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Ubuntu 32-bit, 32-bit PAE, 64-bit Benchmarks

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  • #31
    Can anyone explain the results of the 64-bit Postmark test?

    I think the explanation of the Apache test results is related.

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    • #32
      Originally posted by n0nsense
      There is a new writer at anand, he using Arch for reviews.
      And I totally agree with "'Ubuntu this, Ubuntu that'.
      Michael promised Sabayon review this week.
      Well I must say it was a pleasant surprise, although I'm not much of a
      gamer - it's nice to see linux coverage on major sites like AnandTech.
      Especially considering their quasi-scientific battery usage test with
      xf86-video-ati driver comparing to Windows Catalyst Powerplay goodness.
      On Ubuntu, ofcourse

      Originally posted by energyman
      do it yourself :P
      Why, ofcourse! I'll push some ads too while I'm at it.
      All jokes aside, there is a Gentoo x64 installation pending for me
      I thought I might give it a try and ask Michael to do it for us,
      considering 'vi du vizit Phoronix and vi du not blok ze ads'.

      In my humble opinion there is little sense in doing all that Michael
      does if you can't have comparable results. I know it all gets down to
      out-of-box experience, but AnandTech took the same route with battery
      tests and it didn't bode well for GNU/Linux. At all.

      Cheers!

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      • #33
        Originally posted by linuxjacques View Post
        Can anyone explain the results of the 64-bit Postmark test?

        I think the explanation of the Apache test results is related.
        Apache result is indeed strange... the test uses the prefork mpm with 100 concurrent request so apache spawns about the same number of processes, but it's nowhere near to putting pressure to the VM (plus apache should use zero-copy sendfile for static content).
        My sheevaplug with a tuned apache easily outperforms that CD2 in 32bit mode...
        Another slight problem with this (local) ab test is that basically one core is lost to ab itself.

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        • #34
          Originally posted by clavko View Post
          I know it all gets down to
          out-of-box experience, but AnandTech took the same route with battery
          tests and it didn't bode well for GNU/Linux. At all.

          Cheers!
          LOL, so at anandtech they found out what most of us already know:

          We were left with running the proprietary fglxr 8.600 driver, and while it worked fine in general we had problems with DVD playback. VLC repeatedly crashed during our benchmarks, sometimes after a few minutes, sometimes after 50 minutes. Eventually, we decided to uninstall the proprietary ATI driver and test out the open-source MESA driver. Surprisingly, the open-source driver actually provided a better experience.

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          • #35
            I think there is an error in the article, HIGHMEM_4G enables highmem but not PAE. Only HIGHMEM_64G will enable PAE. HIGHMEM_4G performance hit is measurable in some cases, but only significant if the work dataset is larger than lowmem.

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            • #36
              I've just tested PAE enabled kernel in Kubuntu 9.10 on P4 3GHz (32bit only) with HT and 3GB RAM physical (2,5-2.7GHz logical mapped by BIOS) and I didn't get more logical RAM with PAE - it's the same as without PAE but it looks like running from BIOS to... KDE 4.4b2 (two instances run by two users) takes at least few seconds more with PAE (I haven't measured that precisely).

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              • #37
                BTW, the article says that the system used for testing has 4GB of RAM, was that with memory mapped over the 4GB line or not? If in doubt, look at the beginning of the dmesg for the e820 map, and look for memory mapped above 0x100000000. This is a detail particularly important for DMA to devices.

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                • #38
                  @xeros

                  Your bios has to support remapping too.

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                  • #39
                    Originally posted by Kano View Post
                    @xeros
                    Your bios has to support remapping too.
                    And the chipset too, and unfortunately Intel did not add support to their desktop chipsets until the i955X and i965 series, so the only option is for the BIOS to free more physical address space below the 4GB line. As you have only 3GB of RAM, this should be easy, try changing some BIOS options (maybe relating to the AGP aperture) or updating the BIOS.

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                    • #40
                      So is it a 64 bit kernel on 32 bit userland or a 64 bit kernel with 64 bit userland? That makes a world's difference.

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