• [6.8.3] CPU Isolation Banner


    jsebright
    • Minor

    As soon as I visit Settings > CPU Pinning I get the banner with the title "CPU Isolation: A reboot is required to apply changes"

    The banner persists even though I make no changes. It shows itself when logging into the dashboard on another browser. It clears when the server is rebooted.

    I'm not expecting this banner to show unless I make changes to the "CPU Isolation" section. I should be able to make and apply VM or docker pinning changes without a reboot.

    Don't think diagnostics should be necessary but including them anyway. Note that I've recently made some hardware changes, but spotted this both before and after the change.

    tower-diagnostics-20200421-0955.zip




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    If you changed the isolation in flash settings, it will also show that banner if you go to the CPU Pinning page. I think there's some config in the CPU Pinning page that saves the boot isolcpus and then compared to the current settings and if diff then show banner.

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    46 minutes ago, testdasi said:

    If you changed the isolation in flash settings, it will also show that banner if you go to the CPU Pinning page. I think there's some config in the CPU Pinning page that saves the boot isolcpus and then compared to the current settings and if diff then show banner.

    Correct, there is a check done to see if configured and actual settings (syslinux.cfg) are the same. If not the banner is shown.

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    Thanks both for your posts.

     

    It's odd then. The boot settings show the same "isolcpus" as the CPU pinning page. (as did /boot/syslinux/syslinux.cfg)

    A few days ago I swapped motherboards (& processor), and had gone in to reset the pinnings, saved & rebooted, then got this message.

    I've just rebooted and had the same problem. Looking at the Flash config I see some old & invalid stub settings in the GUI version which I have removed, and have rebooted again. Gone into that page and it's flashed up the banner again.

    What else can I check?

    Edited by jsebright
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    According to your diagnostics, the system has been started with

      isolcpus=2,4,8,10
     

    A check is done if in syslinux.cfg the same setting is present under the "default" section, if not the banner is displayed.

     

    Do you manually change the boot menu selection when starting the system?

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    1 hour ago, bonienl said:

    According to your diagnostics, the system has been started with

      isolcpus=2,4,8,10
     

    A check is done if in syslinux.cfg the same setting is present under the "default" section, if not the banner is displayed.

     

    Do you manually change the boot menu selection when starting the system?

    I run Unraid headless, and use the default (non-gui) option.

    Yes 2,4,8,10 should be isolated.

     

    I've just checked that the IsolCPUs setting matches the flash setting and it does, so have rebooted. 

    Flash settings are OK. I go to settings / CPU pinning and the banner appears as soon as I do that. Isolated CPUs match the flash settings.

    I try removing the all cpu pinning in the settings page, check that they've been removed from the flash settings (they have) and reboot. When I go into the cpu pinning settings I no longer get the banner. Might go back to this.

    I decide to have another go at setting 2,4,8,10. I apply the changes and get the banner. Check the Flash settings and they match up so I reboot again. I go into the dashboard again and don't get the banner - Hooray! I can change docker pinning and still don't get the banner - Hooray!

     

    So, all cleared now, but no idea why that was such a problem. I presume it started when I changed motherboard & cpu (going from 6 cores to 12), and I guess something was failing to check. Could it be the orders were different (2,4,8,10 vs 2,8,4,10 ?) - it certainly appeared to be pinning the correct cores, so it was just the checking that was getting it wrong.

     

    Anyway, the solution for me (and perhaps for anyone else who gets this) was to clear all pinnning, reboot, then re-apply pinning.

     

    Thanks for your help in this.

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    8 minutes ago, jsebright said:

    Could it be the orders were different (2,4,8,10 vs 2,8,4,10 ?)

    That's indeed the issue. The automatic check generates a list in sequence for comparison.

    When you clear and re-appy then the settings themselves will also be in the correct sequence.

    • Thanks 1
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