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Mobile Users Beware: Linux Has Major Power Regression

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  • #51
    Originally posted by Michael View Post
    On a clean install you won't ever see that prompt unless your boot fails. Add a new line of 'set timeout=5' to /boot/grub/grub.cfg as the easiest quick way to get the menu back.

    Okay, another Sandy Bridge system... I've seen reports earlier of the power issue under SNB too.
    Thx.

    on an interesting note, I was seeing 29W idle / 109-110W load with the B2 board but I don't remember what kernel it was.

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    • #52
      BTW, those users who have the power problem under Ubuntu, click the 'This bug affects me' on https://bugs.launchpad.net/ubuntu/+s...ux/+bug/760131
      Michael Larabel
      http://www.michaellarabel.com/

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      • #53
        Pentium-M, Debian. It's been a while my machine seems to be running hotter. I'm 100% sure about it, but I don't have any figures for the temperature sensor is hardwired to 2 states: 75 C (which means 'fine') and 85 C (which means 'bad'). I know. Anyway, I found out that some updates to laptop-mode and cpufreq-utils overwrote their config files and the CPU was set to 'ondemand' rather than 'conservative'. In any case, that wasn't the culprit. The fan still kicks in way more often than before. Before I installed 2.6.38? I can't tell, but I guess so from the article. Too bad I must've forgotten to enable detailed power statistics on my last compile, for I don't get the wakeups count in PowerTop.

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        • #54
          If all this is true this is a serious problem!! But even more serious would be the fact that quality tests done by linux foundation didn't see that regression during the release cycle (WTF ).

          Increasing 10-20% power consumption on stable kernels on all linux machines around the world is a painful problem that should be avoided.

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          • #55
            anyways, I looked in the grub menu; only have 2.6.38-x's in it


            wonder if there's a 2.6.37.6 .deb that can be used on 11.04

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            • #56
              Originally posted by Michael View Post
              BTW, those users who have the power problem under Ubuntu, click the 'This bug affects me' on https://bugs.launchpad.net/ubuntu/+s...ux/+bug/760131
              If you look at the powertop output in that bug report, most of the interrupts are from the WIFI card, Chromium, and mouse / keyboard input.

              https://launchpadlibrarian.net/69300044/hardcopy.0

              Of course it's registering over 500 wakeups per second, it isn't idle.

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              • #57
                Power problem does NOT appear to affect me.

                My setup:

                Software: Ubuntu 11.04 Beta 2 fresh install, updated as of 2011-04-25, using Nouveau and Unity in compositing mode.

                Hardware: Compaq Presario V3010AU laptop (AMD Turion X2 1.6GHz, nVidia GeForce 6100 IGP, nVidia chipset, 2Gb DDR2-800, 100Gb 2.5" Seagate HD, purchased in 2006).

                I haven't done battery tests yet, will do in the coming days, but under normal usage, CPU fan does not sound unusual compared to Ubuntu 10.10. Wakeups seem to be the same as Ubuntu 10.10.

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                • #58
                  I've installed the 2.6.38 kernel available from Debian repositories and I don't see anything out of the blue in PowerTop either. Also, I installed 2.6.37 from snapshot.debian.org and I have to say that the fan still tends to run quite often too. I think I overlooked the influence of the weather: it's already getting warmer where I live, so probably the effectiveness of the cooling system is degraded. In any case, without proper measurements (and an isolated environment) I can't really tell whether there's something going on or not.

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                  • #59
                    Originally posted by yotambien View Post
                    In any case, without proper measurements (and an isolated environment) I can't really tell whether there's something going on or not.
                    That's why it's so dicey to find/report power regressions (or take reported ones seriously).

                    I only noticed because for a couple of months now I have collectd running (.deb available) and can look at load/sensors/other system info versus time.

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                    • #60
                      Finally a reason to put my trusty old watt-meter through some use again...

                      Code:
                      kernel 2.6.38.4
                      idle: 50W  load: 95W
                      
                      kernel 2.6.37.6
                      idle: 45W  load: 87W
                      On a i720QM which is running much more quiet now that I've switched back to 2.6.37. So it wasn't the weather after all

                      Great find phoronix/Michael, tnx!

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