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<strong>Linux</strong> <strong>Power</strong> <strong>Management</strong><br />
<strong>One</strong> <strong>Step</strong> <strong>Ahead</strong>!<br />
Timo Hoenig <br />
Holger Macht<br />
FOSDEM 2006, February 25th, Brussels<br />
This document is licensed under the GNU Free Documentation License
<strong>Linux</strong> <strong>Power</strong> <strong>Management</strong><br />
<strong>One</strong> <strong>Step</strong> <strong>Ahead</strong>!<br />
➔<br />
<strong>Linux</strong> <strong>Power</strong> <strong>Management</strong><br />
➔<br />
The <strong>Power</strong>save Architecture<br />
➔<br />
Runtime Device <strong>Power</strong> <strong>Management</strong> (RTD-PM)<br />
➔<br />
Live Demo<br />
➔<br />
What's Next<br />
2<br />
© 2006 Novell Inc.
System<br />
Calls<br />
<strong>Linux</strong> <strong>Power</strong> <strong>Management</strong><br />
Clients<br />
<strong>Power</strong>save Daemon<br />
We talk<br />
D-BUS!<br />
CPU Freq<br />
Kernel<br />
ACPI<br />
Device PM<br />
HAL<br />
3
<strong>Power</strong>save Architecture<br />
Clients (K<strong>Power</strong>save, wmpowersave, gkrellm-powersave)<br />
Client implements: Auto-Suspend, Lock Screen, Event Notifications (...)<br />
Daemon interaction: Trigger Suspend, Set CPU frequency, Set Schemes<br />
Battery<br />
Information<br />
<strong>Power</strong>save Libraries<br />
HAL Helper<br />
Functions<br />
D-BUS Helper<br />
Functions<br />
APM<br />
ACPI<br />
RTD-PM<br />
<strong>Power</strong>save Daemon<br />
Suspend<br />
Batteries<br />
CPU<br />
Frequency<br />
Unload<br />
Modules<br />
Scripts<br />
Set Disk<br />
Settings<br />
Handle<br />
Hotkeys<br />
4
Scheme Architecture<br />
CPU Freq.:<br />
dynamic<br />
CPU Freq.:<br />
High<br />
Throttling<br />
50 %<br />
Scheme<br />
»<strong>Power</strong>save«<br />
Scheme<br />
»Performance«<br />
Throttling:<br />
0 %<br />
Throttling<br />
50 %<br />
IDE Disk<br />
Settings<br />
CPU Freq.:<br />
High<br />
Brightness:<br />
Low<br />
CPU Freq.:<br />
dynamic<br />
RTD-PM<br />
Throttling:<br />
0 %<br />
Brightness:<br />
High<br />
Brightness:<br />
Low<br />
Brightness:<br />
High<br />
IDE Disk<br />
Settings<br />
RTD-PM<br />
5<br />
© 2006 Novell Inc.
Validated Distributions<br />
●<br />
SUSE <strong>Linux</strong><br />
●<br />
Fedora Core<br />
●<br />
ALT <strong>Linux</strong><br />
●<br />
Debian<br />
●<br />
Ubuntu<br />
●<br />
Kubuntu<br />
●<br />
Gentoo<br />
6<br />
© 2006 Novell Inc.
Runtime Device <strong>Power</strong> <strong>Management</strong> (RTD-PM)<br />
• Today, we can:<br />
• switch the global system state and CPU frequency<br />
• adjust LCD brightness<br />
• What do we get<br />
• Next:<br />
• Save time (suspend and resume cycle)<br />
• Save power consumption at the expense of performance<br />
• Runtime Device <strong>Power</strong> <strong>Management</strong> (RTD-PM)<br />
• What do we get<br />
• Extend battery lifetime by switching off unnecessary<br />
subsystems or devices (LAN, WLAN, USB, Modem, ...)<br />
7<br />
© 2006 Novell Inc.
Runtime Device <strong>Power</strong> <strong>Management</strong><br />
• <strong>Power</strong> States According to ACPI<br />
• D0 (fully-on, mandatory)<br />
• D1, D2 (depending on device class, optional)<br />
• D3 (off, device context lost, mandatory)<br />
• Switch Device <strong>Power</strong> State<br />
1. Identify (e.g. lspci)<br />
2. echo -n [0-3] > $SYSFS_PATH<br />
$ lspci |grep Ethernet<br />
02:0e.0 Ethernet controller: Broadcom Ethernet<br />
$ echo -n 3 > /sys/bus/pci/devices/0000:02:0e.0/power/state<br />
• We should not require users to use echo<br />
• UI required, enhance <strong>Power</strong>save Daemon clients<br />
8<br />
© 2006 Novell Inc.
Test Environment<br />
Laptop<br />
(no<br />
battery)<br />
Laptop<br />
running QtDMM<br />
[A]<br />
9<br />
© 2006 Novell Inc.
Example: IPW 2100<br />
Set device to power state D3<br />
0.825 A<br />
Device fully powered<br />
Set device to<br />
power state D0<br />
0.773 A<br />
Device in D3<br />
10<br />
© 2006 Novell Inc.
Live Demo<br />
11<br />
© 2006 Novell Inc.
12<br />
What's Next
User Space Software Suspend<br />
Kernel Interface<br />
/dev/snapshot<br />
I/O Controls<br />
- SNAPSHOT_FREEZE<br />
- SNAPSHOT_AVAIL_SWAP<br />
- SNAPSHOT_*<br />
User Space Tools<br />
Suspend<br />
Resume<br />
Compression<br />
Bootsplash<br />
13
Dynticks<br />
• Skip timer ticks if CPU is idle<br />
• Make HZ dynamic<br />
• HZ is arch depending<br />
➔<br />
Allow the CPU to enter C3 more often<br />
• Problems<br />
• Losing interrupts<br />
14<br />
© 2006 Novell Inc.
Running Out of Time^w Battery.<br />
Open Discussion<br />
Thanks for coming!
Resources of Interest<br />
- http://powersave.sourceforge.net/pm-report/<br />
- http://www.opensuse.org/Projects_<strong>Power</strong>save<br />
- http://powersave.sourceforge.net<br />
- http://sourceforge.net/Projects/<strong>Power</strong>save<br />
- Mailing lists:<br />
- powersave-users@forge.novell.com<br />
- powersave-devel@forge.novell.com<br />
16<br />
© 2006 Novell Inc.
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