Current Situation

Codes used within ETMC

  • tmLQCD linked with DD\(\alpha\)AMG and QPhiX for gauge generation

  • QUDA, DD\(\alpha\)AMG for propagator generation linked to several packages (paramgen, plegma, Nissa, …)

  • contraction tools: cvc, plegma and many more

Architecture Development

Currently, we have

  • GPU based machines (mostly clusters and PizDaint)

  • CPU based machines (SuperMUC, JUWELS, …)

in the future

  • likely large GPU installation in J├╝lich

  • a new, likely ARM based, European architecture

Code Efficiency

  • complicated vector pipeline and many threads

  • peak performance of machines increasing further and further

  • however, code efficiency is decreasing if no significant amount of programming and optimisation is invested

  • and optmisations need to be done again and again

one would like to have a general enough code to easily adopt to new architectures

Architecture Development

If we don't adopt, we risk to loose

  • the ability to generate state of the art gauge configs

  • our ability for innovations

  • our competitiveness

The fate of tmLQCD

  • tmLQCD becomes more and more difficult to adopt to new realities

  • it would require a completely new memory management

  • and a completely new data layout

  • likely not possible with tmLQCD, as it is a C-code

  • tmLQCD is the only package supporting twisted 2+1+1 dynamically

Wishlist

  • HMC gauge configuration generation with
    • Wilson twisted clover
    • 2+1+1 flavours
    • smearing
  • propagator generation

  • on the fly contractions

  • reasonably optimised kernels for general architectures for all these tasks

  • else?

Options

  • start a completely new code suite

  • hook up with existing project
    • grid
    • Chroma
    • else?
  • extend Plegma or tmLQCD

  • else?

Any of these requires a dedicated effort and a lot of manpower!

my opinion: need a good compromise between efficiency, flexibility and effort!