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Firefox will suspend running pages when it is unmapped, so I put it on its own virtual desktop and only switch to that desktop when I need a webpage.

And, if you're like me and have dozens of tabs open for weeks on end, the OneTab extension is pretty awesome too.

I'm using "Auto Tab Discard" and I'm happy with it. It "unloads" the unused tabs and reloads them once you switch back to them.

I'd love to hear more about the tweaks you've done to Arch. I've gone little beyond a few power management things myself (On a Thinkpad X1C Gen 6). I get decent battery life, but I know it could be better. And giving up Arch would be a tough sell to myself.

I have the same laptop as you. Just install the "tlp" package (The Laptop Project). I'm using Debian but the Arch package should have the same name. You can tweak the settings (/etc/default/tlp on Debian) but out of the box that should get you arround ~4W depending on what is running on your laptop. With light usage that gives more than 10 hours of battery life, even if you don't charge the battery to the max to increase its life (see START/STOP_CHARGE_THRESH_BAT0 for Thinkpads in the tlp configuration).

If you have a SSD you can be aggressive on the disk suspend timeout, as there's no spin up/down wear issue as with mechanical disks.

With this the battery life is good enough that I never felt the need to optimize further.

[1] https://linrunner.de/en/tlp/tlp.html

Fantastic. Thanks for the info. I've installed tlp, but I never really looked too deeply into it (yet). Most days at the office I'm plugged in - and that can be a problem too with the battery constantly receiving a charge.

Very little was needed at all, and what I did do is mostly working around firmware bugs.

- Force deep sleep mode, as s2idle doesn't work.

- Set the ASPM policy. To anything. Basically the default doesn't work. (I went with 'powersave', obviously.)

- Run powertop --auto-tune on boot.

- Set the cool-bottom thermal profile, but that's just to make it work as a lap top.

- Run a BIOS upgrade. :V

(fwupdmgr did the whole job for me~)

Awesome, thanks. My BIOS upgrades are such a mess. I get notified that I have them.... but they always fail. I haven't dug into the logs to see why. This is honestly the most lazy I've ever been with a Linux install in 20 years, mostly because everything is working "well enough" that I haven't spent time tweaking it. Better battery life/cooler bottom does sound like something I should strive for though.

I run Fedora on a Thinkpad X1C Gen 3. tlp[1] has been, by far, the best tool in optimising my power usage. powertop for some monitoring, as these days it recommends some less than ideal tunables, especially with regards to SATA power management ("med_power_with_dipm" vs "min_power" [2][3]).

Some modules also have blacklists that prevent certain power saving modes from being enabled. This is true for the snd-hda-intel module to prevent a well known popping sound. Since disabling the blacklist, I haven't encountered the issue however YMMV. Similarly to enable ASPM on the PCIE bus, I've had to force it via a kernel parameter.

With regards to the GPU, I noticed my Intel GPU can scale its frequency between 300mhz and 950mhz but the default minimum was set to 350mhz. Other such tweaks such as enabling frame buffer compression [4], can save you a few more watts.

While the Linux defaults does its best to be suitable across different hardware configurations, you'll have to meddle with many parameters to get it customised to your configuration, and that could bring some instability with it so exercise some caution.

Oh, and also be mindful of the apps you run. The Great Suspender for Chrome can save you some watts, cpu and memory by suspending tabs that are not in use. And switching to a light desktop such as Sway or i3 can also do wonders.

As I type this, my battery is reporting a draw of 3.1 watts, 30% battery remaining with 4:40 of operating time at the current workload.

[1] - https://wiki.archlinux.org/index.php/TLP

[2] - https://hansdegoede.livejournal.com/18412.html

[3] - https://wiki.archlinux.org/index.php/Power_management#SATA_A...

[4] - https://wiki.archlinux.org/index.php/Intel_graphics#Framebuf...

Thanks! Yeah, Just running Slack and Chrome (not to mention Spotify sometimes) can send my resource usage fairly high. I went back to Vim (from a couple of Electron-based editors running in vim-emulation mode). I used i3 a bit for about a year and never quite got it to my liking. Things like bluetooth and audio management seemed kinda hacked together - because they were. i3 isn't an environment, it's just a window manager. That's totally great, but KDE seems so seamless in this area. Worth looking into again though.

The thing with arch is it’s mostly not more tweaks that give you better battery, it’s not having all the crap that Ubuntu preloads running that makes that happen.

Folks think I'm crazy for using Arch as my main dev machine. I'm not an Ubuntu hater at all (it runs my main server in the basement at home)... but it'd be awfully hard to go back to using it as my main machine.

Really? Arch is... boring. Once you've set it up, nothing happens without your permission and you can just keep developing away. Sure you have updates imposed on you, but you can delay them a bit if you dont have time right now, and its not like upgrades are indefinitely avoidable on any other OS.

Using Arch often gives me advance warning that my apps will break on users machines due to changes in libraries. I see the changes first and can add compatibility for the new library version such that it's fixed before affecting my users.

I love it as a daily driver.

Yeah, for me, it's "just right". Most detractors claim it's "bleeding edge". What? just because it's got something newer than Postgres 9.1 available?? (this was my argument against Debian/Ubuntu for a long time)

Totally agree that it's a great daily driver. It has EVERYTHING!

Totally, Arch feels snappier in the same hardware that I am surprised that my machine can hold a lot of power for development.

IIRC Clear Linux's cpufreq governor defaults to performance in contrast to the powersave governor, which most other linux distributions appear to be using. Hence the difference in idle power consumption, i guess.

How did you measure the power usage on Windows?

I'm assuming you used Powertop on Linux.

I used Powertop on Linux, yes.

For Windows, I simply let the laptop run until it had used 50% of the battery. Watts = Joules / second.

On Linux, I used the same methodo to calibrate against powertop. (But found less than 5% of discrepancy anyway.)

The only valid approach is to remove the battery and plug it into a kill-a-watt or similar.

Performance and power saving features are vastly different between battery and AC so I don't feel that is relevant at all.

If we are talking about battery-life at least.

Yes, and that would be accounting for the wrong thing. Battery life can be stretched out with user hostile things like lowering the brightness to two-digit nits and disabling all background tasks, none of which really help gauge the efficiency.

In fact, what mobile device manufacturers have learned is that the best way to save power is to ramp up power to complete a non-IO task in as little time as possible then go back to a lower TDP as that is where peak efficiency (rather than minimal consumption) lies.

Accounting the wrong thing?

I think most people are interested in their battery life when they are measuring their battery life.

Numbers you get while plugged in won't have any relevance to battery life or performance. That even applies to mobile devices, despite their learnings.

Many laptops aren’t stable at full speed without a battery.

I’m not aware of anything other than a MacBook or some micro ultra books that do that because they try to keep the power brick size down. Any device with a user-removable battery should be able to do that, provided you’re using an adapter that provides sufficient current.

That's a good way to estimate but not appropriate for comparing to powertop, due to overhead. Also "50%" of energy is an estimate based on voltage, not actually energy usage. That's why Apple has stopped showing percentages in their OSes.

You should use the same methodology for both.

I thought most laptop batteries use coulomb counting rather than voltage for estimating battery level?

Yes, any decent laptop for sure uses coulomb counting, not a simple voltage measurement.

I'd assume the voltage->percentage function was worked out and the percentage displayed was thus accurate. It would be weird if that wasn't the case.

It us not. I programmed Accu controller. The best way is to track the enery coming in and out. Using only voltage is imprecise bevause the voltage/charge graph look a bit logarihmic, so the more charge you have, the more presision you need to have while measuring charge.This graph as well as total possible energy capacity and ability to Charge depend on Temperature. Also you normally have multiple cells that age differently.

I think it varies with the age of the battery and the operating temperature (probably other things too). Although if they were clever they could probably incorporate those parameters as well..

They use coulomb counting, along with an estimate of how much safely-usable energy is left in the battery.

That estimate is usually accurate, but it can drift a bit over time if you never fully recharge or discharge the battery. Also, when the battery gets old it starts having trouble delivering full current when mostly discharged, which is why you'll sometimes see shutdowns at 5-15% remaining.

You could do further browser optimizations through about:about

The XPS 13 9380 is available with Linux pre-installed, why would you want to mess with that? Or was it a fun/hobby thing?

I feel that going from 8W to 3W, while gaining a more usable system that also sits on ZFS instead of ext4, is more than enough reason.

ext4 doesn't detect corruption. How am I supposed to trust it?

And corruption actually happens.

My Dell has an Sk Hynix NVMe drive that apparently doesn't have safe write on power failure. I know because it somehow woke up in my bag and ran the laptop battery down to 0.

BTRFS was not happy with the state of anything on the drive. I was able to do a rescue copy and verify it with my backups, so after a full restore everything turned out OK.

It seems like a good deal but what about the support and the upgrade path from Dell?

I get what you're saying about the filesystem. Personally, I use par2 for the most important things (photos).

What about it? It doesn't seem to be enormously useful, given I can do so much better on my own.

I got the laptop to have well-supported hardware, not because I was expecting a lot of help from Dell.

Is that all there is to it, just well supported hardware? Dell didn't configure Redhat in any way, to make better use of the hardware? I'm thinking trackpad, sleep and hibernation, graphics etc.?

Ubuntu, not Redhat.

And no, it seems they didn't. They haven't forced deep sleep, for example.

Thanks, very interesting to know about these little shortcomings, and how you solved them.