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Temporary fix regarding FPS fluctuations in openSUSE 11.3 since fglrx 10.10

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  • Temporary fix regarding FPS fluctuations in openSUSE 11.3 since fglrx 10.10

    Gotta investigate this further, but this is what seems to work so far:

    When booting, manually add
    Code:
    noapic pci=nomsi
    to the default GRUB entry.

    2 days in a row that this trick results in flawless performance.

    Why not add it to the GRUB menu once and for all and be done with it, you may ask? Because I remember trying it and that it only worked after the first reboot, never on cold starts.

    So I'm gonna monitor how interrupts are flipped around during the coming week and report on my findings.

  • #2
    That didn't last long...
    New theory:
    When experiencing FPS fluctuations, reboot and change kernel boot options.
    Back in a few days...

    Comment


    • #3
      Originally posted by PsynoKhi0 View Post
      Gotta investigate this further, but this is what seems to work so far:

      When booting, manually add
      Code:
      noapic pci=nomsi
      to the default GRUB entry.

      2 days in a row that this trick results in flawless performance.

      Why not add it to the GRUB menu once and for all and be done with it, you may ask? Because I remember trying it and that it only worked after the first reboot, never on cold starts.

      So I'm gonna monitor how interrupts are flipped around during the coming week and report on my findings.
      Did you also tried it with Catalyst 10.11 / 10.12?

      That might be more likely to be a kernel-like problem (some backported patch or similar) than a driver one, but there also are some motherboard configurations that don't like to have fglrx + MSI enabled...

      Personally, the only kernel-line option I put in grub for loading fglrx with no problems is passing the option "nomodeset", editing the file /boot/grub/menu.lst.

      Cheers and Merry Xmas!

      Comment


      • #4
        `noapic' will very adversely affect your CPU performance if you have a multicore processor. AFAIK, absence of an APIC essentially limits you to a single core. MSI is a very useful performance improvement commonly used for on-board network cards, and they can also help for other PCI/PCI-Express cards.

        Disabling these things shouldn't be necessary; you might want to hand-roll your own kernel and tweak the interrupt frequency and the preemption model.

        Comment


        • #5
          Originally posted by evolution View Post
          Did you also tried it with Catalyst 10.11 / 10.12?
          Yes, using 10.12 right now, but these slowdowns have been plaguing me since 10.10, hence the title.

          Originally posted by evolution View Post
          That might be more likely to be a kernel-like problem (some backported patch or similar) than a driver one,
          Probably, though I had idea where to start from, so I gave those options a shot.

          Originally posted by evolution View Post
          Personally, the only kernel-line option I put in grub for loading fglrx with no problems is passing the option "nomodeset", editing the file /boot/grub/menu.lst.
          Never been a issue here, and I've tried that too

          Originally posted by evolution View Post
          Cheers and Merry Xmas!
          Thanks, you too!

          Comment


          • #6
            Originally posted by allquixotic View Post
            `noapic' will very adversely affect your CPU performance if you have a multicore processor. AFAIK, absence of an APIC essentially limits you to a single core. MSI is a very useful performance improvement commonly used for on-board network cards, and they can also help for other PCI/PCI-Express cards.
            The "noapic" was a desperate move.
            Thanks for the info about MSI, I merely went after recommendationsfound on this forum.

            Originally posted by allquixotic View Post
            Disabling these things shouldn't be necessary; you might want to hand-roll your own kernel and tweak the interrupt frequency and the preemption model.
            I'll look into that, thanks for the heads-up! Sounds like a hassle for a stable release though The openSUSE kernel guys might be interested.

            Comment


            • #7
              Set all your cpu cores to max performance before starting any game.

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