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f8475cef90
linux-next/drivers/cpufreq
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Len Brown f8475cef90 x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF 
The goal of this change is to give users a uniform and meaningful
result when they read /sys/...cpufreq/scaling_cur_freq
on modern x86 hardware, as compared to what they get today.

Modern x86 processors include the hardware needed
to accurately calculate frequency over an interval --
APERF, MPERF, and the TSC.

Here we provide an x86 routine to make this calculation
on supported hardware, and use it in preference to any
driver driver-specific cpufreq_driver.get() routine.

MHz is computed like so:

MHz = base_MHz * delta_APERF / delta_MPERF

MHz is the average frequency of the busy processor
over a measurement interval.  The interval is
defined to be the time between successive invocations
of aperfmperf_khz_on_cpu(), which are expected to to
happen on-demand when users read sysfs attribute
cpufreq/scaling_cur_freq.

As with previous methods of calculating MHz,
idle time is excluded.

base_MHz above is from TSC calibration global "cpu_khz".

This x86 native method to calculate MHz returns a meaningful result
no matter if P-states are controlled by hardware or firmware
and/or if the Linux cpufreq sub-system is or is-not installed.

When this routine is invoked more frequently, the measurement
interval becomes shorter.  However, the code limits re-computation
to 10ms intervals so that average frequency remains meaningful.

Discerning users are encouraged to take advantage of
the turbostat(8) utility, which can gracefully handle
concurrent measurement intervals of arbitrary length.

Signed-off-by: Len Brown <len.brown@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-27 01:47:32 +02:00
..
acpi-cpufreq.c cpufreq: Remove CPU hotplug callbacks only if they were initialized 2016-12-21 02:52:52 +01:00
amd_freq_sensitivity.c cpufreq: Reuse new freq-table helpers 2016-07-07 00:14:27 +02:00
arm_big_little_dt.c cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table 2016-05-05 01:40:04 +02:00
arm_big_little.c cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table 2016-05-05 01:40:04 +02:00
arm_big_little.h cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table 2016-05-05 01:40:04 +02:00
at32ap-cpufreq.c cpufreq: at32ap: don't declare local variable as static 2014-04-07 14:31:33 +02:00
blackfin-cpufreq.c blackfin-cpufreq: Mark cpu_set_cclk() as static 2015-12-28 01:51:36 +01:00
bmips-cpufreq.c cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs 2017-02-09 01:22:44 +01:00
brcmstb-avs-cpufreq.c cpufreq: brcmstb-avs-cpufreq: remove unnecessary platform_set_drvdata() 2017-02-09 01:22:46 +01:00
cppc_cpufreq.c cpufreq / CPPC: Add MODULE_DEVICE_TABLE for cppc_cpufreq driver 2016-10-21 15:11:23 +02:00
cpufreq_conservative.c cpufreq: conservative: Allow down_threshold to take values from 1 to 10 2017-06-12 14:28:07 +02:00
cpufreq_governor_attr_set.c cpufreq: governor: Move abstract gov_attr_set code to seperate file 2016-04-02 01:09:01 +02:00
cpufreq_governor.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/cpufreq.h> 2017-03-02 08:42:30 +01:00
cpufreq_governor.h sched/headers: Prepare for new header dependencies before moving code to <linux/sched/cpufreq.h> 2017-03-02 08:42:30 +01:00
cpufreq_ondemand.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/cpufreq.h> 2017-03-02 08:42:30 +01:00
cpufreq_ondemand.h cpufreq: ondemand: Don't keep a copy of freq_table pointer 2016-06-09 00:58:06 +02:00
cpufreq_performance.c cpufreq: governor: Get rid of governor events 2016-06-02 23:24:15 +02:00
cpufreq_powersave.c cpufreq: governor: Get rid of governor events 2016-06-02 23:24:15 +02:00
cpufreq_stats.c Power management updates for v4.11-rc1 2017-02-20 17:41:31 -08:00
cpufreq_userspace.c cpufreq: governor: Get rid of governor events 2016-06-02 23:24:15 +02:00
cpufreq-dt-platdev.c cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platforms 2017-02-09 22:59:00 +01:00
cpufreq-dt.c PM / OPP: Rename dev_pm_opp_get_suspend_opp() and return OPP rate 2017-01-27 11:49:09 +01:00
cpufreq-dt.h cpufreq: dt: Support governor tunables per policy 2016-09-13 02:39:12 +02:00
cpufreq-nforce2.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
cpufreq.c x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF 2017-06-27 01:47:32 +02:00
cris-artpec3-cpufreq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
cris-etraxfs-cpufreq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
davinci-cpufreq.c ARM: davinci: da850: fix da850_set_pll0rate() 2017-01-02 15:02:51 +05:30
dbx500-cpufreq.c cpufreq: dbx500: Manage cooling device from cpufreq driver 2017-03-16 00:14:31 +01:00
e_powersaver.c cpufreq: e_powersaver: Use IS_ENABLED() instead of checking for built-in or module 2016-04-27 22:42:34 +02:00
elanfreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
exynos5440-cpufreq.c PM / OPP: Update OPP users to put reference 2017-01-30 09:22:21 +01:00
freq_table.c cpufreq: Handle sorted frequency tables more efficiently 2016-07-07 00:13:20 +02:00
gx-suspmod.c cpufreq: gx-suspmod: Fix two typos in two comments 2015-06-15 15:46:15 +02:00
highbank-cpufreq.c Merge branch 'mailbox-for-linus' of git://git.linaro.org/landing-teams/working/fujitsu/integration 2014-10-21 11:21:19 -07:00
ia64-acpi-cpufreq.c cpufreq/ia64: Replace racy task affinity logic 2017-04-15 12:20:55 +02:00
imx6q-cpufreq.c cpufreq: imx6q: Fix error handling code 2017-04-19 23:22:01 +02:00
intel_pstate.c cpufreq: intel_pstate: Remove max/min fractions to limit performance 2017-06-24 01:48:12 +02:00
Kconfig cpufreq: qoriq: add ARM64 SoCs support 2017-02-09 14:33:01 +01:00
Kconfig.arm cpufreq: dbx500: add a Kconfig symbol 2017-05-14 13:40:16 +02:00
Kconfig.powerpc cpufreq: qoriq: rename the driver 2015-03-18 22:35:16 +01:00
Kconfig.x86 sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO 2016-11-30 08:27:08 +01:00
kirkwood-cpufreq.c cpufreq: kirkwood-cpufreq:- Handle return value of clk_prepare_enable() 2017-05-30 00:09:41 +02:00
longhaul.c Power management material for v4.7-rc1 2016-05-16 19:17:22 -07:00
longhaul.h
longrun.c cpufreq: add new routine cpufreq_verify_within_cpu_limits() 2013-10-16 00:50:23 +02:00
loongson1-cpufreq.c CPUFREQ: Loongson1: Replace goto out with return in ls1x_cpufreq_probe() 2016-05-13 14:02:08 +02:00
loongson2_cpufreq.c CPUFREQ: Loongson2: drop set_cpus_allowed_ptr() 2017-04-12 13:52:21 +02:00
Makefile cpufreq: dbx500: add a Kconfig symbol 2017-05-14 13:40:16 +02:00
maple-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
mt8173-cpufreq.c cpufreq: mediatek: Add support for MT8176 and MT817x 2017-03-12 23:10:53 +01:00
mvebu-cpufreq.c cpufreq: mvebu: fix integer to pointer cast 2016-06-13 23:49:43 +02:00
omap-cpufreq.c PM / OPP: Update OPP users to put reference 2017-01-30 09:22:21 +01:00
p4-clockmod.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
pasemi-cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
pcc-cpufreq.c Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency" 2016-07-22 23:51:06 +02:00
pmac32-cpufreq.c powerpc updates for 4.7 2016-05-20 10:12:41 -07:00
pmac64-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
powernow-k6.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
powernow-k7.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
powernow-k7.h
powernow-k8.c format-security: move static strings to const 2017-05-08 17:15:14 -07:00
powernow-k8.h cpufreq: powernow-k8: Suppress checkpatch warnings 2014-05-17 01:27:01 +02:00
powernv-cpufreq.c cpufreq: powernv: Add boost files to export ultra-turbo frequencies 2017-02-03 23:59:41 +01:00
ppc_cbe_cpufreq_pervasive.c
ppc_cbe_cpufreq_pmi.c cpufreq: Remove CPUFREQ_START notifier event 2017-02-04 00:05:30 +01:00
ppc_cbe_cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
ppc_cbe_cpufreq.h cpufreq: e_powersaver: Use IS_ENABLED() instead of checking for built-in or module 2016-04-27 22:42:34 +02:00
pxa2xx-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
pxa3xx-cpufreq.c cpufreq: Remove cpufreq_generic_exit() 2014-03-12 01:06:00 +01:00
qoriq-cpufreq.c cpufreq: qoriq: enhance bus frequency calculation 2017-03-12 23:10:53 +01:00
s3c24xx-cpufreq-debugfs.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
s3c24xx-cpufreq.c cpufreq: Return index from cpufreq_frequency_table_target() 2016-06-09 00:58:06 +02:00
s3c64xx-cpufreq.c cpufreq: s3c64xx: remove incorrect __init annotation 2016-12-21 02:54:18 +01:00
s3c2410-cpufreq.c cpufreq: s3c24xx: Remove some dead code 2014-07-19 04:24:59 +09:00
s3c2412-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
s3c2416-cpufreq.c cpufreq: s3c2416: double free on driver init error path 2017-02-09 01:22:45 +01:00
s3c2440-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
s5pv210-cpufreq.c ARM: SoC driver updates for v4.8 2016-08-01 18:36:01 -04:00
sa1100-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
sa1110-cpufreq.c ARM: sa1100: move StrongARM CPU ID checks to cputype.h 2016-08-23 10:25:17 +01:00
sc520_freq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
scpi-cpufreq.c cpufreq-SCPI: Delete unnecessary assignment for the field "owner" 2016-08-18 03:42:32 +02:00
sfi-cpufreq.c cpufreq: sfi: use kmemdup rather than duplicating its implementation 2015-09-01 15:51:15 +02:00
sh-cpufreq.c cpufreq/sh: Replace racy task affinity logic 2017-04-15 12:20:55 +02:00
sparc-us2e-cpufreq.c cpufreq/sparc-us2e: Replace racy task affinity logic 2017-04-15 12:20:56 +02:00
sparc-us3-cpufreq.c cpufreq/sparc-us3: Replace racy task affinity logic 2017-04-15 12:20:55 +02:00
spear-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
speedstep-centrino.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
speedstep-ich.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
speedstep-lib.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
speedstep-lib.h
speedstep-smi.c Annotate hardware config module parameters in drivers/cpufreq/ 2017-04-20 12:02:32 +01:00
sti-cpufreq.c scripts/spelling.txt: add regsiter -> register spelling mistake 2017-05-08 17:15:13 -07:00
tegra20-cpufreq.c cpufreq: tegra20: remove superfluous CONFIG_PM ifdefs 2015-09-26 03:00:57 +02:00
tegra124-cpufreq.c cpufreq: tegra124: No need of setting platform-data 2016-04-09 01:12:09 +02:00
tegra186-cpufreq.c cpufreq: Add Tegra186 cpufreq driver 2017-04-19 23:23:08 +02:00
ti-cpufreq.c cpufreq: make ti-cpufreq explicitly non-modular 2017-02-16 00:58:52 +01:00
unicore2-cpufreq.c cpufreq: unicore32: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO 2014-04-21 23:42:27 +02:00
vexpress-spc-cpufreq.c cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table 2016-05-05 01:40:04 +02:00