[AMD Public Use]
> That's deliberate, so that we can use the same x86-* names for 32-bit library > selection (once we define matching micro-architecture levels there). Understood. > If numbers are out, what should we use instead? > x86-sse4, x86-avx2, x86-avx512? Would that work? Yes please, I think we have to choose somewhere, above would be more descriptive > Let's merge Level B into level C then? I would vote for this. >> Also we would also like to have dynamic loader support for "zen" / >> "zen2" as a version of "Level D" and takes preference over Level D, >> which may have super-optimized libraries from AMD or other vendors. > *That* shouldn't be too hard to implement if we can nail down the selection > criteria. Let's call this Zen-specific Level C x86-zen-avx2 for the sake of > exposition. Some way of specifying a superset of "level C" , that "C" will capture fully. Zen/zen2 takes precedence over Level C, but not Level D, but falls back to "Level C" or "x86-avx2" but not "x86-avx". I think it is better to run a x86-zen on a x86-avx2 or x86-avx compared to running on a base x86_64 config. > With the levels I proposed, these aspects are covered. But if we start to > create vendor-specific forks in the feature progression, things get > complicated. I am not strictly proposing OS vendors should create/maintain this (it would be nice if they did), but a support to cached load via system-wide-config. This directory may/will contain a subset of system libs. > Do you think we need to figure this out in this iteration? If yes, then I > really need a semi-formal description of the selection criteria for this > x86-zen-avx2 directory, so that I can passed it along with my psABI proposal. Preference level (decreasing order) (I can only speak for AMD, others please pitch in) - system wide config to override (in this case x86-zen) - x86-avx2 - x86-sse4 (or avx, based on how we name and merge Level B) - default x86_64
