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Linux Kernel Fastboot [pdf]

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Re: Linux Kernel Fastboot [pdf]

#11
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…

How did you measure the power usage on Windows?

I'm assuming you used Powertop on Linux.

Re: Linux Kernel Fastboot [pdf]

#12

Earlier quoted context omitted.

> 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…

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.)

Re: Linux Kernel Fastboot [pdf]

#13
post #7

Earlier quoted context omitted.

> 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…

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.

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~)

Re: Linux Kernel Fastboot [pdf]

#15

Earlier quoted context omitted.

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.)

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.

Re: Linux Kernel Fastboot [pdf]

#17
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…

I think Sun must've tried and failed. Boot times on late 90's era Solaris/Sparc systems were atrocious compared to Linux/x86 systems of the day.

Re: Linux Kernel Fastboot [pdf]

#18
post #16

> SATA driver init takes 100 to 200 ms even without a real disk That's pretty interesting. Wonder what it is doing?

Probably checking for a real disk? I guess it's got to check all the bus nodes for a disk, even if there's not one.

Re: Linux Kernel Fastboot [pdf]

#19

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'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.
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