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9485e4ca0b
linux/drivers/cpufreq
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Rafael J. Wysocki 9485e4ca0b cpufreq: governor: Fix handling of special cases in dbs_update() 
As reported in KBZ 69821:

"With CONFIG_HZ_PERIODIC=y cpu stays at the lowest frequcency 800MHz
 even if usage goes to 100%, frequency does not scale up, the governor
 in use is ondemand. Neither works conservative. Performance and
 userspace governors work as expected.

 With CONFIG_NO_HZ_IDLE or CONFIG_NO_HZ_FULL cpu scales up with ondemand
 as expected."

Analysis carried out by Chen Yu leads to the conclusion that the
observed issue is due to idle_time in dbs_update() representing a
negative number in which case the function will return 0 as the load
(unless load is greater than 0 for another CPU sharing the policy),
although that need not be the right choice.

Indeed, idle_time representing a negative number means that during
the last sampling interval the CPU was almost 100% busy on the rough
average, so 100 should be returned as the load in that case.

Modify the code accordingly and rearrange it to clarify the handling
of all of the special cases in it.  While at it, also avoid returning
zero as the load if time_elapsed is 0 (it doesn't really make sense
to return 0 then).

Link: https://bugzilla.kernel.org/show_bug.cgi?id=69821
Tested-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: Timo Valtoaho <timo.valtoaho@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-05-06 14:24:23 +02:00
..
acpi-cpufreq.c cpufreq: ACPI: Remove freq_table from acpi_cpufreq_data 2016-04-09 01:54:31 +02:00
amd_freq_sensitivity.c cpufreq: governor: Make governor private data per-policy 2016-03-09 14:41:08 +01:00
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
cppc_cpufreq.c cpufreq: ACPI / CPPC: Add module support for cppc_cpufreq driver 2016-04-25 15:59:35 +02:00
cpufreq_conservative.c cpufreq: governor: New data type for management part of dbs_data 2016-04-02 01:09:00 +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 cpufreq: governor: Fix handling of special cases in dbs_update() 2016-05-06 14:24:23 +02:00
cpufreq_governor.h cpufreq: governor: Change confusing struct field and variable names 2016-04-28 15:10:08 +02:00
cpufreq_ondemand.c cpufreq: governor: New data type for management part of dbs_data 2016-04-02 01:09:00 +02:00
cpufreq_ondemand.h cpufreq: governor: Relocate definitions of tuners structures 2016-03-09 14:41:09 +01:00
cpufreq_performance.c cpufreq: Clean up default and fallback governor setup 2016-02-05 02:37:42 +01:00
cpufreq_powersave.c cpufreq: Clean up default and fallback governor setup 2016-02-05 02:37:42 +01:00
cpufreq_stats.c cpufreq: stats: drop unnecessary locking 2015-01-23 23:06:45 +01:00
cpufreq_userspace.c cpufreq: Fix GOV_LIMITS handling for the userspace governor 2016-05-05 01:30:38 +02:00
cpufreq-dt-platdev.c cpufreq: tango: Use generic platdev driver 2016-05-05 01:36:57 +02:00
cpufreq-dt.c cpufreq: dt: Kill platform-data 2016-04-28 15:22:43 +02:00
cpufreq-nforce2.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
cpufreq.c Merge back cpufreq changes for v4.7. 2016-04-25 15:44:01 +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 cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
dbx500-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
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: Prefix exported opp routines with dev_pm_opp_ 2015-09-15 02:03:16 +02:00
freq_table.c cpufreq: Allow drivers to enable boost support after registering driver 2015-08-07 03:25:23 +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: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
imx6q-cpufreq.c Merge branch 'pm-opp' 2015-11-02 00:54:37 +01:00
integrator-cpufreq.c cpufreq: integrator: Fix module autoload for OF platform driver 2015-09-25 23:29:35 +02:00
intel_pstate.c cpufreq: intel_pstate: Ignore _PPC processing under HWP 2016-05-05 01:43:47 +02:00
Kconfig cpufreq: dt: Add generic platform-device creation support 2016-04-09 01:18:42 +02:00
Kconfig.arm cpufreq: hisilicon: Use generic platdev driver 2016-04-25 16:18:24 +02:00
Kconfig.powerpc cpufreq: qoriq: rename the driver 2015-03-18 22:35:16 +01:00
Kconfig.x86 cpufreq: intel_pstate: Enforce _PPC limits 2016-04-28 01:01:39 +02:00
kirkwood-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
longhaul.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
longhaul.h
longrun.c cpufreq: add new routine cpufreq_verify_within_cpu_limits() 2013-10-16 00:50:23 +02:00
loongson2_cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
ls1x-cpufreq.c MIPS: Loongson: Naming style cleanup and rework 2015-06-21 21:53:59 +02:00
Makefile cpufreq: mvebu: Move cpufreq code into drivers/cpufreq/ 2016-04-28 15:22:43 +02:00
maple-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
mt8173-cpufreq.c cpufreq: mt8173: use list_for_each_entry*() 2016-04-09 01:27:54 +02:00
mvebu-cpufreq.c cpufreq: mvebu: Move cpufreq code into drivers/cpufreq/ 2016-04-28 15:22:43 +02:00
omap-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
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 cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency 2015-12-10 00:17:03 +01:00
pmac32-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
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 ACPI / processor: Drop an unused argument of a cleanup routine 2015-07-22 22:11:16 +02:00
powernow-k8.h cpufreq: powernow-k8: Suppress checkpatch warnings 2014-05-17 01:27:01 +02:00
powernv-cpufreq.c cpufreq: powernv: Ramp-down global pstate slower than local-pstate 2016-04-27 23:56:58 +02:00
ppc_cbe_cpufreq_pervasive.c
ppc_cbe_cpufreq_pmi.c cpufreq: ppc_cbe_cpufreq_pmi: make the driver explicitly non-modular 2016-04-09 01:11:04 +02:00
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: Fix cooling device registration issue during suspend 2016-04-25 16:07:02 +02:00
s3c24xx-cpufreq-debugfs.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
s3c24xx-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
s3c64xx-cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
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: s3c: remove incorrect __init annotations 2015-02-19 06:36:53 +01:00
s3c2440-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
s5pv210-cpufreq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
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 cpufreq: sa1110: set memory type for h3600 2014-07-16 14:30:17 +02:00
sc520_freq.c cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
scpi-cpufreq.c cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table 2016-05-05 01:40:04 +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: Convert existing drivers to use cpufreq_freq_transition_{begin|end} 2014-03-26 16:41:41 +01:00
sparc-us2e-cpufreq.c cpufreq: add 'freq_table' in struct cpufreq_policy 2014-03-12 01:06:00 +01:00
sparc-us3-cpufreq.c cpufreq: add 'freq_table' in struct cpufreq_policy 2014-03-12 01:06:00 +01:00
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 cpufreq: Use consistent prefixing via pr_fmt 2016-04-09 01:35:18 +02:00
sti-cpufreq.c cpufreq: st: Provide runtime initialised driver for ST's platforms 2015-12-12 02:55:21 +01:00
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
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