Hi, On Tue, Aug 17, 2021 at 3:27 PM James Almer <jamr...@gmail.com> wrote:
> On 8/17/2021 4:24 PM, James Almer wrote: > > On 8/17/2021 12:25 PM, Ronald S. Bultje wrote: > >> On Tue, Aug 17, 2021 at 2:33 AM Hendrik Leppkes <h.lepp...@gmail.com> > >> wrote: > >>> On Tue, Aug 17, 2021 at 8:30 AM Wu Jianhua <jianhua...@intel.com> > wrote: > >>>> Based on IceLake-AVX512 and newer architecture, a broad > >>>> range of the subsets of AVX512 could be supported. > >> [..] > >>>> - enabled avx512 && check_x86asm avx512_external "vmovdqa32 > >>> [eax]{k1}{z}, zmm0" > >>>> + # Only IceLake and newer architectures could enable AVX512 > >>>> + # > >>> > F/CD/BW/DQ/VL/VNNI/IFMA/VBMI/VBMI2/VPOPCNTDQ/BITALG/GFNI/VAES/VPCLMULQDQ > >>>> + enabled avx512 && check_x86asm avx512_external "vpdpwssds > >>> zmm31{k1}{z}, zmm29, zmm28" > >>>> enabled avx2 && check_x86asm avx2_external "vextracti128 > >>> xmm0, ymm0, 0" > >>>> enabled xop && check_x86asm xop_external "vpmacsdd > >>>> xmm0, > >>> xmm1, xmm2, xmm3" > >>>> enabled fma4 && check_x86asm fma4_external "vfmaddps > >>>> ymm0, > >>> ymm1, ymm2, ymm3" > >>> > >>> Note that you are just checking the functionality of the assembler > >>> here, not having a runtime impact. > >>> What you would likely want is to update avutil/x86/cpu.c as well to > >>> only enable the AVX512 flag on those CPUs. > >> > >> [After IRC discussion] you want runtime checks for the > >> variants/combinations-of-subsets that we want to support. Right now, > >> avx512 > >> means skylake, so you may want to rename that flag to "avx512skl", and > >> add > >> a new runtime flag + check for the icelake subset called "avx512icl". > >> Then > >> in your implementations, you use the appropriate flag, and code > >> components > >> can individually choose to use skylake- and/or icelake-optimized ax512 > >> functions. > [..] > > What about just making the existing AVX512 flag mean F+VL+DQ+BW, so > > Skylake-X (Anything older just lacks useful instructions for > > multimedia), and if needed for this new code add a new avx512icl flag > > that also looks for something like GFNI. > > Assuming making Ice Lake the minimum supported SKU is not acceptable, > then your suggestion is fine (Sans the renaming, since it's a breaking > change). > Yes, agreed. Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".