User:Bjordan/Chris Power MGMT

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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

Michael - 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
      • Modify Sugar to collect power usage data
        • Chat with Scott on how to get data on power usage

What other data can activities be providing? Crashes, errors, etc.

Dynamic heuristic gathering / development

  • Activity specific?

Pie menu is nice because it shows all users how much power is being used... without Chris having to yell at developers

Even when off -- embedded controller sits there and waits for power button to be turned on

Why is 708 not waking up on keyboard presses?

  • Lid open -- error, screen on, then back off


Chris has Beamer PDF