Record bios/host/guest options in a reliable way

[mmisono]

For better reproducibility, we should record related bios and host/guest kernel options.

What to record

• generic machine info (CPU, memory, device, ...)
• if bounce buffer enabled
• if iommu enabled
• ...

Where to check

• dmesg
• msr
• cpuid
• /proc/cpuinfo
• /sys/firmware/acpi/
• /sys/firmware/tdx/tdx_module
• /dev/(sev|tdx)-(guest|host)

SEV-SNP

• https://github.com/rcastellotti/gr/blob/ea72e3c9f21d1a9bf409285e86baf0a349bacec9/report/main.tex#L83C15-L83C15

TDX

• tdx-tools has several scripts for checking host/guest status
  • check-tdx-host.sh
  • check-tdx-guest.sh

TODO

• How to get BIOS settings (IPMI?)

[enterJazz]

BIOS Config Changes

for benchmarking reproducbility, we adopt the BIOS changes from John Kariuki, Vishal Verma, & Roman Sudarikov - Best Practices: Performance Testing & Tuning:

Turbo Mode

• set turbo: disabled

Hyperthreading

• set logical processor: disabled

C-States, P-States

• set C-States: disabled
• set CPU Power Management: Max performance -> disables P-States
• set DF Cstate: disabled
• set DF Pstate: disabled

Memory Speed

• set memory frequency: max performance
• NOTE: other options may still be available here ( todo )

Node Interleaving

• should be disabled by default ( as system displays NUMA nodes )
• could possibly set explicitly somewhere ( NOTE: todo )

Power

• set CPU Power Management: Max performance
• NOTE: other options may still be available here

Misc

• set memory frequency: max performance
• set power profile: max io performance mode
• set determinism slider: performance

SEV Specific

• set SME: enabled
• set SNP: enabled
• set SNP memory coverage: enabled
• Minimum SEV non-ES ASID: 100 (not 1 -> 1 = no SEV ASID)
• Kernel DMA Protectino: enabled ( from https://arkivm.github.io/sev/2022/11/25/running-amd-svsm/ )

NOTE

We configured the BIOS manually. Down the line, we should create a script to ssh into the IPMI and set these changes automatically.

Also mentioned in README