summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-12 02:03:20 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-12 02:03:20 +0200
commit1fe43114ea7355ec9f336c942aaf3e74d27483a0 (patch)
treea42dfb282f2e3fb3adaa9359494081c67da66293 /Documentation
parentMerge tag 'ktest-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rost... (diff)
parentMerge branches 'pm-cpuidle' and 'pm-qos' (diff)
downloadlinux-1fe43114ea7355ec9f336c942aaf3e74d27483a0.tar.xz
linux-1fe43114ea7355ec9f336c942aaf3e74d27483a0.zip
Merge tag 'pm-4.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management updates from Rafael Wysocki: "These include one big-ticket item which is the rework of the idle loop in order to prevent CPUs from spending too much time in shallow idle states. It reduces idle power on some systems by 10% or more and may improve performance of workloads in which the idle loop overhead matters. This has been in the works for several weeks and it has been tested and reviewed quite thoroughly. Also included are changes that finalize the cpufreq cleanup moving frequency table validation from drivers to the core, a few fixes and cleanups of cpufreq drivers, a cpuidle documentation update and a PM QoS core update to mark the expected switch fall-throughs in it. Specifics: - Rework the idle loop in order to prevent CPUs from spending too much time in shallow idle states by making it stop the scheduler tick before putting the CPU into an idle state only if the idle duration predicted by the idle governor is long enough. That required the code to be reordered to invoke the idle governor before stopping the tick, among other things (Rafael Wysocki, Frederic Weisbecker, Arnd Bergmann). - Add the missing description of the residency sysfs attribute to the cpuidle documentation (Prashanth Prakash). - Finalize the cpufreq cleanup moving frequency table validation from drivers to the core (Viresh Kumar). - Fix a clock leak regression in the armada-37xx cpufreq driver (Gregory Clement). - Fix the initialization of the CPU performance data structures for shared policies in the CPPC cpufreq driver (Shunyong Yang). - Clean up the ti-cpufreq, intel_pstate and CPPC cpufreq drivers a bit (Viresh Kumar, Rafael Wysocki). - Mark the expected switch fall-throughs in the PM QoS core (Gustavo Silva)" * tag 'pm-4.17-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (23 commits) tick-sched: avoid a maybe-uninitialized warning cpufreq: Drop cpufreq_table_validate_and_show() cpufreq: SCMI: Don't validate the frequency table twice cpufreq: CPPC: Initialize shared perf capabilities of CPUs cpufreq: armada-37xx: Fix clock leak cpufreq: CPPC: Don't set transition_latency cpufreq: ti-cpufreq: Use builtin_platform_driver() cpufreq: intel_pstate: Do not include debugfs.h PM / QoS: mark expected switch fall-throughs cpuidle: Add definition of residency to sysfs documentation time: hrtimer: Use timerqueue_iterate_next() to get to the next timer nohz: Avoid duplication of code related to got_idle_tick nohz: Gather tick_sched booleans under a common flag field cpuidle: menu: Avoid selecting shallow states with stopped tick cpuidle: menu: Refine idle state selection for running tick sched: idle: Select idle state before stopping the tick time: hrtimer: Introduce hrtimer_next_event_without() time: tick-sched: Split tick_nohz_stop_sched_tick() cpuidle: Return nohz hint from cpuidle_select() jiffies: Introduce USER_TICK_USEC and redefine TICK_USEC ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/cpu-freq/core.txt12
-rw-r--r--Documentation/cpu-freq/cpu-drivers.txt6
-rw-r--r--Documentation/cpuidle/sysfs.txt6
3 files changed, 13 insertions, 11 deletions
diff --git a/Documentation/cpu-freq/core.txt b/Documentation/cpu-freq/core.txt
index 978463a7c81e..073f128af5a7 100644
--- a/Documentation/cpu-freq/core.txt
+++ b/Documentation/cpu-freq/core.txt
@@ -97,12 +97,10 @@ flags - flags of the cpufreq driver
==================================================================
For details about OPP, see Documentation/power/opp.txt
-dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
- cpufreq_table_validate_and_show() which is provided with the list of
- frequencies that are available for operation. This function provides
- a ready to use conversion routine to translate the OPP layer's internal
- information about the available frequencies into a format readily
- providable to cpufreq.
+dev_pm_opp_init_cpufreq_table -
+ This function provides a ready to use conversion routine to translate
+ the OPP layer's internal information about the available frequencies
+ into a format readily providable to cpufreq.
WARNING: Do not use this function in interrupt context.
@@ -112,7 +110,7 @@ dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
/* Do things */
r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
if (!r)
- cpufreq_table_validate_and_show(policy, freq_table);
+ policy->freq_table = freq_table;
/* Do other things */
}
diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
index 61546ac578d6..6e353d00cdc6 100644
--- a/Documentation/cpu-freq/cpu-drivers.txt
+++ b/Documentation/cpu-freq/cpu-drivers.txt
@@ -259,10 +259,8 @@ CPUFREQ_ENTRY_INVALID. The entries don't need to be in sorted in any
particular order, but if they are cpufreq core will do DVFS a bit
quickly for them as search for best match is faster.
-By calling cpufreq_table_validate_and_show(), the cpuinfo.min_freq and
-cpuinfo.max_freq values are detected, and policy->min and policy->max
-are set to the same values. This is helpful for the per-CPU
-initialization stage.
+The cpufreq table is verified automatically by the core if the policy contains a
+valid pointer in its policy->freq_table field.
cpufreq_frequency_table_verify() assures that at least one valid
frequency is within policy->min and policy->max, and all other criteria
diff --git a/Documentation/cpuidle/sysfs.txt b/Documentation/cpuidle/sysfs.txt
index b6f44f490ed7..d1587f434e7b 100644
--- a/Documentation/cpuidle/sysfs.txt
+++ b/Documentation/cpuidle/sysfs.txt
@@ -40,6 +40,7 @@ total 0
-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
-r--r--r-- 1 root root 4096 Feb 8 10:42 name
-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 residency
-r--r--r-- 1 root root 4096 Feb 8 10:42 time
-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
@@ -50,6 +51,7 @@ total 0
-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
-r--r--r-- 1 root root 4096 Feb 8 10:42 name
-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 residency
-r--r--r-- 1 root root 4096 Feb 8 10:42 time
-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
@@ -60,6 +62,7 @@ total 0
-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
-r--r--r-- 1 root root 4096 Feb 8 10:42 name
-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 residency
-r--r--r-- 1 root root 4096 Feb 8 10:42 time
-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
@@ -70,6 +73,7 @@ total 0
-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
-r--r--r-- 1 root root 4096 Feb 8 10:42 name
-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 residency
-r--r--r-- 1 root root 4096 Feb 8 10:42 time
-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
--------------------------------------------------------------------------------
@@ -78,6 +82,8 @@ total 0
* desc : Small description about the idle state (string)
* disable : Option to disable this idle state (bool) -> see note below
* latency : Latency to exit out of this idle state (in microseconds)
+* residency : Time after which a state becomes more effecient than any
+ shallower state (in microseconds)
* name : Name of the idle state (string)
* power : Power consumed while in this idle state (in milliwatts)
* time : Total time spent in this idle state (in microseconds)