ci: performance: reduce SWIOTLB allocation by setting swiotlb=128

[jpagadal]

The default SWIOTLB allocation of 64 MiB leads to unnecessary kernel reserved memory.

Limit the SWIOTLB pool to 2 MiB by setting swiotlb=128 in the kernel command line.
Validation confirms the allocation is reduced from 64MB to 2 MiB.

This change reduces the kernel reserved memory footprint and
improves available RAM for user space.

[github-actions]

Test run workflow

Test jobs for commit afc3609

qcom-distro
Pass: 259 | Fail: 1 | Total: 280

nodistro
Pass: 9 | Fail: 0 | Total: 9

qcom-distro_linux-qcom-6.18
Pass: 220 | Fail: 2 | Total: 249

[test-reporting-app]

Test Results

  103 files  ± 0    633 suites  +1   5h 28m 40s ⏱️ + 18m 29s
  125 tests ± 0    104 ✅  - 21   0 💤 ±0  21 ❌ +21 
6 009 runs   - 12  5 935 ✅  - 31  47 💤  - 8  27 ❌ +27 

For more details on these failures, see this check.

Results for commit afc3609. ± Comparison against base commit 8917dc1.

This pull request removes 3 and adds 3 tests. Note that renamed tests count towards both.

lava ‑ 5_OpenCV
lava ‑ 6_irq
lava ‑ 7_BT_ON_OFF

14_Kubern[ ‑ Kubernetes_Kernel_Config
lava ‑ auto-login-action
lava ‑ minimal-boot

[lumag]

Is 2 MiB enough? Do we have CONFIG_SWIOTLB_DYNAMIC enabled to get more pools if required?

Also please drop the bullet lists from the PR description. Write English text instead.

[jpagadal]

Is 2 MiB enough? Do we have CONFIG_SWIOTLB_DYNAMIC enabled to get more pools if required?

RB3Gen2, IQ8, and IQ9 devices show that /sys/kernel/debug/swiotlb/io_tlb_used is 0 and /sys/kernel/debug/swiotlb/io_tlb_used_hiwater is 4 (8 KiB). The 2 MiB value is proposed based on observations from the previous QLI release.

Additionally, a separate change has been proposed (qualcomm-linux/kernel#642) to enable CONFIG_SWIOTLB_DYNAMIC.

Also please drop the bullet lists from the PR description. Write English text instead.

Done.