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1
Power Tuning Linux:
A Case Study
Alexandra Yates
http://01.org/powertop
2
About
Experiment
3
About ExperimentSoftware
• Ubuntu 13.10: Includes Ubuntu Linux Kernel 3.11.0-12.19. Based on
upstream Linux Kernel 3.11.13, upstream Linux Kernel 3.13.7, and
3.14.0.
Hardware
• Microsoft Surface Pro 3• 12-inch 2160 x 1440
• 1.9 GHz Intel Core i5 4300U – Haswell-ULT
• 256 GB SSD Hard Drive
• Battery life: 5 Hours 30 minutes
• Sony VAIO Pro 13
• 1920 x 1080 touch screen LCD
• Intel Inside Core i5 4200U @ 1.60 GHz – Haswell-ULT
• 128 GB SSD drive
• Battery life: 6 Hours 30 minutes http://laptops-and-notebooks.findthebest.com/l/2085/VAIO-Pro-SVP13213CXB
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About Experiment (cont.)HW Tools:
•Yokogawa WT310
•Photometer
SW Tools
•PowerTOP
Other Hardware
•USB drive
•USB mouse
•SD Card
• Tests:
• 10 minutes intervals.
• Wall Power.
• Suspend PM.
• Idle Power Management
(PM).
• Battery fully charged
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The Results
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Out of the Box (OoB) Ubuntu 3.16.0
// change Nits. Number may change according to hardware
$echo 515 > /sys/class/backlight/intel_back/brightness
Savings
54 min
0.00
2.00
4.00
6.00
8.00
10.00
12.00W
att
s
Time (10 minutes)
oob screen on idle oob screen off idle nits screen on idle
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1%0%1%0%2%0%1%0%0%0%0%0%3%
8%
1%
81%
Overall Platform Power Consumption
Audio
NFC
KBC/EC
WLAN/BT
Touch Pannel
Camera
Sensor Hub
SD Card
Thermal Sensor
WWAN
SDD
USB Walkup Ports
LPT
CPU
Memory
Panel
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Linux Kernel 3.16
0
2
4
6
8
10
12
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Linux Kernel 3.16 & PowerTOP
nits_scon_3.16 nits_scoff_3.16 nits_scon_3.16_PWT nits_scoff_3.16_PWT
Time (10 minutes)
Wa
tts
Savings (hh:mm)
SC_ON 1:45
SC_Off 3:00
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Out of the box vs Linux Kernel 3.16 PM Tuned
0
2
4
6
8
10
12
14
16
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Out of the Box vs 3.16 & PowerTOP
oob_scon_idle oob_scoff_idle nits_scon_3.16_PWT nits_scoff_3.16_PWT
Wa
tts
Time (10 minutes)
Savings (hh:mm)
SC_ON 2:24
SC_Off 3:00
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PowerTOP c-states Kernel 3.14.13-2Screen on tunedScreen on
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PowerTOP c-states Kernel 3.16.0Screen on C7 tuned
Linux command line parameters
i915.enable_psr=1
pcie_aspm=force
http://wireless.kernel.org/en/users/
Documentation/ASPM#Enabling_A
SPM_with_setpci
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How is the software behaving?
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PowerTOP Tunables
Tuned Component CommandVM write-back timeout echo '1500' > '/proc/sys/vm/dirty_writeback_centisecs';
Enable SATA link power management for host0 echo 'min_power' > '/sys/class/scsi_host/host0/link_power_management_policy';
NMI watchdog should be turned off echo '0' > '/proc/sys/kernel/nmi_watchdog';
Auto suspend for USB device AX88772 [2-1] echo 'auto' > '/sys/bus/usb/devices/2-1/power/control';
Auto suspend for USB device DT 101 G2 [Kingston] echo 'auto' > '/sys/bus/usb/devices/2-2/power/control';
Auto suspend for USB device eGalaxTouch EXC7910-1031-12.00.03 [eGalax Inc.] echo 'auto' > '/sys/bus/usb/devices/2-3/power/control';
Runtime PM for PCI Device Samsung Electronics Co Ltd Device a800 echo 'auto' > '/sys/bus/pci/devices/0000:03:00.0/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP SMBus Controller echo 'auto' > '/sys/bus/pci/devices/0000:00:1f.3/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP LPC Controller echo 'auto' > '/sys/bus/pci/devices/0000:00:1f.0/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP USB EHCI #1 echo 'auto' > '/sys/bus/pci/devices/0000:00:1d.0/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP PCI Express Root Port 6 echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.4/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP PCI Express Root Port 3 echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.0/power/control';
Runtime PM for PCI Device Intel Corporation Haswell-ULT Integrated Graphics Controller
echo 'auto' > '/sys/bus/pci/devices/0000:00:02.0/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP PCI Express Root Port 4 echo 'auto' > '/sys/bus/pci/devices/0000:00:1c.3/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP HECI #0 echo 'auto' > '/sys/bus/pci/devices/0000:00:16.0/power/control';
Runtime PM for PCI Device Intel Corporation Lynx Point-LP USB xHCI HC echo 'auto' > '/sys/bus/pci/devices/0000:00:14.0/power/control';
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Common Devices
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Background Impact
Time (10 minutes)0
2
4
6
8
10
12
14
16Background Color
oob_debian debian_T black_T white_oob white_T
Wa
tts
OOB OOB 00:04
OOB Tuned 4:35
Tune
d
Tuned 00:31
vsSavings(hh:mm)
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Device Consumption MouseW
att
s
0
2
4
6
8
10
12
14
16
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Device Power Consumption
scon_3.16_pwt mouse_oob mouse_3.16 mouse_3.16_pwt
Time (10 minutes)
Savings (hh:mm)
Tuned 2:25
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Other Distros
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Ubuntu vs DebianW
att
s
0
0.5
1
1.5
2
2.5
3
3.5
4
Ubuntu vs Debian
ubuntu_scon ubuntu_scoff debian_scon debia_scoff
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Conclusion
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Q&APowerTOP is an Open Source Project, Get Involved!!
https://01.org/powertop/get-involved
How to contribute to PowerTOP?
1- Join the mailing list
2- Get the code from the repo
3- Send your patches to the mailing list
