2021-12-09 LDCG SC Meeting Agenda/Minutes

  Agenda

• Previous meeting minutes:  https://linaro.atlassian.net/l/c/28fqL6gc 
• New topics discussion 
• SVE2, Joakim Bech
  • Goal with the discussion:
    • Understand if there are gaps when it comes to SVE2?
    • Understand whether LDCG already is or if there is a need to get involved or involve other Linaro teams?
    • Understand what use cases there are outside HPC and ML?
    • Understand whether we've seen the benefits of vector length agnostic programming. I.e., are we running the same binaries in very different environments?
  • For reference, here is an introduction to SVE2 (link) and here is a great talk from Arm about SVE.
  • Been supported in the Linux kernel since v5.2.
  • SVE was more tailored for certain applications (ML and HPC) and was also an extension to the v8 standard.
  • SVE2 is part of the v9(?) baseline.
  • Silicon partners can choose a suitable vector length design implementation for hardware that varies between 128 bits and 2048 bits, at 128-bit increments. Mobile phone vendors might sell designs with 128-bit wide vectors, while super computer designs might support 2048-bit wide vectors.
  • Developers doesn't have to know about the vector length on their system. I.e., vector-length agnostic programming for “write once, run anywhere”.
  • The same binaries will run on different AArch64 hardware with various SVE vector length implementations.
  • Questions / discussion:
    • Compilers? Do we have the needed support?
      • GCC > 8.x supports SVE and GCC > 9.x supports SVE2
      • LLVM a bit more open ended (link)
      • Debug support.
    • Hardware / emulators?
      • QEMU has SVE support (since 3.1), but what about SVE2? Is this needed from a LDCG point of view?
      • Fast models has SVE2 support available to partners.
    • Libraries
      • Is SVE2 utilized where needed? Are the compilers doing the necessary optimizations to utilize SVE2 (SVE)?
    • Future
      • What about SME (Scalable Matrix Extension)?
• AOB

Minutes

• New LDCG SC meeting invitation for 2022 series to be sent by Joakim.  January 27, 2022 is first meeting.  
• SVE2

Action Items

• @ name action item here //dd-mm-yyyy  

Documents

• INSERT