Tickless

[PartisanEntity]

Been reading about current efforts to make Linux better at saving power. As far as I have read kernel 2.6.21 is now tickless, which means instead checking for tasks between 100 and 1000 times/second it will only be woken up when a task needs to be done.

This will add to power saving at around 15 - 25%.

Also, Intel has released PowerTop, an application that checks how many 'pings' are sent to the processor.

Here is a list of known software:
http://www.linuxpowertop.org/known.php

[reacocard]

Been reading about current efforts to make Linux better at saving power. As far as I have read kernel 2.6.21 is now tickless, which means instead checking for tasks between 100 and 1000 times/second it will only be woken up when a task needs to be done.

This will add to power saving at around 15 - 25%.

Also, Intel has released PowerTop, an application that checks how many 'pings' are sent to the processor.

Here is a list of known software:
http://www.linuxpowertop.org/known.php

This tickless thing sounds really good. A 20% increase on my 6 hours of battery life would be an insane 7+ hours! And that's with wifi on! Doesn't gutsy already have .21? Can any gutsy users confirm a battery life increase?

[prizrak]

This tickless thing sounds really good. A 20% increase on my 6 hours of battery life would be an insane 7+ hours! And that's with wifi on! Doesn't gutsy already have .21? Can any gutsy users confirm a battery life increase?

I doubt there would be much increase with Gutsy being a beta and all.

I am tempted to try out the testing builds because battery life is the absolute killer on my laptop. With two batteries (primary and secondary) I can only get 4 hours. This is of course wi-fi + Beryl and an nVidia card.

[5-HT]

Doesn't gutsy already have .21? Gutsy has a patched 2.6.22rc

Can any gutsy users confirm a battery life increase?
I've been running a custom 2.6.21-ck2 kernel with tickless support for a while now. Haven't really noticed any significant increase in battery life, but I don't really keep my notebook on for long periods of time when idling. Perhaps by tracking down costly wakeups with PowerTop I'd really be able to take advantage of a dynamic/tickless kernel.
cheers,

[Mahesh_Roy]

I ran the x86 based tickless patches and i wish to do the same for my PPC board as well. Are there any patches for PPC32? Can i get these patches anywhere?"

[khensucat]

From what I've read, it takes more than the tickless kernel to give you real-life power savings. In a head to head at Phoronix, Dapper actually gave better battery life than Gutsy because of less overhead and bling, running processes, etc... ;) A tickless kernel underneath Compiz, tracker, etc.. does you almost no good at all.

ETA: That was at release time, though, so that info could be outdated by now.

[Presto123]

I'm getting about an hour or more extra on my lappy battery with Gutsy than Vista. But, I would guess that's no surprise.

[erykroom]

My battery lasts with Gutsy about 4 hours. In Windows XP it was 7,5 hours.
Ok when I got the laptop and XP was on it the battery was new, but iI doubt that the lifetime of a battery can degrade so fast. (7 months)

[ssam]

My battery lasts with Gutsy about 4 hours. In Windows XP it was 7,5 hours.
Ok when I got the laptop and XP was on it the battery was new, but iI doubt that the lifetime of a battery can degrade so fast. (7 months)

maybe a specific piece of hardware that linux does not know how to put in to a low energy mode. what graphics card and wirless do you have? what CPU? are you running compiz and tracker?

[erykroom]

I think the hardware should be ok because it's mostly from Intel Corporation and Intel has pretty good driver support. But ofcourse I'm no expert on hardware compability.
My computer
arko@erykroom:~$ lspci -tv
-[0000:00]-+-00.0 Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub
+-02.0 Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller
+-02.1 Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller
+-1b.0 Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller
+-1c.0-[0000:0b]--
+-1c.1-[0000:0c]----00.0 Intel Corporation PRO/Wireless 3945ABG Network Connection
+-1c.3-[0000:0d-0e]--
+-1d.0 Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1
+-1d.1 Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2
+-1d.2 Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3
+-1d.3 Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4
+-1d.7 Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller
+-1e.0-[0000:02]--+-00.0 Broadcom Corporation BCM4401-B0 100Base-TX
| +-01.0 Ricoh Co Ltd R5C832 IEEE 1394 Controller
| +-01.1 Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter
| +-01.2 Ricoh Co Ltd R5C843 MMC Host Controller
| +-01.3 Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter
| \-01.4 Ricoh Co Ltd xD-Picture Card Controller
+-1f.0 Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge
+-1f.2 Intel Corporation 82801GBM/GHM (ICH7 Family) SATA IDE Controller
\-1f.3 Intel Corporation 82801G (ICH7 Family) SMBus Controller