorithm performance-wise, and for some workloads it turns out to be better than the other one, while being more straightforward and easier to understand at the same time. Moreover, the PID-based P-state selection algorithm in intel_pstate is known to be unstable in some situation and generally problematic, the issues with it are hard to address and it has become a significant maintenance burden. For these reasons, make intel_pstate use the "powersave" P-state selection algorithm based on CPU load in the active mode on all systems and drop the PID-based P-state selection code along with all things related to it from the driver. Also update the documentation accordingly. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22cpufreq: governor: Drop min_sampling_rateViresh Kumar
The cpufreq core and governors aren't supposed to set a limit on how fast we want to try changing the frequency. This is currently done for the legacy governors with help of min_sampling_rate. At worst, we may end up setting the sampling rate to a value lower than the rate at which frequency can be changed and then one of the CPUs in the policy will be only changing frequency for ever. But that is something for the user to decide and there is no need to have special handling for such cases in the core. Leave it for the user to figure out. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-29cpufreq: Update scaling_cur_freq documentationRafael J. Wysocki
Commit f8475cef9008 "x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF" modified the way the scaling_cur_freq cpufreq policy attribute in sysfs is handled on contemporary Intel-based x86 systems, so update the documentation to reflect that change. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-29cpufreq: intel_pstate: Clean up after performance governor changesRafael J. Wysocki
After commit 82b4e03e01bc (intel_pstate: skip scheduler hook when in "performance" mode) get_target_pstate_use_performance() and get_target_pstate_use_cpu_load() are never called if scaling_governor is "performance", so drop the CPUFREQ_POLICY_PERFORMANCE checks from them as they will never trigger anyway. Moreover, the documentation needs to be updated to reflect the change made by the above commit, so do that too. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
2017-05-14cpufreq: intel_pstate: Document the current behavior and user interfaceRafael J. Wysocki
Add a document describing the current behavior and user space interface of the intel_pstate driver in the RST format and drop the existing outdated intel_pstate.txt document. Also update admin-guide/pm/cpufreq.rst with proper RST references to the new intel_pstate.rst document. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-03-13cpufreq: User/admin documentation update and consolidationRafael J. Wysocki
The user/admin documentation of cpufreq is badly outdated. It conains stale and/or inaccurate information along with things that are not particularly useful. Also, some of the important pieces are missing from it. For this reason, add a new user/admin document for cpufreq containing current information to admin-guide and drop the old outdated .txt documents it is replacing. Since there will be more PM documents in admin-guide going forward, create a separate directory for them and put the cpufreq document in there right away. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>