#8 Intel powertop: high power usage

[Anonymous]

Playing around with the Inter powertop utility released
just recently, I am finding that the iburst driver is the
worst offender in wakeups-from-idle statistic. It constantly wakes up 250 times a second, even without traffic, reducing battery life.

Example output:
Cn Avg residency (5s) Long term residency avg
C0 (cpu running) ( 2.2%)
C1 0.0ms ( 0.0%) 0.0ms
C2 3.1ms (97.8%) 2.6ms
C3 0.0ms ( 0.0%) 0.0ms

Wakeups-from-idle per second : 319.8
no ACPI power usage estimate available

Top causes for wakeups:
54.3% (250.0) <kernel module> : ib_pcmcia_probe (ib_pcmcia_timer)
27.6% (127.0) firefox-bin : schedule_timeout (process_timeout)
13.2% ( 60.6) <interrupt> : ehci_hcd:usb1, uhci_hcd:usb2, uhci_hcd:usb3,
2.3% ( 10.8) <interrupt> : ide1 DB-ICH4, eth0, radeon@pci:0000:01:00.0
1.1% ( 5.0) dhcdbd : schedule_timeout (process_timeout)
0.4% ( 2.0) python : schedule_timeout (process_timeout)
0.4% ( 2.0) xterm : schedule_timeout (process_timeout)
0.1% ( 0.6) <kernel core> : queue_delayed_work_on (delayed_work_timer_fn
0.1% ( 0.6) hald-addon-stor : do_nanosleep (hrtimer_wakeup)
0.1% ( 0.4) <kernel module> : <e08db200> (irlmp_discovery_timer_expired)
0.1% ( 0.4) NetworkManager : e1000_intr (e1000_watchdog)
0.1% ( 0.4) NetworkManager : schedule_timeout (process_timeout)
0.0% ( 0.2) <kernel core> : neigh_table_init_no_netlink (neigh_periodic_
0.0% ( 0.2) gconfd-2 : schedule_timeout (process_timeout)
0.0% ( 0.2) <kernel core> : page_writeback_init (wb_timer_fn)
0.0% ( 0.2) <kernel core> : end_that_request_last (laptop_timer_fn)
0.0% ( 0.2) init : schedule_timeout (process_timeout)

[Daniel Burr]

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That's just how the driver is written, I'm afraid. It appears to unmask interrupts for memory and IO but then polls the hardware 250 times a second using a timer.

[Nobody/Anonymous]

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This kills power usages. There are API's that can be used instead of polling 250 times a second. With the new tickles Kernel the battery life on my laptop drops 30% when I use the iBurst driver.