Cortex-A72 Technical Reference Manual

By: juanrga (nospam.delete@this.juanrga.com), March 7, 2015 5:16 am
Room: Moderated Discussions
David Kanter (dkanter.delete@this.realworldtech.com) on March 7, 2015 12:43 am wrote:
> Wilco (Wilco.Dijkstra.delete@this.ntlworld.com) on March 6, 2015 2:31 pm wrote:
> > Brett (ggtgp.delete@this.yahoo.com) on March 6, 2015 12:57 pm wrote:
> > > David Kanter (dkanter.delete@this.realworldtech.com) on March 6, 2015 12:42 am wrote:
> > > > > A57 is definitely more than 20% faster at the same clock, as you can easily conclude
> > > > > from various benchmarks (eg. Geekbench shows 40% single threaded gain overall
> > > > > in AArch32 mode between Galaxy S5 and Galaxy S6 at the same clock).
> > > >
> > > > That's a bogus comparison since Geekbench contains lots of AES
> > > > stuff, and ARM64 contains special instructions for AES.
> > >
> > > Are you accusing ARM of pulling an Intel, making sure that benchmarks are dominated
> > > by feature X right before Intel adds feature X to the instruction set. ;)
> > >
> > > This tactic is old hat, blatantly obvious for over a decade. Happy
> > > to see that ARM is playing by the rules of the CPU market.
> >
> > Yeah ARM is to blame, after all Intel only added AES early 2010...
>
> I'm not blaming anyone. I'm saying it's ridiculous to make inferences about general performance using benchmarks
> that are skewed by the presence of AES instructions (that goes for any designs, not just ARM).
>
> > > > What's the speedup on GCC?
> > >
> > > GCC is the worst pointer chasing spaghetti on the planet. You have to brute force tweak hundreds
> > > of CPU details so as not to get burned by one of a hundred glass jaws that will cripple your
> > > performance. This takes billions of dollars that AMD does not have, much less tiny ARM.
> > >
> > > Unless IBM gets into the ARM64 business Intel is going to dominate the GCC comparison
> > > for the next two decades, longer than I expect Intel to survive as dominate company.
> > > $15 SOC's don't generate the sort of revenues that justify optimizing for GCC.
> >
> > GCC is a hard benchmark indeed but it's not going to cost billions of dollars to design next
> > generation CPUs that do better. Did Athlon64 cost billions? All it took was a brilliant design
> > and a great team to make it happen. The trend is obvious, each new generation of ARM cores improves
> > by 30-50%. I wonder what would happen if say the Athlon64 designer does an ARM...
>
> The IPC for ARM cores is improving much more slowly than that.

How much is improving then? 1%? 10%?

And what do you mean by ARM cores? Only Cortex? Because Nvidia did increase integer IPC by 50% in A15-->Denver.

> It's also hard to discuss the overall
> performance since ARM doesn't control the power management, process, memory controller, etc.
>
> David
>
> PS: I sent you an email about compiler settings in benchmarks.

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Cortex-A72 Technical Reference ManualRonald Maas2015/03/05 07:01 AM
  Cortex-A72 Technical Reference Manualdmcq2015/03/05 10:01 AM
  Cortex-A72 Technical Reference ManualAlberto2015/03/05 10:06 AM
    Cortex-A72 Technical Reference ManualExophase2015/03/05 11:57 AM
      Cortex-A72 Technical Reference ManualAlberto2015/03/06 09:45 AM
        Cortex-A72 Technical Reference ManualWilco2015/03/06 11:49 AM
          Cortex-A72 Technical Reference ManualAlberto2015/03/06 01:09 PM
            Cortex-A72 Technical Reference ManualWilco2015/03/07 08:37 AM
          Cortex-A72 Technical Reference Manualjuanrga2015/03/06 05:18 PM
    Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/05 02:40 PM
      Cortex-A72 Technical Reference ManualWilco2015/03/05 03:28 PM
        Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/05 11:32 PM
        Cortex-A72 Technical Reference ManualDavid Kanter2015/03/05 11:42 PM
          Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/06 01:55 AM
            Cortex-A72 Technical Reference Manualnone2015/03/06 02:36 AM
              Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/06 03:08 AM
                Cortex-A72 Technical Reference Manualnone2015/03/06 03:12 AM
                Cortex-A72 Technical Reference ManualWilco2015/03/06 03:39 AM
          Cortex-A72 Technical Reference ManualWilco2015/03/06 04:04 AM
            Cortex-A72 Technical Reference Manualnone2015/03/06 04:50 AM
              Cortex-A72 Technical Reference ManualWilco2015/03/07 08:26 AM
                Cortex-A72 Technical Reference Manualnone2015/03/09 12:10 AM
                  Cortex-A72 Technical Reference Manualdmcq2015/03/09 01:14 AM
                    Cortex-A72 Technical Reference Manualnone2015/03/09 01:53 AM
          Cortex-A72 Technical Reference ManualBrett2015/03/06 11:57 AM
            Cortex-A72 Technical Reference ManualKlimax2015/03/06 12:39 PM
            Cortex-A72 Technical Reference ManualExophase2015/03/06 01:22 PM
            Cortex-A72 Technical Reference ManualWilco2015/03/06 01:31 PM
              Cortex-A72 Technical Reference Manualjuanrga2015/03/06 05:22 PM
                Broadcom VulcanBrett2015/03/07 01:56 PM
                  Broadcom Vulcananon2015/03/07 04:01 PM
                    Broadcom VulcanAnon2015/03/07 05:43 PM
                      Broadcom VulcanBrett2015/03/07 08:10 PM
                        Broadcom VulcanMichael S2015/03/08 01:30 AM
                          Broadcom VulcanGabriele Svelto2015/03/08 03:55 AM
                    Broadcom VulcanHugo Décharnes2015/03/08 12:47 AM
                      Broadcom VulcanExophase2015/03/08 10:58 AM
                  Broadcom Vulcanjuanrga2015/03/07 06:06 PM
                    Broadcom VulcanBrett2015/03/07 08:26 PM
                      Broadcom Vulcanjuanrga2015/03/08 05:48 AM
                        Broadcom VulcanBrett2015/03/30 05:50 PM
                          Broadcom Vulcandmcq2015/03/31 03:33 AM
                  Broadcom VulcanDavid Kanter2015/03/08 01:46 AM
                    Broadcom VulcanGabriele Svelto2015/03/08 03:57 AM
                    Broadcom Vulcanjuanrga2015/03/08 06:12 AM
              Cortex-A72 Technical Reference ManualDavid Kanter2015/03/06 11:43 PM
                Cortex-A72 Technical Reference Manualjuanrga2015/03/07 05:16 AM
                Cortex-A72 Technical Reference ManualWilco2015/03/07 08:50 AM
                  Cortex-A72 Technical Reference ManualDavid Kanter2015/03/08 01:30 AM
                    Cortex-A72 Technical Reference ManualMichael S2015/03/08 03:14 AM
                    Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/08 03:26 AM
                      Cortex-A72 Technical Reference Manualjuanrga2015/03/08 05:51 AM
                        Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/08 06:08 AM
                    Cortex-A72 Technical Reference ManualKlimax2015/03/08 07:44 AM
                  Cortex-A72 Technical Reference ManualGabriele Svelto2015/03/08 03:01 AM
              Cortex-A72 Technical Reference Manualanon2015/03/07 10:41 AM
            Cortex-A72 Technical Reference ManualDavid Kanter2015/03/06 11:37 PM
              Cortex-A72 Technical Reference ManualExophase2015/03/06 11:45 PM
              Cortex-A72 Technical Reference ManualJouni Osmala2015/03/07 01:54 AM
              Cortex-A72 Technical Reference Manualhashhash2015/03/07 06:06 AM
      Cortex-A72 Technical Reference Manualnone2015/03/05 11:36 PM
        Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/06 01:47 AM
          Cortex-A72 Technical Reference Manualnone2015/03/06 02:29 AM
            Cortex-A72 Technical Reference ManualHugo Décharnes2015/03/06 03:02 AM
        Cortex-A72 Technical Reference Manualjuanrga2015/03/06 08:38 AM
          Cortex-A72 Technical Reference ManualJouni Osmala2015/03/06 09:27 AM
      Cortex-A72 Technical Reference ManualAlberto2015/03/06 09:58 AM
        Cortex-A72 Technical Reference ManualExophase2015/03/06 10:52 AM
          Cortex-A72 Technical Reference ManualAlberto2015/03/06 02:30 PM
            Cortex-A72 Technical Reference Manualjuanrga2015/03/06 05:32 PM
            Cortex-A72 Technical Reference ManualRonald Maas2015/03/06 07:11 PM
              Cortex-A72 Technical Reference ManualAlberto2015/03/07 05:52 AM
                Cortex-A72 Technical Reference ManualRonald Maas2015/03/07 08:52 AM
  Cortex-A72 Technical Reference ManualNoSpammer2015/03/05 11:33 AM
  Add two more differences.Jouni Osmala2015/03/05 02:13 PM
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