Itanium also used it

By: David Kanter (, January 22, 2020 2:04 pm
Room: Moderated Discussions
Gabriele Svelto ( on January 22, 2020 12:40 pm wrote:
> Travis Downs ( on January 16, 2020 8:20 pm wrote:
> > Here's a draft of a blog entry I'll post fully tomorrow:
> >
> >
> >
> > Feedback, including frank feedback about things that are confusing or pointless, free
> > proofreading, whatever is welcome. Reply here or by email or whatever you want.
> >
> > Please don't repost this anywhere other than RWT for the moment, that's for tomorrow.
> >
> > Ignore TODOs, I'll fix them tomorrow.
> Sorry if I'm late to the party but it was a really good article and I needed
> some time to read it all. First of all congratulations, it was excellent!
> I believe that your hypothesis that the first slow-down is caused by throttling dispatch
> has some merit because there's precedent for that on another processor. Straight
> from POWER9's user manual section "Voltage Droop Protection":
[...] Lastly, if a droop event begins to approach operational VMIN in an extreme
> case, the core can be configured to temporarily throttle back instruction fetch
> and issue in the processor cores as an emergency protection measure.
IIRC POWER8 had something similar and I seem to remember reading about that in Fujitsu's
> A64FX slides too. It might be a common technique; it certainly have the advantage
> of providing a very fast, very fine-grained way of reducing dynamic power.

Some Itanium processors would reduce Cdyn by only issuing one bundle per clock.

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TopicPosted ByDate
AVX-512 downclocking postTravis Downs2020/01/16 09:20 PM
  AVX-512 downclocking postanon³2020/01/17 01:25 AM
    AVX-512 downclocking postAndrei2020/01/17 02:47 AM
      AVX-512 downclocking postMontaray Jack2020/01/17 03:58 PM
        AVX-512 downclocking postAndrei2020/01/17 11:40 PM
          AVX-512 downclocking postMontaray Jack2020/01/19 02:10 AM
            AVX-512 downclocking postJan Olšan2020/01/19 01:01 PM
              AVX-512 downclocking postJan Olšan2020/01/19 01:11 PM
    AVX-512 downclocking postTravis Downs2020/01/17 02:59 PM
    AVX-512 downclocking postDavid Kanter2020/01/18 10:27 AM
      magnetic inductorsjokerman2020/01/18 08:03 PM
      AVX-512 downclocking postTravis Downs2020/01/24 11:36 AM
  AVX-512 downclocking postRay2020/01/17 02:22 AM
    AVX-512 downclocking postTravis Downs2020/01/17 01:10 PM
  AVX-512 downclocking postEtienne2020/01/17 03:16 AM
    Thanks, typos fixed and credited (NT)Travis Downs2020/01/17 01:15 PM
  Title suggestions welcome (NT)Travis Downs2020/01/17 08:54 AM
  AVX-512 downclocking postanonymou52020/01/17 10:53 AM
    AVX-512 downclocking postTravis Downs2020/01/17 11:14 AM
      AVX-512 downclocking postYoav2020/01/17 11:50 AM
        AVX-512 downclocking postTravis Downs2020/01/17 01:14 PM
      AVX-512 downclocking postanonymou52020/01/17 04:26 PM
        AVX-512 downclocking postTravis Downs2020/01/22 08:19 PM
          AVX-512 downclocking postanonymou52020/01/23 12:56 AM
            AVX-512 downclocking postFoyle2020/01/23 05:51 AM
              AVX-512 downclocking postanonymou52020/01/23 06:57 AM
                AVX-512 downclocking postTravis Downs2020/01/24 12:49 PM
            finer-grained licensesTravis Downs2020/01/24 01:03 PM
              finer-grained licensesanonymou52020/01/24 04:28 PM
                finer-grained licensesTravis Downs2020/01/25 09:46 AM
  post published (new line)Travis Downs2020/01/17 11:55 AM
    should say: (new LINK) (NT)Travis Downs2020/01/17 11:55 AM
      should say: (new LINK)Tim McCaffrey2020/01/17 01:44 PM
        Thanks, fixed and credited (NT)Travis Downs2020/01/17 02:54 PM
      should say: (new LINK)anon2020/01/17 09:12 PM
        should say: (new LINK)Travis Downs2020/01/22 03:28 PM
          Thanks!anon2020/01/22 08:06 PM
            Thanks!Travis Downs2020/01/22 08:16 PM
              Thanks!anon2020/01/22 10:20 PM
                Thanks!Travis Downs2020/01/23 01:51 AM
                  Thanks!Linus Torvalds2020/01/23 05:33 PM
                    Thanks!Travis Downs2020/01/24 12:44 PM
  Throttling dispatchGabriele Svelto2020/01/22 01:40 PM
    Itanium also used itDavid Kanter2020/01/22 02:04 PM
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