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Linux Kernel Fastboot [pdf]

linuxplumbersconf.org

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Re: Linux Kernel Fastboot [pdf]

#21

Post by rabidrat »

jimmaswell wrote: post #19
lonelappde wrote: post #15

Earlier quoted context omitted.

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'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.

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..

Re: Linux Kernel Fastboot [pdf]

#23

Post by bt848 »

jmccorm wrote: post #4

How nostalgic! Mind you, I say that in a good way! This brings me back to the heydays of Sun Microsystems where they controlled both the hardware (SPARC) and the operating system (Solaris). Sun didn't hesitate to use this to their advantage. With Clear Linux, I see Intel doing some very similar things. Yes, this was just a story about boot time, but it led me to take a look at Clear Linux and it looks like it could b…

Booting a Sun in the 90s took so long that we had the janitor go and power up the CAD lab half an hour before anyone got to the office. Whatever you are nostalgic for wasn’t a Sun.

Re: Linux Kernel Fastboot [pdf]

#25

Post by cocoa19 »

cperciva wrote: post #3

Those of you who are interested in such things might also like to watch my BSDCan 2018 talk: https://www.youtube.com/watch?v=HMywejyXB9k

Sorry for off-topic: I checked your HN profile and tarsnap looks like what I've been searching for a long time. Looks much more straight forward than nextcloud and open source too. Wish you success with your company.

Re: Linux Kernel Fastboot [pdf]

#29

Post by aidenn0 »

Filligree wrote: post #5
jmccorm wrote: post #4

How nostalgic! Mind you, I say that in a good way! This brings me back to the heydays of Sun Microsystems where they controlled both the hardware (SPARC) and the operating system (Solaris). Sun didn't hesitate to use this to their advantage. With Clear Linux, I see Intel doing some very similar things. Yes, this was just a story about boot time, but it led me to take a look at Clear Linux and it looks like it could b…

> Anyone have some experiences with this distro (for better or worse) that they'd like to share? Not much of one, but for a while I was playing with multiple distros trying to find the best possible power management for my laptop. (XPS 13 9380.) Clear did better than the Ubuntu installation that came with it -- but a dead octopus would have done better than that . It was sitting at 6W for non-CPU-intensive work, and…

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.

Re: Linux Kernel Fastboot [pdf]

#30

Post by aidenn0 »

lonelappde wrote: post #15
Filligree wrote: post #12

Earlier quoted context omitted.

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.)

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?
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