Independent micro threads

By: Doug S (foo.delete@this.bar.bar), January 1, 2019 12:40 am
Room: Moderated Discussions
David Hess (davidwhess.delete@this.gmail.com) on December 31, 2018 8:32 pm wrote:
> Doug S (foo.delete@this.bar.bar) on December 31, 2018 9:26 am wrote:
> > David Hess (davidwhess.delete@this.gmail.com) on December 30, 2018 6:26 pm wrote:
> > >
> > > The die price (size) problem has puzzled me for a while. For thermally limited designs which
> > > have a die smaller than can be produced, couldn't a higher clock speed be achieved be deliberately
> > > using a lower transistor density for a lower junction to case thermal resistance at the cost
> > > of higher power? I do not know of anybody doing it though or at least admitting it.
> >
> > What's the cause of hitting that thermal limit, it is a lack of ability to remove heat from a specific sq
> > mm or few sq mm, or is it the lack of ability to remove heat from the entire package? For the former what
> > you suggest will work, for the latter you upgrade to water cooling etc. to remove heat more quickly.
>
> It is the former which is why thermal management tracks power and temperature of different areas. One thing
> which would help is better materials for heat spreaders but they are all much more expensive than copper or
> even silver. A directly attached heat pipe would be ideal but the power density is much greater than a heat
> pipe will support except in low power applications some of which do use a directly attached heat pipe.
>
> I had not considered it before but a lot of the performance gain or rather lack of performance
> loss with denser processes since integrated temperature sensing was first used comes from monitoring
> temperature and power at many points instead of the average temperature which explains why so
> much effort is put into it. It is the peak temperatures and hot spots which matter.


OK, but think about the possible sources of these hot spots. Where is the most activity on a modern CPU in the average case - probably the register file and ALUs (there are other places that might be like branch unit, ROB and so forth but the register file and ALUs will ALWAYS be hot)

Those are essentially pinpoint sources in a modern CPU core - far less than 1 sq mm. If you spread out the transistors to take (just as an example) a 0.25 sq mm area to 2.5 sq mm you now have longer wires. How much power does that waste? Does it affect your cycle time, since registers are now "further away" from the ALUs? If it does, you may lose the chance for the higher clock rates you were hoping to attain by spreading things out.
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TopicPosted ByDate
Independent micro threadsBrett2018/12/30 01:55 PM
  Independent micro threadsTravis Downs2018/12/30 04:18 PM
    Independent micro threadsBrett2018/12/30 07:16 PM
      Independent micro threadsTravis Downs2018/12/30 07:34 PM
        Independent micro threadsBrett2018/12/30 07:48 PM
          Independent micro threadsTravis Downs2018/12/30 09:06 PM
            Independent micro threadsBrett2018/12/30 10:57 PM
              Independent micro threadsTravis Downs2018/12/31 12:42 AM
                Independent micro threadsBrett2019/01/01 07:02 PM
                  Independent micro threadsMichael S2019/01/02 02:01 AM
                    Independent micro threadsMaynard Handley2019/01/02 03:29 PM
              Independent micro threadsMontaray Jack2019/01/01 02:12 AM
  Independent micro threadsanon2018/12/30 04:34 PM
  Independent micro threadsPaul A. Clayton2018/12/30 05:15 PM
  Independent micro threadsDavid Hess2018/12/30 06:47 PM
    Independent micro threadsDomaldel2018/12/30 07:06 PM
      Independent micro threadsDavid Hess2018/12/30 07:26 PM
        Independent micro threadsDoug S2018/12/31 10:26 AM
          Independent micro threadsDavid Hess2018/12/31 09:32 PM
            Independent micro threadsDoug S2019/01/01 12:40 AM
              Independent micro threadsDavid Hess2019/01/01 11:41 AM
            Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:40 AM
              Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:44 AM
                Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:49 AM
                  Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 12:51 AM
              Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Simon Farnsworth2019/01/01 06:05 AM
                Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Domaldel2019/01/01 08:01 AM
                Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")Maynard Handley2019/01/01 01:17 PM
                  Taking things to extremes.Domaldel2019/01/01 05:44 PM
                    Yes, I know, the forum is named *Real* World Tech, but I'm thinking that perhapsDomaldel2019/01/01 05:52 PM
                      Yes, I know, the forum is named *Real* World Tech, but I'm thinking that perhapsMontaray Jack2019/01/02 07:26 AM
                        Yes, I know, the forum is named *Real* World Tech, but I'm thinking that perhapsMontaray Jack2019/01/02 08:21 AM
                    Taking things to extremes.Maynard Handley2019/01/01 06:55 PM
                    Taking things to extremes.Kevin G2019/01/04 08:57 AM
              Overcomming thermal limits of a high dencity 3D arcitecture (Formerly "Independent micro threads")David Hess2019/01/01 11:36 AM
    Independent micro threadsTravis Downs2018/12/30 07:38 PM
    Independent micro threadsBrett2018/12/30 07:41 PM
  Independent micro threadsanon2018/12/30 08:20 PM
    Independent micro threadsBrett2018/12/30 08:51 PM
      Independent micro threadsTravis Downs2018/12/30 09:48 PM
        Mill and Independent micro threadsBrett2019/01/01 07:39 PM
          No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Heikki Kultala2019/01/02 12:29 AM
            No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Brett2019/01/02 01:15 AM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Heikki Kultala2019/01/02 02:22 AM
                No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Brett2019/01/03 01:13 AM
                  "Leaf branch" is not a commonly used termHeikki Kultala2019/01/03 03:48 AM
                    "Leaf branch" is not a commonly used termBrett2019/01/03 04:35 AM
                      You lack parallelism than OoOE givesHeikki Kultala2019/01/03 07:38 AM
                        You lack parallelism than OoOE givesBrett2019/01/04 02:41 AM
                          You lack parallelism than OoOE givesBrett2019/01/04 04:10 PM
                            You lack parallelism than OoOE givesBrett2019/01/05 08:29 PM
                              Mill speculates, more parallelism than OoOE givesBrett2019/01/05 08:31 PM
                                Mill *is* a speculationEric Bron2019/01/06 05:04 AM
                                  Mill *is* a speculationMichael S2019/01/06 05:53 AM
                                    Mill *is* a speculationBrett2019/01/06 09:03 PM
                                  Mill *is* a speculationjuanrga2019/01/06 06:10 AM
                                    probably ~2 (NT)Michael S2019/01/06 06:51 AM
                                  Mill *is* a speculationBrett2019/01/06 01:18 PM
                                    Mill *is* a speculationEric Bron2019/01/06 03:36 PM
                                      Mill *is* a speculationBrett2019/01/06 08:47 PM
                                        Mill *is* a speculationJacob Marley2019/01/06 10:29 PM
                                          Mill *is* a speculationBrett2019/01/07 04:24 AM
                                            Mill *is* a speculationMichael S2019/01/07 05:23 AM
                                            Mill *is* a speculationEric Bron2019/01/07 05:36 AM
                                              Mill *is* a speculationBrett2019/01/07 03:40 PM
                                                Mill *is* a speculationEric Bron2019/01/07 05:32 PM
                                            Mill is something you don't understandHeikki Kultala2019/01/08 04:19 AM
                                              Mill is something you don't understandMichael S2019/01/08 07:44 AM
                                                Itanium and static vs dynamicHeikki Kultala2019/01/09 03:14 AM
                                                  Itanium and static vs dynamicPaul A. Clayton2019/01/09 08:51 AM
                                        Mill *is* a speculationEric Bron2019/01/07 05:27 AM
                                          Mill *is* a speculationEric Bron2019/01/07 06:23 AM
                                      Mill *is* a speculationanon2019/01/07 06:24 AM
                                        Mill *is* a speculationEric Bron2019/01/07 06:52 AM
                                          Mill *is* a speculationanon2019/01/07 08:36 AM
                                            Mill *is* a speculationEric Bron2019/01/07 09:20 AM
                                        Mill *is* a speculationjuanrga2019/01/07 10:22 AM
                                          Mill *is* a speculationanon2019/01/07 01:16 PM
                                        Mill *is* a speculationanon2019/01/07 09:46 PM
                                          Mill *is* a speculationanon2019/01/08 01:56 AM
                                            Mill *is* a speculationanon2019/01/08 03:39 AM
                                              Mill *is* a speculationMichael S2019/01/08 03:52 AM
                                                Mill *is* a speculationanon2019/01/08 10:10 PM
                                                  Wasted width not wasted work.Brett2019/01/09 11:44 AM
                                                    No such thing was declared. (NT)anon2019/01/09 03:41 PM
                                                    Very simple test for new uarch ideassomeone2019/01/10 07:03 AM
                                                      Very simple test for new uarch ideasdmcq2019/01/10 07:21 AM
                                                        Very simple test for new uarch ideasDoug S2019/01/10 10:01 AM
                                                          Very simple test for new uarch ideasDan Fay2019/01/10 01:13 PM
                                                      Very simple test for new uarch ideasanonymous22019/01/10 11:03 AM
                                                        Very simple test for new uarch ideasAlberto2019/01/10 11:32 AM
                                                      Very simple test for new uarch ideasEtienne2019/01/11 03:03 AM
                                                        Very simple test for new uarch ideasFoo_2019/01/11 04:31 AM
                                                          Very simple test for new uarch ideasEtienne2019/01/11 05:51 AM
                                                            Very simple test for new uarch ideasFoo_2019/01/11 05:53 AM
                                                              Very simple test for new uarch ideasdmcq2019/01/11 06:08 AM
                                                              Very simple test for new uarch ideasEtienne2019/01/11 06:13 AM
                                                                Very simple test for new uarch ideasFoo_2019/01/11 06:54 AM
                                                                  Very simple test for new uarch ideasEtienne2019/01/11 07:32 AM
                                                                    Very simple test for new uarch ideasBrett2019/01/11 10:25 AM
                                                                      Very simple test for new uarch ideasMegol2019/01/12 06:29 AM
                                                                        Very simple test for new uarch ideasMichael S2019/01/12 09:21 AM
                                                                          Word salad AI fundamentaliy brokenBrett2019/01/12 01:59 PM
                                                                          Very simple test for new uarch ideasMegol2019/01/13 11:51 AM
                                              Mill *is* a speculationanon2019/01/08 08:50 AM
                                                Mill *is* a speculationEric Bron2019/01/08 09:03 AM
                                                  Mill *is* a speculationanon2019/01/08 09:21 AM
                      "Leaf branch" is not a commonly used termMichael S2019/01/03 07:57 AM
                        "Leaf branch" is not a commonly used termBrett2019/01/04 03:29 AM
                  Calls are not needed for speculation for mill if there are no side effect,and dont help if there areHeikki Kultala2019/01/08 04:28 AM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.anon2019/01/02 03:05 AM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Doug S2019/01/02 11:38 AM
                No. Mill does not get the hit because it does not get the benefit even when correctly predicted.rwessel2019/01/02 05:53 PM
                  No. Mill does not get the hit because it does not get the benefit even when correctly predicted.anon2019/01/02 08:56 PM
                    itanicBrett2019/01/03 12:41 AM
                      itanicanon2019/01/03 03:12 AM
                      itanicDavid Hess2019/01/03 08:06 AM
                    No. Mill does not get the hit because it does not get the benefit even when correctly predicted.rwessel2019/01/03 09:18 AM
                      No. Mill does not get the hit because it does not get the benefit even when correctly predicted.anon2019/01/04 05:25 AM
                    Itanium could have been RISC or CISC - same outcomesomeone2019/01/04 07:45 AM
                      Itanium could have been RISC or CISC - same outcomeDoug S2019/01/04 12:39 PM
                        Itanium could have been RISC or CISC - same outcomeJan Olšan2019/01/04 01:58 PM
                          "fluffyRISC" has a namevvid2019/01/04 03:48 PM
                        Itanium could have been RISC or CISC - same outcomeBrett2019/01/04 03:43 PM
                      Itanium could have been RISC or CISC - same outcomeanonymou52019/01/04 12:41 PM
                  No. Mill does not get the hit because it does not get the benefit even when correctly predicted.David Hess2019/01/03 08:15 AM
                No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Maynard Handley2019/01/03 12:24 PM
                  No. Mill does not get the hit because it does not get the benefit even when correctly predicted.Maynard Handley2019/01/03 12:27 PM
                    No. Mill does not get the hit because it does not get the benefit even when correctly predicted.dmcq2019/01/04 01:59 AM
                  EPIC target marketsFoo_2019/01/04 06:29 AM
                    EPIC target marketsDoug S2019/01/04 12:42 PM
                      Lack of future visionDoug S2019/01/04 12:57 PM
                        Lack of future visionBrett2019/01/04 02:59 PM
                          Lack of future visionDoug S2019/01/04 04:25 PM
                            Lack of future visionBrett2019/01/04 05:18 PM
                              Lack of future visionDoug S2019/01/05 12:47 AM
                                Lack of future visionBrett2019/01/05 02:06 PM
                                  Lack of future visiondmcq2019/01/05 02:22 PM
                                  Lack of future visionanon2019/01/05 03:01 PM
                                    Lack of future visionMichael S2019/01/05 04:18 PM
                                      Lack of future visionanon2019/01/05 06:14 PM
                                        Lack of future visionMichael S2019/01/06 02:01 AM
                                          Lack of future visionanon2019/01/06 03:23 AM
                                          Mitch Alsup's MY66000 uses IF-like predication (I think) (NT)Paul A. Clayton2019/01/06 04:54 PM
                                            ??? (NT)Michael S2019/01/07 05:25 AM
                                            88K ? (NT)anonymous22019/01/07 04:20 PM
                                          Modestly expanded response: MY66000 predicate shadowPaul A. Clayton2019/01/07 11:53 AM
                      Thanks for the correction (NT)Foo_2019/01/04 04:31 PM
              No. Mill does not get the hit because it does not get the benefit even when correctly predicted.sdrc2019/01/04 07:36 AM
          Mill and Independent micro threadsMichael S2019/01/02 02:32 AM
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