performance: fix scheduler, fix dell performance

[kajusnau]

Follow-up to #1542, addressing some issues

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Description of Changes

1. Added a patch to fix scheduler settings not being applied at runtime

   • Upstream PR created as well
     Our patch should be removed when a new release of s76-scheduler is available in nixpkgs
   • With this patch, processes should have their niceness and priority values adjusted at runtime properly

2. Scheduler assignment and priority fixes

   • Added fixes to resolve scheduler assignment conflicts
   • Reduced scheduler priority and I/O aggressiveness to reduce instances where single processes may hog system memory and disk.

3. Dell 7330 memory assignment changes

   • Reduced flatpak-vm and gui-vm memory assignments.

4. Removed tuned-gui entry from desktop shortcuts

Type of Change

• New Feature
• Bug Fix
• Improvement / Refactor

Related Issues / Tickets

Checklist

• Clear summary in PR description
• Detailed and meaningful commit message(s)
• Commits are logically organized and squashed if appropriate
• Contribution guidelines followed
• Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• Author has run make-checks and it passes
• All automatic GitHub Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing Instructions

Applicable Targets

• Orin AGX aarch64
• Orin NX aarch64
• Lenovo X1 x86_64
• Dell Latitude x86_64
• System 76 x86_64

Installation Method

• Requires full re-installation
• Can be updated with nixos-rebuild ... switch
• Other:

Test Steps To Verify:

Scheduler tests:

1. Boot into Ghaf and verify tuned-gui desktop entry does not appear in the app library
2. In gui-vm:
   1. Launch an app, e.g. cosmic-term Terminal
   2. Remotely or in the terminal itself, run watch -n 1 "top -p $(pidof cosmic-term)"
   3. Observe the NI (niceness) column value - it should adjust from 9 to -2 within 30s or less
3. In host:
   1. Run htop and observe NI column for sysvms and appvms
   2. Verify sysvms have a niceness value of -5, appvms 0
   3. Verify other system services have a niceness value of 5 or 0

[milva-unikie]

Tested on Lenovo X1 and Darter Pro (nixos-rebuild switch)

• As expected, the tuned-gui icon has disappeared from the app menu. Thanks!
• Launched apps get a niceness value of -2.
• Niceness values on the host match what is described in the PR.
• App launch times are not affected.
• Lenovo X1 performance test results are not showing the ~10 % decrease that was observed on Darter Pro after performance module #1542

Dell 7330

• Dell 7330 is slow, it is hitting almost every timeout in the automated tests. SSH connection times, VM boot times and app launch times are all longer. For example it takes over 3 minutes after login for the flatpak-vm to be ready for an SSH connection.
• I don't have access to the device today, but I can check the user experience tomorrow. I am assuming it is not good.
• Question: Is there a way to exclude Dell 7330 from these changes? If not, I will need to prepare a test automation patch.

Dell 7230

• Not building in Jenkins. This is a known issue unrelated to this PR. Adding a "bug" tag for that.

[kajusnau]

PR scope expanded slightly, testing instructions updated accordingly ⚠️

[Bitumiju]

https://jira.tii.ae/browse/SSRCSP-7595

[milva-unikie]

Tested on Lenovo X1 (nixos-rebuild switch)

• My Lenovo X1 gen11 crashes after ~5 minutes when running the stress test. Kajus has the details.

[kajusnau]

Reduced scope of PR - removed thermal limit changes, will be added as a separate PR.

[milva-unikie]

Tested on Darter Pro and Lenovo X1
(nixos-rebuild switch, rebased to the latest main)

Everything looks good now. tuned-gui is no longer in the app menu and the niceness values update as described in the PR.