redonkable/alistair23-linux
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Stratos Karafotis dfa5bb6225 cpufreq: ondemand: Change the calculation of target frequency 
The ondemand governor calculates load in terms of frequency and
increases it only if load_freq is greater than up_threshold
multiplied by the current or average frequency.  This appears to
produce oscillations of frequency between min and max because,
for example, a relatively small load can easily saturate minimum
frequency and lead the CPU to the max.  Then, it will decrease
back to the min due to small load_freq.

Change the calculation method of load and target frequency on the
basis of the following two observations:

 - Load computation should not depend on the current or average
   measured frequency.  For example, absolute load of 80% at 100MHz
   is not necessarily equivalent to 8% at 1000MHz in the next
   sampling interval.

 - It should be possible to increase the target frequency to any
   value present in the frequency table proportional to the absolute
   load, rather than to the max only, so that:

   Target frequency = C * load

   where we take C = policy->cpuinfo.max_freq / 100.

Tested on Intel i7-3770 CPU @ 3.40GHz and on Quad core 1500MHz Krait.
Phoronix benchmark of Linux Kernel Compilation 3.1 test shows an
increase ~1.5% in performance. cpufreq_stats (time_in_state) shows
that middle frequencies are used more, with this patch.  Highest
and lowest frequencies were used less by ~9%.

[rjw: We have run multiple other tests on kernels with this
 change applied and in the vast majority of cases it turns out
 that the resulting performance improvement also leads to reduced
 consumption of energy.  The change is additionally justified by
 the overall simplification of the code in question.]

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-26 01:06:43 +02:00
..
accessibility
acpi ACPI video support fixes for 3.11 2013-07-21 10:11:04 -07:00
amba
ata Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
atm
auxdisplay
base Driver core patches for 3.11-rc2 2013-07-18 12:48:40 -07:00
bcma bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
block Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze 2013-07-10 10:16:07 -07:00
bluetooth Bluetooth: Add missing reset_resume dev_pm_ops 2013-06-23 00:23:53 +01:00
bus ARM SoC device tree changes 2013-07-02 14:23:01 -07:00
cdrom drivers/cdrom/cdrom.c: use kzalloc() for failing hardware 2013-07-03 16:07:25 -07:00
char Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
clk Power management and ACPI updates for 3.11-rc1 2013-07-03 14:35:40 -07:00
clocksource clocksource+irqchip: delete __cpuinit usage from all related files 2013-07-14 19:36:57 -04:00
connector
cpufreq cpufreq: ondemand: Change the calculation of target frequency 2013-07-26 01:06:43 +02:00
cpuidle Power management and ACPI updates for 3.11-rc1 2013-07-03 14:35:40 -07:00
crypto crypto: talitos: use sg_pcopy_to_buffer() 2013-07-09 10:33:30 -07:00
dca
devfreq Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
dio
dma drivers/dma/iop-adma.c: fix new warnings 2013-07-09 10:33:19 -07:00
edac Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
eisa
extcon drivers: avoid format string in dev_set_name 2013-07-03 16:07:41 -07:00
firewire
firmware efivars: check for EFI_RUNTIME_SERVICES 2013-07-11 11:00:31 +01:00
fmc FMC: fix error handling in probe() function 2013-06-24 16:23:25 -07:00
gpio Power management and ACPI updates for 3.11-rc1 2013-07-03 14:35:40 -07:00
gpu ACPI video support fixes for 3.11 2013-07-21 10:11:04 -07:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-07-04 15:35:08 -07:00
hsi drivers: avoid format string in dev_set_name 2013-07-03 16:07:41 -07:00
hv drivers: hv: allocate synic structures before hv_synic_init() 2013-06-24 16:24:17 -07:00
hwmon Single patch to staticize a local variable 2013-07-18 11:32:36 -07:00
hwspinlock
i2c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
ide Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide 2013-07-10 18:15:41 -07:00
idle
iio The first round of IIO fixes for the 3.11 cycle. 2013-07-16 22:41:38 -07:00
infiniband Main batch of InfiniBand/RDMA changes for 3.11 merge window: 2013-07-13 12:57:21 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-07-13 18:05:13 -07:00
iommu IOMMU Updates for Linux 3.11 2013-07-10 14:46:40 -07:00
ipack
irqchip clocksource+irqchip: delete __cpuinit usage from all related files 2013-07-14 19:36:57 -04:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
leds leds: mc13783: Fix "uninitialized variable" warning 2013-07-02 08:44:02 -07:00
lguest Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
macintosh macintosh/windfarm: Remove obsolete cleanup for clientdata 2013-07-01 11:46:56 +10:00
mailbox
md md/raid1: fix bio handling problems in process_checks() 2013-07-18 14:18:04 +10:00
media [media] saa7134: Fix unlocked snd_pcm_stop() call 2013-07-15 21:25:14 +02:00
memory
memstick drivers/memstick/host/r592.c: convert to module_pci_driver 2013-07-03 16:08:06 -07:00
message drivers: avoid format strings in names passed to alloc_workqueue() 2013-07-03 16:07:41 -07:00
mfd For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
misc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
mmc MMC highlights for 3.11: 2013-07-10 11:16:00 -07:00
mtd A couple of fixes and clean-ups, allow for assigning user-defined 2013-07-05 12:09:48 -07:00
net macvtap: do not zerocopy if iov needs more pages than MAX_SKB_FRAGS 2013-07-18 13:04:25 -07:00
nfc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
ntb
nubus
of Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
oprofile drivers: delete __cpuinit usage from all remaining drivers files 2013-07-14 19:36:59 -04:00
parisc parisc: fix LMMIO mismatch between PAT length and MASK register 2013-07-09 22:09:16 +02:00
parport Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
pci Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
pcmcia Driver core patches for 3.11-rc1 2013-07-02 11:44:19 -07:00
pinctrl Pin control changes for the v3.11 kernel cycle: 2013-07-03 11:48:03 -07:00
platform x86 platform drivers: fix gpio leak 2013-07-10 15:42:51 -04:00
pnp PNP / ACPI: avoid garbage in resource name 2013-07-18 01:38:59 +02:00
power Nothing exciting this time, just assorted fixes and cleanups. 2013-07-10 11:13:00 -07:00
pps pps-gpio: add device-tree binding and support 2013-07-03 16:08:06 -07:00
ps3
ptp build some drivers only when compile-testing 2013-06-24 16:41:32 -07:00
pwm pwm: pwm-tiehrpwm: Use clk_enable/disable instead clk_prepare/unprepare. 2013-06-26 23:23:54 +02:00
rapidio Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
regulator For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
remoteproc Trivial remoteproc fixes by Suman Anna, Wei Yongjun and Thomas Meyer. 2013-07-11 12:35:09 -07:00
reset
rpmsg
rtc For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
s390 s390/zcrypt: Alias for new zcrypt device driver base module 2013-07-19 08:37:39 +02:00
sbus
scsi SCSI for-linus on 20130713 2013-07-13 17:41:21 -07:00
sfi
sh Merge branch 'pm-assorted' 2013-06-28 13:01:40 +02:00
sn
spi Merge remote-tracking branch 'spi/fix/xilinx' into spi-linus 2013-07-15 11:46:16 +01:00
ssb Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
staging Staging tree fixes for 3.11-rc2 2013-07-20 15:42:38 -07:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-07-11 12:57:19 -07:00
tc
thermal Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2013-07-11 12:26:08 -07:00
tty Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
uio uio: use vma_pages() to replace (vm_end - vm_start) >> PAGE_SHIFT 2013-07-03 16:07:26 -07:00
usb Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
uwb drivers: avoid format string in dev_set_name 2013-07-03 16:07:41 -07:00
vfio vfio Updates for v3.11 2013-07-10 14:50:08 -07:00
vhost Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-07-11 12:57:19 -07:00
video uvesafb: Really allow mtrr being 0, as documented and warn()ed 2013-07-16 10:24:28 +10:00
virt
virtio No real surprises. 2013-07-10 14:50:58 -07:00
vlynq
vme vme: vme_tsi148.c: fix error return code in tsi148_probe() 2013-06-24 16:23:25 -07:00
w1 drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode 2013-07-03 16:08:06 -07:00
watchdog Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
xen drivers: delete __cpuinit usage from all remaining drivers files 2013-07-14 19:36:59 -04:00
zorro zorro: switch to fixed_size_llseek() 2013-06-29 12:57:28 +04:00
Kconfig For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
Makefile For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00