Higher wake-up rate when running on battery

From: Alessandro Guido
Date: Wed May 27 2009 - 05:05:19 EST

I can observe a strange behaviour wrt timer wake-ups when looking at powertop:

- when running on AC, about 8 wake-ups per second.

- when running on battery, the number of wake-ups grows to about 11 and the
main wake-up producers are:
23.1% ( 3.9) <kernel core> : hrtimer_start_range_ns (tick_sched_timer)
19.2% ( 3.2) <interrupt> : acpi

[ These wake-up rates refer to X running KDE4, wi-fi off (by physical switch)
and no usb device connected. ]

Is this a normal behaviour?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/