user/sven/linux.git/include/linux/cpufreq.h, branch v4.14.45

x86 / CPU: Always show current CPU frequency in /proc/cpuinfo

2018-01-10T08:31:20Z

commit 7d5905dc14a87805a59f3c5bf70173aac2bb18f8 upstream. After commit 890da9cf0983 (Revert "x86: do not use cpufreq_quick_get() for /proc/cpuinfo "cpu MHz"") the "cpu MHz" number in /proc/cpuinfo on x86 can be either the nominal CPU frequency (which is constant) or the frequency most recently requested by a scaling governor in cpufreq, depending on the cpufreq configuration. That is somewhat inconsistent and is different from what it was before 4.13, so in order to restore the previous behavior, make it report the current CPU frequency like the scaling_cur_freq sysfs file in cpufreq. To that end, modify the /proc/cpuinfo implementation on x86 to use aperfmperf_snapshot_khz() to snapshot the APERF and MPERF feedback registers, if available, and use their values to compute the CPU frequency to be reported as "cpu MHz". However, do that carefully enough to avoid accumulating delays that lead to unacceptable access times for /proc/cpuinfo on systems with many CPUs. Run aperfmperf_snapshot_khz() once on all CPUs asynchronously at the /proc/cpuinfo open time, add a single delay upfront (if necessary) at that point and simply compute the current frequency while running show_cpuinfo() for each individual CPU. Also, to avoid slowing down /proc/cpuinfo accesses too much, reduce the default delay between consecutive APERF and MPERF reads to 10 ms, which should be sufficient to get large enough numbers for the frequency computation in all cases. Fixes: 890da9cf0983 (Revert "x86: do not use cpufreq_quick_get() for /proc/cpuinfo "cpu MHz"") Signed-off-by: Rafael J. Wysocki Acked-by: Thomas Gleixner Tested-by: Thomas Gleixner Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

Merge branch 'pm-cpufreq-sched'

2017-09-03T22:05:22Z

* pm-cpufreq-sched: cpufreq: schedutil: Always process remote callback with slow switching cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily cpufreq: Return 0 from ->fast_switch() on errors cpufreq: Simplify cpufreq_can_do_remote_dvfs() cpufreq: Process remote callbacks from any CPU if the platform permits sched: cpufreq: Allow remote cpufreq callbacks cpufreq: schedutil: Use unsigned int for iowait boost cpufreq: schedutil: Make iowait boost more energy efficient

cpufreq: Simplify cpufreq_can_do_remote_dvfs()

2017-08-08T15:09:02Z

The if () in cpufreq_can_do_remote_dvfs() is superfluous, so drop it and simply return the value of the expression under it. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Process remote callbacks from any CPU if the platform permits

2017-08-01T12:24:54Z

On many platforms, CPUs can do DVFS across cpufreq policies. i.e CPU from policy-A can change frequency of CPUs belonging to policy-B. This is quite common in case of ARM platforms where we don't configure any per-cpu register. Add a flag to identify such platforms and update cpufreq_can_do_remote_dvfs() to allow remote callbacks if this flag is set. Also enable the flag for cpufreq-dt driver which is used only on ARM platforms currently. Signed-off-by: Viresh Kumar Acked-by: Saravana Kannan Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki

sched: cpufreq: Allow remote cpufreq callbacks

2017-08-01T12:24:53Z

With Android UI and benchmarks the latency of cpufreq response to certain scheduling events can become very critical. Currently, callbacks into cpufreq governors are only made from the scheduler if the target CPU of the event is the same as the current CPU. This means there are certain situations where a target CPU may not run the cpufreq governor for some time. One testcase to show this behavior is where a task starts running on CPU0, then a new task is also spawned on CPU0 by a task on CPU1. If the system is configured such that the new tasks should receive maximum demand initially, this should result in CPU0 increasing frequency immediately. But because of the above mentioned limitation though, this does not occur. This patch updates the scheduler core to call the cpufreq callbacks for remote CPUs as well. The schedutil, ondemand and conservative governors are updated to process cpufreq utilization update hooks called for remote CPUs where the remote CPU is managed by the cpufreq policy of the local CPU. The intel_pstate driver is updated to always reject remote callbacks. This is tested with couple of usecases (Android: hackbench, recentfling, galleryfling, vellamo, Ubuntu: hackbench) on ARM hikey board (64 bit octa-core, single policy). Only galleryfling showed minor improvements, while others didn't had much deviation. The reason being that this patch only targets a corner case, where following are required to be true to improve performance and that doesn't happen too often with these tests: - Task is migrated to another CPU. - The task has high demand, and should take the target CPU to higher OPPs. - And the target CPU doesn't call into the cpufreq governor until the next tick. Based on initial work from Steve Muckle. Signed-off-by: Viresh Kumar Acked-by: Saravana Kannan Acked-by: Peter Zijlstra (Intel) Signed-off-by: Rafael J. Wysocki

cpufreq: Add CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING cpufreq driver flag

2017-07-25T22:15:46Z

The policy->transition_latency field is used for multiple purposes today and its not straight forward at all. This is how it is used: A. Set the correct transition_latency value. B. Set it to CPUFREQ_ETERNAL because: 1. We don't want automatic dynamic switching (with ondemand/conservative) to happen at all. 2. We don't know the transition latency. This patch handles the B.1. case in a more readable way. A new flag for the cpufreq drivers is added to disallow use of cpufreq governors which have dynamic_switching flag set. All the current cpufreq drivers which are setting transition_latency unconditionally to CPUFREQ_ETERNAL are updated to use it. They don't need to set transition_latency anymore. There shouldn't be any functional change after this patch. Signed-off-by: Viresh Kumar Reviewed-by: Dominik Brodowski Signed-off-by: Rafael J. Wysocki

cpufreq: Replace "max_transition_latency" with "dynamic_switching"

2017-07-25T22:15:45Z

There is no limitation in the ondemand or conservative governors which disallow the transition_latency to be greater than 10 ms. The max_transition_latency field is rather used to disallow automatic dynamic frequency switching for platforms which didn't wanted these governors to run. Replace max_transition_latency with a boolean (dynamic_switching) and check for transition_latency == CPUFREQ_ETERNAL along with that. This makes it pretty straight forward to read/understand now. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: Use transition_delay_us for legacy governors as well

2017-07-22T00:25:20Z

The policy->transition_delay_us field is used only by the schedutil governor currently, and this field describes how fast the driver wants the cpufreq governor to change CPUs frequency. It should rather be a common thing across all governors, as it doesn't have any schedutil dependency here. Create a new helper cpufreq_policy_transition_delay_us() to get the transition delay across all governors. Signed-off-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: governor: Drop min_sampling_rate

2017-07-22T00:25:20Z

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 Signed-off-by: Rafael J. Wysocki

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux

2017-07-14T20:12:32Z

Pull thermal management updates from Zhang Rui: - Improve thermal cpu_cooling interaction with cpufreq core. The cpu_cooling driver is designed to use CPU frequency scaling to avoid high thermal states for a platform. But it wasn't glued really well with cpufreq core. For example clipped-cpus is copied from the policy structure and its much better to use the policy->cpus (or related_cpus) fields directly as they may have got updated. Not that things were broken before this series, but they can be optimized a bit more. This series tries to improve interactions between cpufreq core and cpu_cooling driver and does some fixes/cleanups to the cpu_cooling driver. (Viresh Kumar) - A couple of fixes and cleanups in thermal core and imx, hisilicon, bcm_2835, int340x thermal drivers. (Arvind Yadav, Dan Carpenter, Sumeet Pawnikar, Srinivas Pandruvada, Willy WOLFF) * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (24 commits) thermal: bcm2835: fix an error code in probe() thermal: hisilicon: Handle return value of clk_prepare_enable thermal: imx: Handle return value of clk_prepare_enable thermal: int340x: check for sensor when PTYP is missing Thermal/int340x: Fix few typos and kernel-doc style thermal: fix source code documentation for parameters thermal: cpu_cooling: Replace kmalloc with kmalloc_array thermal: cpu_cooling: Rearrange struct cpufreq_cooling_device thermal: cpu_cooling: 'freq' can't be zero in cpufreq_state2power() thermal: cpu_cooling: don't store cpu_dev in cpufreq_cdev thermal: cpu_cooling: get_level() can't fail thermal: cpu_cooling: create structure for idle time stats thermal: cpu_cooling: merge frequency and power tables thermal: cpu_cooling: get rid of 'allowed_cpus' thermal: cpu_cooling: OPPs are registered for all CPUs thermal: cpu_cooling: store cpufreq policy cpufreq: create cpufreq_table_count_valid_entries() thermal: cpu_cooling: use cpufreq_policy to register cooling device thermal: cpu_cooling: get rid of a variable in cpufreq_set_cur_state() thermal: cpu_cooling: remove cpufreq_cooling_get_level() ...