Avoiding ping pong

By: Jouni Osmala (josmala.delete@this.cc.hut.fi), December 8, 2014 3:47 pm
Room: Moderated Discussions
> > I'm assuming that 90+% of programs already run fast enough and they don't matter for this.
> > Its all about asking question in what use current computers are too slow , and can you parallerize
> > that or are those cases already parallel. And I'm assuming you can parallerize atleast 10%
> > of those times where user waits CPU for long enough to actually notice it.
>
> What's the advantage?
>
> You won't get scaling for much longer, and current trends are actually for lower power anyway. So what's the
> upside of pushing the whole parallelism snake-oil? We know that we need fairly complex OoO CPU's anyway, because
> people want reasonable performance and it turns out OoO is actually more efficient than slow in-order.

There is enough scaling left to turn somewhat better than current high end xeons to client CPU:s . Especially when stacked dram becomes standard and L3 cache becomes redundant due to lower latency on main memory, and there would be enormous bandwidth available to CPU:s.

> The whole "let's parallelize" thing is a huge waste of everybody's time. There's this huge
> body of "knowledge" that parallel is somehow more efficient, and that whole huge body is pure
> and utter garbage. Big caches are efficient. Parallel stupid small cores without caches are
> horrible unless you have a very specific load that is hugely regular (ie graphics).

On arm front highly parallel world may become reality, on Intel world its more like having 16 core client where each core is slightly MORE powerful than current core , and servers probably have 60 of same cores but having lower base frequency and higher power budget.

> Nobody is ever going to go backwards from where we are today. Those complex OoO cores aren't going away.

I'm talking about diminishing return's on going beyond where those complex OoO cores are right now. And there is enough scaling left to go for 16+ cores of similar complexity of current high end cores with added wider vector unit.

> Where the hell do you envision that those magical parallel algorithms would be used?
>
> The only place where parallelism matters is in graphics or on the server side,
> where we already largely have it. Pushing it anywhere else is just pointless.

I'm considering compiling large programs with multiple files, running large excel simulations, laying out large documents with multiple chapters, designing buildings and zoning, machine engineering... Its where employees spend their time waiting computer to finish calculating something, or hobbyist doing same things.

> So give up on parallelism already. It's not going to happen. End users are fine with roughly
> on the order of four cores, and you can't fit any more anyway without using too much energy
> to be practical in that space. And nobody sane would make the cores smaller and weaker in order
> to fit more of them - the only reason to make them smaller and weaker is because you want to
> go even further down in power use, so you'd still not have lots of those weak cores.

My point was you cannot really do much more powerful x86 core , and if you want more performance the parallerism is only direction to go, and scaling trends give us enough to go for 16 cores on client.
< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
ARMv8 getting atomic operationsdmcq2014/12/02 05:32 PM
  ARMv8 getting atomic operationsMaynard Handley2014/12/02 07:33 PM
    ARMv8 getting atomic operationsDoug S2014/12/02 10:30 PM
      ARMv8 getting atomic operationsdmcq2014/12/03 03:16 AM
      ARMv8 getting atomic operationsMaynard Handley2014/12/03 09:20 AM
      ARMv8 getting atomic operationsBrett2014/12/03 04:46 PM
    ARMv8 getting atomic operationsAndreas2014/12/03 06:51 AM
      ARMv8 getting atomic operationsLinus Torvalds2014/12/03 11:15 AM
        ARMv8 getting atomic operationsanon2014/12/03 05:08 PM
          Guaranteed transactionsPaul A. Clayton2014/12/03 08:04 PM
            Guaranteed transactionsanon2014/12/03 08:38 PM
              Avoiding ping pongPaul A. Clayton2014/12/04 09:11 AM
                Avoiding ping ponganon2014/12/04 10:15 AM
                  OoO window is limitedPaul A. Clayton2014/12/04 01:06 PM
                Avoiding ping pongAaron Spink2014/12/04 12:01 PM
                  Avoiding ping pongKonrad Schwarz2014/12/04 01:10 PM
                    Avoiding ping pongAaron Spink2014/12/04 02:31 PM
                    Avoiding ping pongGabriele Svelto2014/12/04 02:49 PM
                      Avoiding ping pongKonrad Schwarz2014/12/04 11:08 PM
                        Avoiding ping pongGabriele Svelto2014/12/05 12:04 AM
                          Avoiding ping pongEric Bron nli2014/12/05 02:28 AM
                            Avoiding ping pongKonrad Schwarz2014/12/05 03:37 AM
                              Avoiding ping pongEric Bron nli2014/12/05 04:23 AM
                                Avoiding ping pongKlimax2014/12/05 05:47 AM
                                  Avoiding ping pongEric Bron2014/12/05 06:24 AM
                              Avoiding ping pongGabriele Svelto2014/12/05 10:38 AM
                                Avoiding ping pongKonrad Schwarz2014/12/07 02:28 PM
                                  Avoiding ping pongGabriele Svelto2014/12/08 07:10 PM
                                    Avoiding ping pongKonrad Schwarz2014/12/09 05:12 AM
                                      Avoiding ping pongGabriele Svelto2014/12/09 07:31 AM
                                        Avoiding ping ponganon2014/12/09 11:24 PM
                            Avoiding ping pongGabriele Svelto2014/12/05 10:17 AM
                              Avoiding ping pongEric Bron2014/12/05 10:32 AM
                                Avoiding ping pongGabriele Svelto2014/12/05 12:45 PM
                                  Avoiding ping pongEric Bron2014/12/06 02:20 AM
                                    Avoiding ping pongnksingh2014/12/06 03:42 AM
                                      Avoiding ping pongEric Bron2014/12/06 04:04 AM
                                        Avoiding ping pongGiGNiC2014/12/06 06:27 AM
                                          Avoiding ping pongEric Bron nli2014/12/06 06:44 AM
                                          Avoiding ping pongEric Bron2014/12/06 07:07 AM
                                            Avoiding ping pongnksingh2014/12/07 04:06 PM
                                              Avoiding ping pongEric Bron2014/12/08 04:17 AM
                                                Avoiding ping pongGiGNiC2014/12/08 11:53 AM
                                                Avoiding ping pongnksingh2014/12/08 05:53 PM
                                                  Avoiding ping pongEric Bron2014/12/09 01:33 AM
                                    Avoiding ping pongdmsc2014/12/06 04:12 AM
                                      Avoiding ping pongEric Bron2014/12/06 04:25 AM
                                        Avoiding ping pongKlimax2014/12/06 05:49 AM
                                          Avoiding ping pongrwessel2014/12/07 02:34 AM
                                        Avoiding ping pongdmsc2014/12/06 07:39 AM
                                        Avoiding ping pongKonrad Schwarz2014/12/07 02:37 PM
                                          Avoiding ping pongMichael S2014/12/07 04:37 PM
                                            Avoiding ping pongKonrad Schwarz2014/12/08 04:35 AM
                          Avoiding ping pongKonrad Schwarz2014/12/05 03:30 AM
                        Avoiding ping pongLinus Torvalds2014/12/05 12:58 PM
                          Avoiding ping pongEric Bron2014/12/06 02:42 AM
                            Avoiding ping pongnksingh2014/12/06 03:51 AM
                              Avoiding ping pongEric Bron2014/12/06 04:08 AM
                            Avoiding ping pongLinus Torvalds2014/12/06 01:25 PM
                              Avoiding ping pongnksingh2014/12/07 03:26 PM
                                Avoiding ping pongEric Bron2014/12/08 04:35 AM
                                  Avoiding ping pongBrett2014/12/08 10:00 AM
                                    Avoiding ping pongEric Bron2014/12/08 10:48 AM
                                    Avoiding ping pongrwessel2014/12/08 12:52 PM
                                      Avoiding ping pongBrett2014/12/08 01:58 PM
                                      Avoiding ping pongDoug S2014/12/08 02:04 PM
                              Avoiding ping pongJouni Osmala2014/12/08 02:45 AM
                                Avoiding ping ponganon2014/12/08 05:44 AM
                                  Avoiding ping pongJouni Osmala2014/12/08 01:10 PM
                                    Avoiding ping pongLinus Torvalds2014/12/08 01:34 PM
                                      Avoiding ping pongJouni Osmala2014/12/08 03:47 PM
                                        Avoiding ping pongLinus Torvalds2014/12/08 08:08 PM
                                          Avoiding ping pongGabriele Svelto2014/12/09 07:48 AM
                                            Avoiding ping pongMaynard Handley2014/12/09 11:41 AM
                                              Avoiding ping pongPatrick Chase2014/12/09 01:06 PM
                                              Avoiding ping pongGabriele Svelto2014/12/09 01:52 PM
                                                Avoiding ping pongPatrick Chase2014/12/09 02:08 PM
                                            Why read RWT or Reddit when you can get journalists to do it for you?Rob Thorpe2015/01/02 08:20 AM
                                              Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/02 11:21 AM
                                                Why read RWT or Reddit when you can get journalists to do it for you?EduardoS2015/01/02 11:37 AM
                                                  Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/03 12:00 PM
                                                Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron nli2015/01/02 02:28 PM
                                                  Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/03 12:02 PM
                                                    Why read RWT or Reddit when you can get journalists to do it for you?Michael S2015/01/03 12:36 PM
                                                      Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/03 01:11 PM
                                                        Why read RWT or Reddit when you can get journalists to do it for you?Michael S2015/01/03 01:30 PM
                                                          Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron2015/01/03 02:57 PM
                                                            KNL cacheDavid Kanter2015/01/03 07:36 PM
                                                              KNL cacheEric Bron2015/01/04 03:34 AM
                                                                KNL cacheMichael S2015/01/04 04:11 AM
                                                                  KNL cacheEric Bron2015/01/04 04:57 AM
                                                                    KNL cacheMichael S2015/01/04 05:21 AM
                                                                      KNL cacheEric Bron2015/01/04 05:58 AM
                                                          Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/07 05:47 AM
                                                            Why read RWT or Reddit when you can get journalists to do it for you?Michael S2015/01/07 08:27 AM
                                                              Manycores vs multicoresjuanrga2015/01/10 04:10 PM
                                                                Manycores vs multicoresAaron Spink2015/01/10 05:32 PM
                                                                  Manycores vs multicoresjuanrga2015/01/10 06:32 PM
                                                                    Manycores vs multicoresExophase2015/01/10 06:49 PM
                                                                      Manycores vs multicoresjuanrga2015/01/10 08:21 PM
                                                                        Manycores vs multicoresExophase2015/01/10 08:51 PM
                                                                        Manycores vs multicoresAaron Spink2015/01/10 09:03 PM
                                                                    Manycores vs multicoresAaron Spink2015/01/10 07:21 PM
                                                                      Manycores vs multicoresjuanrga2015/01/10 08:25 PM
                                                                        Manycores vs multicoresAaron Spink2015/01/10 09:11 PM
                                                                          Manycores vs multicoresJouni Osmala2015/01/11 04:50 AM
                                                                            Manycores vs multicoresjuanrga2015/01/11 08:58 AM
                                                                            Manycores vs multicorescoppice2015/01/12 10:01 PM
                                                                              Manycores vs multicoresJouni Osmala2015/01/13 04:38 AM
                                                                        Manycores vs multicoresanon2015/01/11 03:19 AM
                                                                      Manycores vs multicoresMichael S2015/01/11 05:44 AM
                                                                        Manycores vs multicoresAaron Spink2015/01/11 05:55 PM
                                                                          Manycores vs multicoresMichael S2015/01/12 04:41 AM
                                                                            Manycores vs multicoresEric Bron2015/01/12 06:29 AM
                                                                              Manycores vs multicoresEric Bron2015/01/12 06:30 AM
                                                        Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron2015/01/03 02:54 PM
                                                          Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/07 05:48 AM
                                                            Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron2015/01/07 07:41 AM
                                                              Manycores vs multicoresjuanrga2015/01/10 04:14 PM
                                                    Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron2015/01/03 02:42 PM
                                                      Why read RWT or Reddit when you can get journalists to do it for you?juanrga2015/01/07 06:03 AM
                                                        Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron2015/01/07 07:45 AM
                                                        Why read RWT or Reddit when you can get journalists to do it for you?Linus Torvalds2015/01/08 03:09 PM
                                                          Pink unicorns for salejuanrga2015/01/10 05:09 PM
                                                        Intentionally picking a competitors slow part is cheating ...Mark Roulo2015/01/08 06:37 PM
                                                          Intentionally picking a competitors slow part is cheating ...coppice2015/01/08 11:38 PM
                                                            Intentionally picking a competitors slow part is cheating ...Mark Roulo2015/01/09 09:13 AM
                                                              Intentionally picking a competitors slow part is cheating ...Anon2015/01/10 02:00 AM
                                                              Intentionally picking a competitors slow part is cheating ...David Hess2015/01/11 01:03 PM
                                                            Intentionally picking a competitors slow part is cheating ...someone2015/01/09 10:31 AM
                                                              Intentionally picking a competitors slow part is cheating ...coppice2015/01/12 09:45 PM
                                                                Intentionally picking a competitors slow part is cheating ...coppice2015/01/12 09:47 PM
                                                                  Intentionally picking a competitors slow part is cheating ...Michael S2015/01/13 07:53 AM
                                                                    Intentionally picking a competitors slow part is cheating ...coppice2015/01/13 09:44 AM
                                                                      Intentionally picking a competitors slow part is cheating ...Michael S2015/01/13 10:01 AM
                                                                        Intentionally picking a competitors slow part is cheating ...coppice2015/01/13 08:35 PM
                                                                      Core sizesjuanrga2015/01/13 12:28 PM
                                                          NVIDIA'S FIRST CPU IS A WINNER (Linley Gwennap)juanrga2015/01/10 04:34 PM
                                                        Why read RWT or Reddit when you can get journalists to do it for you?Patrick Chase2015/01/08 07:02 PM
                                                        Why read RWT or Reddit when you can get journalists to do it for you?coppice2015/01/08 10:18 PM
                                                          Why read RWT or Reddit when you can get journalists to do it for you?Patrick Chase2015/01/09 11:54 AM
                                                            Why read RWT or Reddit when you can get journalists to do it for you?Mark Roulo2015/01/09 12:59 PM
                                                              Why read RWT or Reddit when you can get journalists to do it for you?Patrick Chase2015/01/09 03:20 PM
                                                                Why read RWT or Reddit when you can get journalists to do it for you?Eric Bron2015/01/09 03:30 PM
                                                            Alternatives to OOOE (again)juanrga2015/01/10 04:50 PM
                                                              Alternatives to OOOE (again)David Kanter2015/01/11 12:10 AM
                                                                Alternatives to OOOE (again)juanrga2015/01/11 08:30 AM
                                                            Why read RWT or Reddit when you can get journalists to do it for you?Gabriele Svelto2015/01/11 12:53 AM
                                              Why read RWT or Reddit when you can get journalists to do it for you?Fake Linus Torvalds2015/01/03 12:14 PM
                                                Why read RWT or Reddit when you can get journalists to do it for you?Rob Thorpe2015/01/03 08:25 PM
                                          Avoiding ping pongMaynard Handley2014/12/09 11:33 AM
                                            Avoiding ping pongPatrick Chase2014/12/09 01:54 PM
                                              Avoiding ping pongMaynard Handley2014/12/09 06:56 PM
                                      Avoiding ping pongSalvatore De Dominicis2014/12/09 08:51 AM
                                        Avoiding ping pongPatrick Chase2014/12/09 02:00 PM
                                      Avoiding ping pongook2014/12/11 03:31 AM
                                      Avoiding ping pongArt Scott2014/12/19 10:19 PM
                                        Avoiding ping pongEric Bron nli2014/12/20 04:05 AM
                                      What about specialization?Troll?2015/01/02 07:55 AM
                                        What about specialization?Ungo2015/01/04 03:27 PM
                                      Avoiding ping pongfewwef2015/01/05 08:16 PM
                                      Avoiding ping pongV.Krishn2015/01/08 06:11 AM
                                    Avoiding ping pongGabriele Svelto2014/12/08 07:32 PM
                                    Avoiding ping ponganon2014/12/08 11:37 PM
                            Avoiding ping pongKonrad Schwarz2014/12/10 06:23 AM
                              Avoiding ping pongLinus Torvalds2014/12/10 11:56 AM
                          Object reference lockingDavid W2014/12/08 11:36 PM
                            Object reference lockingPatrick Chase2014/12/09 04:52 PM
                              Object reference lockingDavid W2014/12/11 05:18 AM
                    ISA != interface for "most programmers"Paul A. Clayton2014/12/04 03:34 PM
                      ISA != interface for "most programmers"rwessel2014/12/04 07:50 PM
                  Interesting! (exporting hot lines/cache-aware ISA); "Please sir, I want some more" (NT)Paul A. Clayton2014/12/04 02:26 PM
                  Avoiding ping pongMichael S2014/12/06 03:48 PM
          ARMv8 getting atomic operationsLinus Torvalds2014/12/04 12:05 PM
            LL/SC idiom recognition is not admitting RMW superiorityPaul A. Clayton2014/12/04 02:34 PM
            ARMv8 getting atomic operationsanon2014/12/04 10:17 PM
    ARMv8 getting atomic operationsPatrick Chase2014/12/03 12:09 PM
  limited ordernksingh2014/12/04 10:17 PM
    I didn't understand this either. (NT)Konrad Schwarz2014/12/04 10:32 PM
    limited orderdmcq2014/12/05 02:13 AM
    limited orderbakaneko2014/12/05 09:11 AM
Reply to this Topic
Name:
Email:
Topic:
Body: No Text
How do you spell green?