Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)

By: Maynard Handley (name99.delete@this.name99.org), July 8, 2015 7:23 pm
Room: Moderated Discussions
Sylvain Collange (sylvain.collange.delete.delete@this.this.gmail.com) on July 8, 2015 10:32 am wrote:
> Maynard Handley (name99.delete@this.name99.org) on July 8, 2015 9:46 am wrote:
> > BTW, seeing Andre Seznec's name there, does any commercial
> > processor yet implement a PPM or TAGE-like predictor yet?
>
> I am not aware of any official statement about a commercial TAGE implementation.
>
> But comparing Haswell's performance counters with the output of a TAGE simulator, we observe
> comparable branch misprediction rates on average. (http://hal.inria.fr/hal-01100647/)
>

Inspired by this paper, I looked at the Geekbench3 Lua single core results (which I assume are basically an interpreter, and thus as good a proxy as one can hope for in figuring out this stuff). The results are very interesting.
A8 gets 1787/1.4 =1270 (score/frequency)
Sandy Bridge gets 4269/3.4=1255
Haswell gets 4325/3.3=1310
Nehalem gets 2284/3.2=713
(64-bit for everything except the Nehalem result where I could not find a 64-bit Window result. For some strange reason there are also no Broadwell 64-bit results yet; out of interest the 32-bit result is 2693/2.3=1.17, which perhaps we can take as indicating a 10% penalty for 32-bit mode, giving us some feel for what a 64-bit Nehalem result might be.)

It's merely a hint, not a proof, but it suggests that the intuition is correct (that is it gives the expected big jump in performance for an interpreter from Nehalem to Sandy Bridge). It also suggests that whatever Apple is using for their branch predictor it's pretty impressive. Perhaps not at the TAGE-ITTAGE level of Haswell (especially when we consider that they can make up for a few more branch mispredictions when they can run wider) but a very credible effort, at around the quality of the Sandy Bridge predictors; and presumably headed for something TAGE-like in the near future.

This also suggests (pace Linus' comment that for many purposes the only SPEC result worth paying attention to is the gcc score) that Lua maybe should play that same role for Geekbench?
< Previous Post in ThreadNext Post in Thread >
TopicPosted ByDate
Cyclone Macro-op fusionMaynard Handley2015/07/05 05:01 PM
  Cyclone Macro-op fusionGabriele Svelto2015/07/06 01:11 AM
    Cyclone Macro-op fusionMaynard Handley2015/07/06 09:25 AM
      Cyclone Macro-op fusionWilco2015/07/06 10:17 AM
        Cyclone Macro-op fusionMaynard Handley2015/07/06 11:07 AM
          Cyclone Macro-op fusionMaynard Handley2015/07/06 11:55 AM
            Cyclone Macro-op fusionGabriele Svelto2015/07/07 01:49 AM
      Power8 branch conversionSHK2015/07/06 11:41 AM
        Power8 branch conversionMaynard Handley2015/07/06 12:01 PM
          Power8 branch conversionMaynard Handley2015/07/06 12:09 PM
        Benefit of dynamic hammock predicationPaul A. Clayton2015/07/06 02:02 PM
          Benefit of dynamic hammock predicationMaynard Handley2015/07/06 02:34 PM
            Benefit of dynamic hammock predicationEduardoS2015/07/06 06:56 PM
            Benefit of dynamic hammock predicationPatrick Chase2015/07/06 09:30 PM
          Benefit of dynamic hammock predicationLinus Torvalds2015/07/06 02:59 PM
            Benefit of dynamic hammock predicationWilco2015/07/06 03:35 PM
              Benefit of dynamic hammock predicationLinus Torvalds2015/07/06 04:25 PM
                Benefit of dynamic hammock predicationanon2015/07/06 08:02 PM
            Benefit of dynamic hammock predicationPatrick Chase2015/07/06 09:31 PM
              Benefit of dynamic hammock predicationanon2015/07/06 10:02 PM
              Benefit of dynamic hammock predicationMichael S2015/07/07 12:07 AM
              Benefit of dynamic hammock predicationLinus Torvalds2015/07/07 08:23 AM
                Benefit of dynamic hammock predicationPatrick Chase2015/07/07 09:49 AM
                  Benefit of dynamic hammock predicationSHK2015/07/07 10:34 AM
                  Benefit of dynamic hammock predicationMaynard Handley2015/07/07 11:00 AM
                    Benefit of dynamic hammock predicationExophase2015/07/07 12:26 PM
                      Benefit of dynamic hammock predicationWilco2015/07/07 03:54 PM
                      Benefit of dynamic hammock predicationMaynard Handley2015/07/07 04:25 PM
                    Benefit of dynamic hammock predicationPatrick Chase2015/07/07 01:32 PM
                    Benefit of dynamic hammock predicationMichael S2015/07/08 12:57 AM
                  Benefit of dynamic hammock predicationSylvain Collange2015/07/08 05:30 AM
                    Benefit of dynamic hammock predicationMaynard Handley2015/07/08 08:46 AM
                      Benefit of dynamic hammock predicationSylvain Collange2015/07/08 09:32 AM
                        Benefit of dynamic hammock predicationMaynard Handley2015/07/08 09:57 AM
                        Sadly, skewed associativity has not been broadly adoptedPaul A. Clayton2015/07/08 01:00 PM
                        Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Maynard Handley2015/07/08 07:23 PM
                          Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)David Kanter2015/07/09 06:20 AM
                            Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Maynard Handley2015/07/09 09:04 AM
                              Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Tim McCaffrey2015/07/09 09:41 AM
                                Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Patrick Chase2015/07/09 12:08 PM
                                  Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Sylvain Collange2015/07/10 01:03 AM
                              Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)David Kanter2015/07/09 03:15 PM
                                Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Maynard Handley2015/07/09 04:21 PM
                            Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Patrick Chase2015/07/09 11:44 AM
                          Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)Patrick Chase2015/07/09 08:43 AM
                          Prediction quality of A8 and Intel (was Benefit of dynamic hammock predication)someone2015/07/10 04:43 AM
            Benefit of dynamic hammock predicationKonrad Schwarz2015/07/07 06:54 AM
            Benefit of dynamic hammock predicationdmcq2015/07/07 01:38 PM
              Benefit of dynamic hammock predicationLinus Torvalds2015/07/08 07:23 AM
                Benefit of dynamic hammock predicationdmcq2015/07/08 09:11 AM
                  Benefit of dynamic hammock predicationLinus Torvalds2015/07/08 12:38 PM
                    Example of memory ordering causing excitement in the real worldMark Roulo2015/07/08 03:54 PM
                      Example of memory ordering causing excitement in the real worlddmcq2015/07/09 03:37 AM
                        Example of memory ordering causing excitement in the real worldMark Roulo2015/07/09 07:24 AM
                          Example of memory ordering causing excitement in the real worlddmcq2015/07/09 09:09 AM
                          Example of memory ordering causing excitement in the real worldMaynard Handley2015/07/09 09:12 AM
                            Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/09 11:14 AM
                              Example of memory ordering causing excitement in the real worlddmcq2015/07/09 03:24 PM
                                Example of memory ordering causing excitement in the real worldSimon Farnsworth2015/07/10 12:07 PM
                                  Example of memory ordering causing excitement in the real worlddmcq2015/07/10 02:49 PM
                                    Example of memory ordering causing excitement in the real worldSimon Farnsworth2015/07/12 12:02 PM
                                      Example of memory ordering causing excitement in the real worlddmcq2015/07/13 04:03 AM
                                        Example of memory ordering causing excitement in the real worldMichael S2015/07/13 04:19 AM
                                        Example of memory ordering causing excitement in the real worldSimon Farnsworth2015/07/14 12:21 PM
                                          Example of memory ordering causing excitement in the real worlddmcq2015/07/14 01:54 PM
                                            Example of memory ordering causing excitement in the real worldSimon Farnsworth2015/07/15 12:13 PM
                                              Example of memory ordering causing excitement in the real worlddmcq2015/07/15 02:43 PM
                                                Example of memory ordering causing excitement in the real worldSimon Farnsworth2015/07/16 11:41 AM
                                                  Example of memory ordering causing excitement in the real worldWilco2015/07/17 12:57 PM
                                                    Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/17 03:29 PM
                                                      Example of memory ordering causing excitement in the real worlddmcq2015/07/18 03:07 AM
                                          Example of memory ordering causing excitement in the real worldJouni Osmala2015/07/16 02:52 AM
                                            Example of memory ordering causing excitement in the real worldSimon Farnsworth2015/07/16 12:05 PM
                                              Example of memory ordering causing excitement in the real worldJouni Osmala2015/07/17 12:18 AM
                                                ISA support for bound checkingMichael S2015/07/17 03:51 AM
                                                  ISA support for bound checkingEtienne2015/07/17 05:39 AM
                                                  MPX on SkylakeMark Roulo2015/07/17 07:19 AM
                                                    MPX on SkylakeMichael S2015/07/17 07:44 AM
                                                      MPX on SkylakeMark Roulo2015/07/17 08:03 AM
                                  Example of memory ordering causing excitement in the real worldanon2015/07/12 02:42 AM
                                    Example of memory ordering causing excitement in the real worlddmcq2015/07/12 09:27 AM
                                    Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/12 10:24 AM
                                      Example of memory ordering causing excitement in the real worldEduardoS2015/07/12 10:53 AM
                                        Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/12 12:07 PM
                                          Example of memory ordering causing excitement in the real worldanon2015/07/12 06:52 PM
                                            Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/13 10:05 AM
                                              Example of memory ordering causing excitement in the real worlddmcq2015/07/13 11:20 AM
                                                Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/13 12:46 PM
                                                  Example of memory ordering causing excitement in the real worldMaynard Handley2015/07/13 01:10 PM
                                                    Example of memory ordering causing excitement in the real worldanon2015/07/13 07:51 PM
                                                    Simple cores justifying weak ordering?Paul A. Clayton2015/07/14 08:01 AM
                                                      David's Paul A. Clayton2015/07/14 08:37 AM
                                                      David's 2015-07-12 10:34 post confirmed some of that (NT)Paul A. Clayton2015/07/14 08:39 AM
                                                    Example of memory ordering causing excitement in the real worldEtienne2015/07/17 12:15 AM
                                                  Example of memory ordering causing excitement in the real worlddmcq2015/07/13 01:14 PM
                                                  Reality is even worseTerry Gray2015/07/13 05:05 PM
                                                    Reality is even worseKonrad Schwarz2015/07/20 11:13 PM
                                                  A simple CAS/MCAS semantics2015/07/15 11:54 AM
                                                    A simple CAS/MCAS semanticsLinus Torvalds2015/07/15 12:55 PM
                                                    A simple CAS/MCAS semanticsEduardoS2015/07/15 01:31 PM
                                                Example of memory ordering causing excitement in the real worldsylt2015/07/13 01:19 PM
                                                  Example of memory ordering causing excitement in the real worlddmcq2015/07/13 02:24 PM
                                                    Example of memory ordering causing excitement in the real worldEduardoS2015/07/13 03:48 PM
                                                      Example of memory ordering causing excitement in the real worldMaynard Handley2015/07/13 06:18 PM
                                                        Example of memory ordering causing excitement in the real worldEduardoS2015/07/13 06:57 PM
                                                      Example of memory ordering causing excitement in the real worldanon2015/07/13 08:01 PM
                                                    What high level languages do you have in mind?Mark Roulo2015/07/13 04:00 PM
                                                      What high level languages do you have in mind?dmcq2015/07/14 05:54 AM
                                                  Example of memory ordering causing excitement in the real worldWilco2015/07/13 03:36 PM
                                                    Example of memory ordering causing excitement in the real worldEduardoS2015/07/13 03:56 PM
                                                      Example of memory ordering causing excitement in the real worldanon2015/07/13 05:43 PM
                                                        Example of memory ordering causing excitement in the real worldEduardoS2015/07/13 07:11 PM
                                                          Example of memory ordering causing excitement in the real worldanon2015/07/13 08:07 PM
                                      Example of memory ordering causing excitement in the real worldMaynard Handley2015/07/12 11:32 AM
                                        Example of memory ordering causing excitement in the real worldEduardoS2015/07/12 12:35 PM
                                        Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/12 12:38 PM
                                          Example of memory ordering causing excitement in the real worldEduardoS2015/07/12 05:47 PM
                                            Example of memory ordering causing excitement in the real worldNoSpammer2015/07/13 11:34 AM
                                              Example of memory ordering causing excitement in the real worldWilco2015/07/13 03:50 PM
                                                Example of memory ordering causing excitement in the real worldNoSpammer2015/07/14 01:02 PM
                                                  Example of memory ordering causing excitement in the real worldanon2015/07/14 08:37 PM
                                                    Example of memory ordering causing excitement in the real worldMichael S2015/07/15 12:19 AM
                                                      Example of memory ordering causing excitement in the real worldanon2015/07/15 01:26 AM
                                                        Example of memory ordering causing excitement in the real worldNoSpammer2015/07/15 06:05 AM
                                                          Example of memory ordering causing excitement in the real worlddmcq2015/07/15 07:04 AM
                                                            Example of memory ordering causing excitement in the real worldMichael S2015/07/15 07:29 AM
                                                              Example of memory ordering causing excitement in the real worlddmcq2015/07/15 09:09 AM
                                                              Can string ops use microarchitectural state?Paul A. Clayton2015/07/16 08:33 AM
                                                                Can string ops use microarchitectural state?rwessel2015/07/16 12:00 PM
                                                                  Can string ops use microarchitectural state?Paul A. Clayton2015/07/16 05:16 PM
                                                                    Can string ops use microarchitectural state?rwessel2015/07/16 08:34 PM
                                                                      Can string ops use microarchitectural state?Michael S2015/07/17 04:39 AM
                                                                        Can string ops use microarchitectural state?rwessel2015/07/17 08:02 AM
                                                                Consider interrupt followed by task preemptionMichael S2015/07/16 03:31 PM
                                                                  Consider interrupt followed by task preemptionPaul A. Clayton2015/07/16 05:23 PM
                                                            Example of memory ordering causing excitement in the real worldNoSpammer2015/07/15 11:50 AM
                                                              Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/15 01:27 PM
                                                                Example of memory ordering causing excitement in the real worldNoSpammer2015/07/15 02:14 PM
                                                                  Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/15 04:42 PM
                                                      Example of memory ordering causing excitement in the real worldNoSpammer2015/07/15 01:44 AM
                                                    Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/15 01:17 PM
                                                      Example of memory ordering causing excitement in the real worldWilco2015/07/15 01:43 PM
                                                        Example of memory ordering causing excitement in the real worldanon2015/07/15 04:45 PM
                                                        Example of memory ordering causing excitement in the real worldLinus Torvalds2015/07/15 05:35 PM
                                                          Example of memory ordering causing excitement in the real worlddmcq2015/07/16 01:46 AM
                                                            Example of memory ordering causing excitement in the real worlddmcq2015/07/16 01:49 AM
                                        Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/21 06:15 AM
                                      Example of memory ordering causing excitement in the real worldanon2015/07/12 06:42 PM
                                        Example of memory ordering causing excitement in the real worldanon2015/07/12 08:48 PM
                                        Example of memory ordering causing excitement in the real worldDavid Kanter2015/07/12 09:34 PM
                                          Example of memory ordering causing excitement in the real worldMichael S2015/07/13 12:51 AM
                                            Example of memory ordering causing excitement in the real worldDavid Kanter2015/07/13 07:31 AM
                                          Example of memory ordering causing excitement in the real worldanon2015/07/13 05:05 AM
                                            Example of memory ordering causing excitement in the real worldGabriele Svelto2015/07/17 04:40 AM
                                          Example of memory ordering causing excitement in the real worlddmcq2015/07/13 07:09 AM
                                        Example of memory ordering causing excitement in the real worldanon2015/07/13 06:46 AM
                                          Example of memory ordering causing excitement in the real worldanon2015/07/14 03:12 AM
                                        Example of memory ordering causing excitement in the real worlddmcq2015/07/15 02:51 AM
                                          Example of memory ordering causing excitement in the real worldanon2015/07/15 03:38 AM
                                            Example of memory ordering causing excitement in the real worlddmcq2015/07/15 05:21 AM
                                      Store queues in POWER/PowerPC processorsGabriele Svelto2015/07/16 12:55 AM
                                        Not sure about that conclusionDavid Kanter2015/07/16 06:34 AM
                                          The POWER4 had the same structureGabriele Svelto2015/07/17 04:20 AM
                                        Committing stores in program orderPaul A. Clayton2015/07/16 12:35 PM
                                          Committing stores in program orderMaynard Handley2015/07/17 11:52 AM
                                      Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/20 03:44 AM
                                        Example of memory ordering causing excitement in the real worldanon2015/07/20 06:29 AM
                                          Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/20 11:08 PM
                                            Example of memory ordering causing excitement in the real worlddmcq2015/07/21 12:27 AM
                                            Example of memory ordering causing excitement in the real worldMichael S2015/07/21 02:11 AM
                                              Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/21 04:24 AM
                                            Example of memory ordering causing excitement in the real worldanon2015/07/21 05:22 AM
                                              Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/21 06:36 AM
                                                Example of memory ordering causing excitement in the real worldanon2015/07/21 07:25 AM
                                              Example of memory ordering causing excitement in the real worldanon2015/07/21 07:17 AM
                                                Example of memory ordering causing excitement in the real worldanon2015/07/21 08:50 AM
                                                Example of memory ordering causing excitement in the real worldGabriele Svelto2015/07/21 11:46 AM
                                                Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/21 11:35 PM
                                                  Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/22 12:37 AM
                                                  Example of memory ordering causing excitement in the real worldanon2015/07/23 02:17 AM
                                                    Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/23 03:59 AM
                                                      Example of memory ordering causing excitement in the real worldMichael S2015/07/23 06:31 AM
                                                        Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/23 02:38 PM
                                                          Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/23 10:44 PM
                                                            Example of memory ordering causing excitement in the real worlddmcq2015/07/24 12:08 AM
                                    Example of memory ordering causing excitement in the real worlddmcq2015/07/13 06:27 AM
                          Example of memory ordering causing excitement in the real worldKonrad Schwarz2015/07/16 04:11 AM
                      Example of memory ordering causing excitement in the real worldAnonymousse2015/07/16 04:07 AM
          Benefit of dynamic hammock predicationsomeotherdude2015/07/06 04:12 PM
            Benefit of dynamic hammock predicationMichael S2015/07/07 12:19 AM
          Benefit of dynamic hammock predicationPatrick Chase2015/07/06 09:20 PM
            SIMD predication is also helpful, of course (NT)Paul A. Clayton2015/07/07 06:45 AM
        Power8 branch conversionGabriele Svelto2015/07/07 01:50 AM
          isel works for storesPaul A. Clayton2015/07/07 06:43 AM
            isel works for storesPatrick Chase2015/07/07 10:08 AM
            isel DOES NOT work for storessomeotherdude2015/07/07 03:01 PM
              isel DOES NOT work for storesWilco2015/07/07 03:40 PM
              Yes it doesPatrick Chase2015/07/07 10:14 PM
                Yes it doesvvid2015/07/08 08:51 AM
            You don't need isel eitherGabriele Svelto2015/07/08 01:01 AM
              You don't need isel eitherPaul A. Clayton2015/07/08 03:46 AM
                You don't need isel eitherGabriele Svelto2015/07/08 04:22 AM
Reply to this Topic
Name:
Email:
Topic:
Body: No Text
How do you spell green?