User:Bjordan/Chris Power MGMT

Control of power --> transmitter? vs. using repeater

OHM - "Open Hardware Manager" by Richard Hughes

Useful debugging tools for power management:

ohmd --verbose --no-daemon
lsohm # ohm's ideas of what state things are in
lshal # all things hal knows about status of battery, lid, etc
lshal --monitor # realtime, HW events broadcasted to ohm

Wakeup events: (all policy decisions go through ohm)

• Suspend mode - in Joyride
• Sleep mode - in Joyride
  • Wakeup doesn't work well in 703

Idleness detection: (don't want to turn off during an update)

• Mouse/keyboard idle for 60s?
• CPU also idle? # might be doing compile
• Has dbus signal inhibited suspend? or /etc/ohm/inhibit-idle-suspend
• Have tty1 or tty2 been used recently? (printing to or typing to)
• Are audio/camera devices in use? # Not implemented. Record, distance.
• DISTANCE: CHIRP ... idle for 10s ... CHIRP, etc. Not necessarily idle.

In linux: CPU-idle - different states a CPU can be in

Power breakdown: 703

• RAM 700mW DCON 200mW EC 100mW LCD 300mW CPU 1W-3W Backlight
• Maybe make a graph of progress?

Francesca: Mesh/antenna off?

• me: We could collect some data of frequency of checks in order to catch the most mesh networks?

Joe: Hibernation mode?

• Chris: waking up, what hardware will there be?
• Chris: disc space tradeoff makes it hard to hibernate

Next step:

• Better idleness detection
• Faster

Daniel: in wireless, power-saving modes in AP

• If you have AP, large schools have APs
• Chris: OLPC supports that mode
• We may not be doing this, follow up

What needs to be done? How can we help?

• Activities doing a good job vs. bad job of supporting power management
• Look at top - CPU usage
• Look at vmstat (how many context switches are happening?)
• Timer list using powertop wikipedia
  • Needs dynamic ticks ext on kernel
  • /proc/timer_list and /proc/timer_stats
  • Could be thrown into tinderbox
  • Provide powertop in joyride and/or a GUI for powertop
• Pie menu in main screen as memory usage by each activity
  • Also power usage pie
    • Accumulated power register