Expiry of x86-64 patents

By: Bigos (bigos.delete@this.bigos.bigos), October 30, 2020 12:20 pm
Room: Moderated Discussions
Adrian (a.delete@this.acm.org) on October 30, 2020 12:02 pm wrote:
> Jukka Larja (roskakori2006.delete@this.gmail.com) on October 30, 2020 11:29 am wrote:
> > Mark Roulo (nothanks.delete@this.xxx.com) on October 30, 2020 10:21 am wrote:
> > > Jukka Larja (roskakori2006.delete@this.gmail.com) on October 30, 2020 9:52 am wrote:
> > > > me (me.delete@this.me.com) on October 30, 2020 9:47 am wrote:
> > > > > > And I presume you are talking about AVX2. Both PS4 and Xbox One support AVX,
> > > > > > and that alone obviously didn't gather any significant support (even though
> > > > > > consoles have much more benefit from CPU optimizations compared to PC).
> > > > > >
> > > > > > -JLarja
> > > > >
> > > > > IIRC Jaguar's AVX isn't any faster than using SSE so devs mostly ignored it I guess.
> > > >
> > > > Is any AVX faster than SSE?
> > > >
> > > > -JLarja
> > >
> > > For my employer’s loads, AVX2 runs about 1.7x faster than SSE for compute bound loads.
> >
> > Yes, but that's AVX2, which is not available on Jaguar.
> >
> > -JLarja
>
>
> Floating-point AVX operations were already 256-bit on Sandy Bridge and they had a decent
> speed increase over SSE, approaching double speed for favorable cases, like GEMM.
>
> AVX2 of Haswell extended to 256-bit also the integer operations, simultaneous with the introduction
> of FMA, which could provide another doubling of the floating-point throughput.
>
>
> So even with simple AVX, without AVX2 & FMA, like in Sandy Bridge/Ivy Bridge, the floating-point
> speed should be better, except for small CPUs (like presumably in Jaguar), which might cheat and
> implement AVX just for compatibility, without actually doubling the floating-point throughput.

I believe Haswell also enwidened the load/store data paths from 128-bit to 256-bit. This might also contribute to higher AVX gains for FP32 code between Haswell and Sandy Bridge.

Though I agree that what Jaguar gave with AVX support is the ISA benefits (like 3-register instructions) and not performance. Now Zen2 has full AVX2 support with 256-bit data paths in both the ALUs and load/store and L1d cache.
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TopicPosted ByDate
Expiry of x86-64 patentsBeastian2019/04/19 08:05 AM
  Expiry of x86-64 patentsGian-Carlo Pascutto2019/04/19 08:46 AM
    Expiry of x86-64 patentsBeastian2019/04/19 09:06 AM
    Expiry of x86-64 patentsJukka Larja2019/04/19 09:44 AM
      Expiry of x86-64 patentsGian-Carlo Pascutto2019/04/19 10:12 AM
        Expiry of x86-64 patentsJukka Larja2019/04/19 11:41 AM
          Expiry of x86-64 patentsRobert Williams2019/04/19 12:18 PM
          Expiry of x86-64 patentsGian-Carlo Pascutto2019/04/19 01:35 PM
          Expiry of x86-64 patentsIntelUser20002020/10/30 01:17 AM
            Expiry of x86-64 patentsJukka Larja2020/10/30 06:49 AM
              Expiry of x86-64 patentsme2020/10/30 08:47 AM
                Expiry of x86-64 patentsJukka Larja2020/10/30 08:52 AM
                  Expiry of x86-64 patentsMark Roulo2020/10/30 09:21 AM
                    Expiry of x86-64 patentsJukka Larja2020/10/30 10:29 AM
                      Expiry of x86-64 patentsMark Roulo2020/10/30 10:42 AM
                        Expiry of x86-64 patentsJukka Larja2020/10/30 08:04 PM
                          SIMD syntaxhobold2020/10/31 05:54 AM
                            SIMD syntaxJukka Larja2020/10/31 08:14 AM
                              SIMD syntaxhobold2020/11/01 07:22 AM
                                SIMD syntaxJukka Larja2020/11/01 10:11 AM
                                  SIMD syntaxhobold2020/11/02 04:33 AM
                          Expiry of x86-64 patentsme2020/10/31 02:01 PM
                            Expiry of x86-64 patentsJukka Larja2020/10/31 08:23 PM
                              Expiry of x86-64 patentsFoo_2020/11/01 03:48 AM
                                Expiry of x86-64 patentsJukka Larja2020/11/01 06:01 AM
                      Expiry of x86-64 patentsAdrian2020/10/30 11:02 AM
                        Expiry of x86-64 patentsBigos2020/10/30 12:20 PM
      Expiry of x86-64 patentsGeoff Langdale2019/04/19 01:52 PM
        Expiry of x86-64 patentsJukka Larja2019/04/19 08:38 PM
      Expiry of x86-64 patentsYuhong Bao2019/04/20 01:35 PM
  Expiry of x86-64 patentsDoug S2019/04/19 09:40 AM
    Expiry of x86-64 patentsBeastian2019/04/19 10:10 AM
      Expiry of x86-64 patentsRobert Williams2019/04/20 07:15 AM
        Expiry of x86-64 patentsRobert Williams2020/10/28 05:42 AM
  Expiry of x86-64 patentsanyone2019/04/20 06:11 AM
    Expiry of x86-64 patentsGroo2019/04/20 06:29 AM
      Expiry of x86-64 patentswumpus2019/04/20 07:32 AM
      Expiry of x86-64 patentsblaine2020/10/30 11:03 AM
        Expiry of x86-64 patentsDavid Kanter2020/10/30 07:59 PM
  Intel vs AMD patentsYuhong Bao2019/04/20 01:32 PM
    Intel vs AMD patentsBeastian2019/04/20 02:35 PM
  Expiry of x86-64 patentsTravis Downs2019/04/20 06:24 PM
    Expiry of x86-64 patentsnone2019/04/21 06:36 AM
      Expiry of x86-64 patentssomebody2019/11/27 09:44 AM
      Expiry of x86-64 patentsAnon32019/11/27 04:16 PM
        Expiry of x86-64 patentsTravis Downs2019/11/27 05:17 PM
      Expiry of x86-64 patentsMontaray Jack2019/11/27 11:03 PM
        Expiry of x86-64 patentsnone2019/11/28 12:57 AM
          Expiry of x86-64 patentsdmcq2019/11/28 10:20 AM
            Expiry of x86-64 patentsMontaray Jack2019/11/29 04:00 AM
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