Power Management works for your Gentoo system?

eccerr0r

I guess this is another one of these polls.

Power management seems very powerful [groan] these days, curious how far people configured their machines, if it works. I've recently run into many machines that ACPI power management actually works, and some that still fail miserably. Curious as to how far people got their machines configured, if they care about it at all.

Notes:
The S0 C1-C4 option probably works OK for servers, the machine will still save power.

The S0 C5-C7 states are probably only good for tablets, phones, and possibly laptops but just adding that for fun. These are the "machine must always be 'on' yet still on battery power"

This is only for CPU/GPU power down. Ignore hard drive spin down. Also, ignore the fact if you bought low power hardware, this is just a software poll (Gentoo) whether or not power savings work, and besides the C-states can reduce power consumption even more!)

I didn't include S1/S2 as these seem fairly rare. I had a machine that only could S1 but not S3, but oh well. Pick whatever option.
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ct85711 · Veteran Joined: 27 Sep 2005 Posts: 1791

For desktops, most times I don't even enable acpi to begin with; as I keep my machine running 24/7. The only times I ever shut down those machines is if I go on vacation or I am installing new hardware.

When I had a laptop, I did get acpi fully working on it, but still only used shutdown even then. The acpi was mostly used so I can reduce my processor's speed to the lowest possible; to prevent the machine overheating. Running boinc on my laptop for a couple months, keeping a 100% cpu usage didn't turn out too well for that machine.

Dr.Willy · Guru Joined: 15 Jul 2007 Posts: 547 Location: NRW, Germany

Have Gentoo on my laptop which S2Rs and Hibernates peacefully.

Yamakuzure · Posted: Tue Jan 13, 2015 2:00 pm Post subject:

My laptop sleeps by pressing Fn+F1 (or closing lid when on battery) in 1-3 seconds, wakes up in the same time.

I do not use suspend to disk, as this, although it works, takes ages with 32GB RAM.
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Levns · n00b Joined: 02 Dec 2014 Posts: 7

Suspend to ram works no problem, and a voluntarily disabled suspend to disk.

Having a SSD my system is already very fast to boot, so I don't really see the point of suspend to disk.

eccerr0r · Posted: Tue Jan 13, 2015 3:18 pm Post subject:

I got power management working on all computers that support it, but the machines I use most I still tend to just shutdown completely and restart completely. Most of these machines are SSD and most of them are systemd so boot times are negligible so shutdown/boot and application restart are fast. Memory leaks are flushed out by reboots whereas suspend/resume does not :D The laptops get suspend/resume mostly for battery conservation. Desktops too, in case I need to move them. I suppose in the past many desktops do not suspend correctly for me and have a chance for crashing on resume which results in something no different than doing unclean shutdowns. That was a chance I didn't want to take in the past, but many machines are now quite reliable.

On the other hand my server machines I don't configure suspend/resume as they were meant to be on all the time, and thus boot times don't matter. Well, I was thinking about at least getting hibernation working (in case I need to move machines and have to disconnect power, or perhaps even use it when there's an impending power outage as an option to shutdown) and making sure C-states working to at least save a little power when they're on.

I'm surprised people don't even look at getting C-states working, though it should mostly work out of the box if ACPI is enabled (which is needed for most modern machines to enable SMP). Then again I guess it doesn't matter in this case - if it works, don't care if it works and the system runs fine, then all is good as if it were never enabled ...
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Ant P. · Watchman Joined: 18 Apr 2009 Posts: 6920

Desktop needs S5, doesn't have fully working S3 because the radeon driver sucks, and the CPU has a C1E erratum making it all but useless.
I use udev rules to turn off my mouse/tablet lights after 10 minutes of inactivity. Not a power saver but much less annoying.

Laptop has working S3, C1-C4.
Disk interface stuck in IDE emulation mode (Intel sucks, Asus sucks) so no AHCI power management for me.

LAN router/server has C1+C2, which is as good as it probably gets.

Fitzcarraldo · Posted: Tue Jan 13, 2015 6:33 pm Post subject:

Suspend to RAM and Suspend to Disk both work fine on my Compal NBLB2 laptop. Gentoo ~amd64, kernel 3.17.1-gentoo-r1, OpenRC, eudev, xorg-server 1.14.7, ati-drivers 14.12-r3, KDE 4.14.3.

stephan-t · Tux's lil' helper Joined: 12 May 2014 Posts: 122

I use S3 suspend to RAM and work perfectly.

truekaiser · l33t Joined: 05 Mar 2004 Posts: 801

Hibernate works on my laptop, but suspend to ram doesn't. It wakes up right after suspending.
The desktop has completely working s1-5.

energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2048 Location: Germany

avx · Advocate Joined: 21 Jun 2004 Posts: 2152

Suspend to RAM works clean on my ThinkPad. I'd be interested in trying s2disk, didn't yet as I don't know if it would "easily" work given my setup(one efi-partition, one luks->lvm->other partitions).

On a sidenote, I'm not sure why, but poweroff->poweron is actually faster than just rebooting. Meaning that for some reason, if I power on the machine it takes about 3seconds before showing me the luks prompt, while after a reboot it takes a few seconds longer to go from bootlogo to passing to the kernel.
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Roman_Gruber · Posted: Thu Jan 22, 2015 4:12 pm Post subject:

MAy I ask which kernel and userspace you guys use to get it working? I used to use tuxonice a few years ago.

I want to ask for openrc / nvidia-closed-drivers / gentoo-sources.

Anyway it is kinda in the opposite of my hole box as it is encrypted with luks.

eccerr0r · Posted: Thu Jan 22, 2015 8:09 pm Post subject:

I'm just using the stock kernel (gentoo-sources is good enough). Been working OK for a while now.

But yes, resume from RAM (S3) and even resume from hibernate (S4) tend to be faster than a full boot. However a clean shutdown and restarting from a clean slate for just a few more seconds (unlike minutes for a HDD boot) versus the chance the machine won't resume properly is good extra insurance against corruption.
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cryptosteve · Veteran Joined: 04 Jan 2004 Posts: 1169 Location: GER

I only use suspend to ram and that works great. I have no hibernation here.

I need to use networkmanager to get a network connection after waking up from s2r.
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eccerr0r · Posted: Mon Jan 26, 2015 7:17 am Post subject:

One thing I did notice during the times I used Linux in-kernel suspend to disk: they actually support compressed hibernation images. This speeds up hibernate drastically, as well as tend to shrink the swap space required to hibernate. I'm running a 1GB swapfile for hibernating one of my 2GB machines, as long as I'm not storing uncompressable files in RAM it will tend to write out a lot less than 1GB to hibernate.

Then again sometimes I do have to do tricks like dropping the caches before suspending...
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The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

I think the poll is missing an option. Don't care about power management because boot times are laughable.

I went with the 24/7 option since it is the closest. I might be cynical, but most of the time it seems like the suspend and hibernate options are only useful on a windows machine where the boot time is actually significant. Otherwise, it is a solution waiting for a problem.
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Goverp · Advocate Joined: 07 Mar 2007 Posts: 2006

FWIW, my laptop suspends and hibernates without problem, and I use stock gentoo-sources, not tuxonice. I use hibernate 'cos time from power-on to KDE desktop is minutes, whereas resume from hibernate is about 30 sec.

My desktop machine does neither suspend nor hibernate, cos it's about 30 seconds from power-on to KDE desktop. This allows me to disable the suspend/hibernate options in the kernel, which may save bits of code inserted all over the place.
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eccerr0r · Posted: Mon Jan 26, 2015 2:56 pm Post subject:

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

True, modern hardware is really the only reason fast boot up works well.

Although, 15 seconds vs about a minute on the same hardware for windows 8 in a practically pristine state says there is still a huge performance differential between the two OSs.
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EmaRsk · Apprentice Joined: 07 Sep 2004 Posts: 158 Location: Italy

I'm on a laptop. I never used hibernation. Suspend to RAM works fine and I use it sometimes, but as The Doctor said, shutdown and boot times are so short that I mostly just use them.