2021-3-22 Meeting Meeting notes

Topic: linaro-open-discussion meeting
Time: March 22 , 2021 10.00 AM London

Join Zoom Meeting
https://linaro-org.zoom.us/j/4417312160

Meeting ID: 441 731 2160
One tap mobile
+16465588656,,4417312160# US (New York)
+16699009128,,4417312160# US (San Jose)

Dial by your location
+1 646 558 8656 US (New York)
+1 669 900 9128 US (San Jose)
+1 253 215 8782 US (Tacoma)
+1 301 715 8592 US (Washington D.C)
+1 312 626 6799 US (Chicago)
+1 346 248 7799 US (Houston)
877 853 5247 US Toll-free
888 788 0099 US Toll-free
Meeting ID: 441 731 2160
Find your local number: https://linaro-org.zoom.us/u/aUcYpPkSC

• Lorenzo

• Vincent

• Jammy

• James Morse

• Souvik Chakravarty

• Jonathan

• Jean-Philippe

• Shameerali

• Salil

• Barry Song

• Yunsheng Lin

• Tao Zeng

• CXL on memory (Jonathan presented several new slides after the introduction in last call)

•  

  • Handling of memory on Type 2 devices (like GPU), two modes:

    • Host biased (coherency is managed as part of the host SoC)

    • Device biased (device issues coherence messages)

  • Vikram's question: how should it be presented by Firmware?

    • Problem 1: normal memory at boot can't be offlined later

      • Likely to need element of BIOS control

    • Problem 2: pinned memory in region

      • Patch sets under review to migrate memory out of ZONE_MOVABLE on pin

  • Generic Initiator Reminder

  • GI as bridge for CXL etc.

    • https://lore.kernel.org/linux-acpi/CAPcyv4gmd_cygXK0PpGkXmJLC3_ctEpRvpi5P-QcuXusFX5oNQ@mail.gmail.com/

• Virtual CPU hotplug

•  

  • Salil shared some figures about QEMU boot time impact by the number of CPU cores

    • Pre vCPU Init

    • Post vCPU Init (but pre-VGIC Init)

    • Post VGIC Init

    • Pre Linux Kernel Load

    • Post Kernel Load (But Pre SMBIOS setup)

  • LP: we need to converge and do some wrap up for proposal

    • Salil to share some details about how to get the figures

• Recording: link (password: *92a8xSE)