Rome / Zen 2 Deepdive

By: Beastian (no.email.delete@this.aol.com), August 15, 2019 2:26 pm
Room: Moderated Discussions
Perhaps a sneak-peek of the Hotchips presentation? (Apologies if this has already been posted...)

https://www.nextplatform.com/2019/08/15/a-deep-dive-into-amds-rome-epyc-architecture/

The 7nm process and chiplets enable gobs of extra cache and many more cores. Allocating more die area to the uop cache from upstream L1 seems like a key performance / power efficiency tweak:

... One the big ways this was accomplished was by doubling the op cache in the core, which helped save power and also increased performance.

In fact, AMD actually shrank the L1 instruction cache on each Zen 2 core, from 64 KB back to 32 KB, and gave that transistor area back to the op and branch prediction units and also used some of it to add a third address generation unit. The associativity of the L1 data and instruction caches (both at 32 KB) was doubled to eight-way, and AMD doubled the floating point data path width and then doubled up the L1 cache bandwidth to keep up with it. (Clark said that an eight-way associative L1 cache at 64 KB was going to eat far too much power, and with 64 cores, that was going to be a big problem.) The L3 cache was doubled up on each chiplet to 16 MB a pop, and with twice as many chiplets on the package that is four times the L3 cache capacity, at 256 MB, as what was in the Naples processor.


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TopicPosted ByDate
Rome / Zen 2 DeepdiveBeastian2019/08/15 02:26 PM
  Rome / Zen 2 DeepdiveAlberto2019/08/16 09:30 AM
    Rome / Zen 2 DeepdiveAdrian2019/08/16 10:10 AM
    Rome / Zen 2 Deepdiveblue2019/08/16 10:14 AM
      clarifyblue2019/08/16 10:16 AM
        clarifyanon2019/08/16 11:15 AM
          clarifyAdrian2019/08/16 11:51 AM
            clarifyanon2019/08/16 01:44 PM
              clarifyMichael S2019/08/17 02:23 PM
                clarifyAdrian2019/08/17 10:14 PM
                clarifyanon2019/08/18 01:58 AM
                  clarifyJukka Larja2019/08/18 02:23 AM
                    clarifyanon2019/08/18 11:06 AM
          clarifyblue2019/08/16 11:12 PM
        Rome ST performanceAdrian2019/08/30 01:10 PM
          Rome ST performance. Not so goodAlberto2019/08/31 02:22 AM
            keep on trolling Albertoblue2019/08/31 02:30 AM
              keep on trolling AlbertoAlberto2019/09/02 09:50 AM
                keep on trolling Albertoblue2019/09/02 09:47 PM
                  keep on trolling AlbertoAlberto2019/09/03 03:31 AM
                    keep on trolling Albertoblue2019/09/03 10:29 PM
                      Alberto, taped in and taped outJames2019/09/04 03:30 AM
                        Alberto, taped in and taped outAnon2019/09/04 10:08 PM
                          Alberto, taped in and taped outblue2019/09/04 10:31 PM
                            tape in kind of alpha tape outEric Bron2019/09/05 07:32 AM
                              tape in kind of alpha tape outJG2019/09/05 09:53 AM
                                tape in kind of alpha tape outanon2019/09/05 10:37 AM
                                  tape in kind of alpha tape outDoug S2019/09/05 12:45 PM
                    "taped in" means what, exactly? (NT)Random Engineer2019/09/07 07:07 AM
                      "taped in" means what, exactly?Adrian2019/09/07 07:33 AM
            Rome ST performance. Not so goodWilco2019/08/31 05:25 AM
              Rome ST performance. Not so goodjuanrga2019/09/01 06:36 AM
                Rome ST performance. Not so goodAdrian2019/09/01 07:27 AM
                  Rome ST performance. Not so goodjuanrga2019/09/01 10:38 PM
                    AVXblue2019/09/02 09:21 AM
                      AVXanon2019/09/02 10:10 AM
                      AVXjuanrga2019/09/14 04:25 AM
                Rome ST performance. Not so goodanon2019/09/01 07:29 AM
              Rome ST performance. Not so goodAlberto2019/09/02 10:16 AM
                Rome ST performance. Not so goodWilco2019/09/02 03:17 PM
                  Rome ST performance. Not so goodnone2019/09/03 01:17 AM
                    Rome ST performance. Not so goodLinus Torvalds2019/09/03 09:58 AM
                      you are correct on Zen2 L3 size (NT)blue2019/09/03 10:09 AM
                        Almost correct on L3 sizeanon2019/09/04 05:43 AM
                      Makes a lot of sense. Thanks (NT)none2019/09/03 10:22 AM
                      Rome ST performance. Not so goodLinus Torvalds2019/09/03 10:24 AM
                        Rome ST performance. Not so goodanon.12019/09/04 07:08 AM
                          Rome ST performance. Not so goodMichael S2019/09/04 07:19 AM
                            Rome ST performance. Not so goodanon.12019/09/04 07:21 AM
                      Rome ST performance. Not so goodGabriele Svelto2019/09/03 12:08 PM
                      Rome ST performance. Not so goodMichael S2019/09/03 01:29 PM
            Typical lies from a shillnobody in particular2019/08/31 05:53 AM
              Typical lies from a shill...this remember me old days :)Alberto2019/09/02 10:45 AM
          Rome ST performanceFoo_2019/08/31 04:31 AM
            Rome ST performanceWilco2019/08/31 05:17 AM
              Rome ST performanceFoo_2019/08/31 06:35 AM
                Rome ST performanceWilco2019/08/31 06:56 AM
              Rome ST performanceMichael S2019/08/31 12:43 PM
                Xeon EAdrian2019/09/01 12:37 AM
                  Xeon EDavid Hess2019/09/01 12:15 PM
                    Xeon EAdrian2019/09/01 11:10 PM
                      Xeon EDavid Hess2019/09/02 04:15 AM
                        hand waving (NT)Michael S2019/09/02 06:03 AM
            Rome ST performanceAdrian2019/08/31 05:40 AM
              Rome ST performanceFoo_2019/08/31 06:39 AM
              Rome ST performanceanon.12019/08/31 08:27 PM
                Rome ST performanceGionatan Danti2019/09/01 08:51 AM
                  Rome ST performanceGroo2019/09/01 09:31 AM
                    Rome ST performanceJukka Larja2019/09/01 10:54 AM
                      Rome ST performanceGionatan Danti2019/09/01 11:24 AM
                    Rome ST performanceGionatan Danti2019/09/01 11:07 AM
          Rome ST performanceLinus Torvalds2019/08/31 11:13 AM
            Rome ST performanceGabriele Svelto2019/09/01 07:18 AM
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