Ryzen 9 5000 series processor

By: rwessel (rwessel.delete@this.yahoo.com), January 7, 2021 6:47 pm
Room: Moderated Discussions
Jörn Engel (joern.delete@this.purestorage.com) on January 7, 2021 4:29 pm wrote:
> rwessel (rwessel.delete@this.yahoo.com) on January 7, 2021 9:25 am wrote:
> >
> > So SECDEC on a 32-bit word requires seven bits, eight bits on a 64-bit word, nine bits on a 128-bit word.
> > Doing that on 64-bit words has the advantage of allowing fairly simple 8x9 or 9x8 RAM configurations.
>
> If the memory interface is 64bit, but the cacheline size is 64 _Bytes_, you need to do 8 reads anyway.
> I wonder how hard it would be to do 9 reads to get the extra ECC information. That would simplify
> things quite a bit, you can use the same DIMMs and motherboards. You can also get away with relatively
> fewer bits for ECC, so it might be possible to reduce overhead from 12.5% to something closer to
> 2.15%. Memory bandwidth is reduced by 11%, which would be fine in my book.
>
> Any CPU manufacturer should be able to do something like that. And I believe I can find old
> implementations of that going back close to 20 years. So why isn't it done all the time?


There was a discussion here of "in band" ECC, which does about what you're describing.

https://www.realworldtech.com/forum/?threadid=198228&curpostid=198228

A problem with your approach is the non-linear addressing of physical memory (although it's not that bad, a shift and add in the addressing path). The overhead is a bigger issue. Doing nine physical memory words for eight addressable words doesn't reduce the overhead, although a more complex scheme might. Crossing DRAM boundaries array is going to be a hit as well, a non-trivial number of 64-byte cache line reads are going to now cross some sort of boundary that will end up needing two separate read operations.

A bigger problem is that you now can't even do the ECC check before reading all nine words. So any optimized cache line loads (critical word first, etc.), become impossible.

Of course those are all performance issues, and may be a suitable tradeoff in some cases.
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TopicPosted ByDate
Ryzen 9 5000 series processor Phil9955112020/12/29 05:12 AM
  Ryzen 9 5000 series processor Adrian2020/12/29 07:31 AM
    Ryzen 9 5000 series processor Dummond D. Slow2020/12/29 10:33 AM
      Ryzen 9 5000 series processor Phil9955112020/12/29 04:09 PM
        Ryzen 9 5000 series processor Dummond D. Slow2020/12/29 06:00 PM
          Ryzen 9 5000 series processor anon2020/12/30 02:50 AM
          Ryzen 9 5000 series processor Foo_2020/12/30 02:50 AM
            Ryzen 9 5000 series processor Phil9955112020/12/30 05:22 AM
              Ryzen 9 5000 series processor Phil9955112020/12/30 05:25 AM
              Ryzen 9 5000 series processor Adrian2020/12/30 06:00 AM
            Ryzen 9 5000 series processor Linus Torvalds2020/12/30 12:00 PM
              Ryzen 9 5000 series processor Phil9955112020/12/31 06:45 AM
                Ryzen 9 5000 series processor Adrian2020/12/31 09:49 AM
                Ryzen 9 5000 series processor Linus Torvalds2020/12/31 12:05 PM
                  Ryzen 9 5000 series processor me2020/12/31 04:56 PM
                    Ryzen 9 5000 series processor Anon2020/12/31 05:48 PM
                      Ryzen 9 5000 series processor me2021/01/01 04:06 AM
                    Ryzen 9 5000 series processor Gabriele Svelto2021/01/01 07:10 AM
                      Ryzen 9 5000 series processor David Hess2021/01/01 07:37 AM
                        Ryzen 9 5000 series processor Jukka Larja2021/01/01 10:52 AM
                          Ryzen 9 5000 series processor Linus Torvalds2021/01/01 12:48 PM
                            Ryzen 9 5000 series processor Jukka Larja2021/01/01 10:28 PM
                              Ryzen 9 5000 series processor Linus Torvalds2021/01/02 12:21 PM
                                Ryzen 9 5000 series processor Adrian2021/01/02 01:17 PM
                                Ryzen 9 5000 series processor Anon2021/01/02 06:08 PM
                                Ryzen 9 5000 series processor Jukka Larja2021/01/02 11:10 PM
                                  Ryzen 9 5000 series processor David Hess2021/01/03 01:03 AM
                                    Ryzen 9 5000 series processor Jukka Larja2021/01/03 03:28 AM
                                  Threadrippers do have official ECC supportJukka Larja2021/01/03 08:32 PM
                                    Threadrippers do have official ECC supportBjörn Ragnar Björnsson2021/01/04 08:21 AM
                                ECC (or lack of)Tim McCaffrey2021/01/03 09:28 AM
                                  ECC (or lack of)Adrian2021/01/03 01:14 PM
                                    ECC (or lack of)Yuhong Bao2021/01/03 01:51 PM
                                      ECC (or lack of)Yuhong Bao2021/01/04 06:54 PM
                                        ECC (or lack of)Yuhong Bao2021/01/04 07:04 PM
                                AMD ECC not enabled but says it isIan Cutress2021/01/03 11:09 AM
                                  AMD ECC not enabled but says it isMaxwell2021/01/03 12:28 PM
                                  AMD ECC not enabled but says it isAdrian2021/01/03 12:50 PM
                                    AMD ECC not enabled but says it isGabriele Svelto2021/01/03 01:08 PM
                                      AMD ECC not enabled but says it isAdrian2021/01/03 01:34 PM
                                        AMD ECC not enabled but says it isDan Strother2021/01/03 07:00 PM
                                          AMD ECC not enabled but says it isMatt2021/01/04 12:29 AM
                                          AMD ECC not enabled but says it isGabriele Svelto2021/01/04 01:29 AM
                                            AMD ECC not enabled but says it isMatt2021/01/04 12:39 PM
                                          AMD ECC not enabled but says it isAdrian2021/01/04 05:49 AM
                                Ryzen 9 5000 series processor Jason Snyder2021/01/04 01:44 PM
                                  Ryzen 9 5000 series processor Brett2021/01/04 05:08 PM
                                  Ryzen 9 5000 series processor Linus Torvalds2021/01/05 12:29 PM
                                    Ryzen 9 5000 series processor Adrian2021/01/05 01:08 PM
                                    Ryzen 9 5000 series processor Emil Briggs2021/01/05 04:40 PM
                                      Ryzen 9 5000 series processor Gabriele Svelto2021/01/06 01:12 AM
                                    Ryzen 9 5000 series processor [ECC summary - Suitable for framing]Björn Ragnar Björnsson2021/01/05 06:29 PM
                                    Ryzen 9 5000 series processor 2021/01/06 09:45 AM
                                      Ryzen 9 5000 series processor Linus Torvalds2021/01/06 11:38 AM
                                        Ryzen 9 5000 series processor Emanuel Rylke2021/01/07 12:49 AM
                                          Ryzen 9 5000 series processor Jörn Engel2021/01/07 09:05 AM
                                            Read Only Page CorrectionsTerry Gray2021/01/07 09:47 AM
                                              Read Only Page Correctionsrwessel2021/01/07 11:00 AM
                                                Read Only Page CorrectionsTerry Gray2021/01/07 11:58 AM
                                              Read Only Page CorrectionsDavid Hess2021/01/10 07:37 PM
                                              Read Only Page Correctionsdmcq2021/01/11 03:32 AM
                                        Ryzen 9 5000 series processor Chester2021/01/07 05:00 AM
                                          Ryzen 9 5000 series processor Gabriele Svelto2021/01/07 05:33 AM
                                            Ryzen 9 5000 series processor Michael S2021/01/07 08:05 AM
                                              Ryzen 9 5000 series processor Linus Torvalds2021/01/07 10:26 AM
                                            Ryzen 9 5000 series processor rwessel2021/01/07 09:06 AM
                                          Ryzen 9 5000 series processor Linus Torvalds2021/01/07 10:04 AM
                                            Ryzen 9 5000 series processor Chester2021/01/07 04:19 PM
                                              OT L1 chache ECCMichael S2021/01/08 02:31 AM
                                                OT L1 chache ECCAdrian2021/01/08 08:54 AM
                                                  OT L1 chache ECCDavid Kanter2021/01/08 09:13 AM
                                                    Structure ProtectionsChester2021/01/08 02:14 PM
                                            Ryzen 9 5000 series processor Etienne Lorrain2021/01/08 01:18 AM
                                          Ryzen 9 5000 series processor Björn Ragnar Björnsson2021/01/07 05:42 PM
                                            Ryzen 9 5000 series processor Chester2021/01/07 08:14 PM
                                              Ryzen 9 5000 series processor Björn Ragnar Björnsson2021/01/07 08:26 PM
                                                Ryzen 9 5000 series processor Michael S2021/01/08 02:49 AM
                                    Ryzen 9 5000 series processor Jason Snyder2021/01/14 07:32 AM
                                      Ryzen 9 5000 series processor Gabriele Svelto2021/01/15 05:26 AM
                                        Ryzen 9 5000 series processor Jason Snyder2021/01/16 10:45 AM
                                          Ryzen 9 5000 series processor Jason Snyder2021/01/16 12:27 PM
                              Ryzen 9 5000 series processor Etienne Lorrain2021/01/07 01:21 AM
                                Ryzen 9 5000 series processor anon2021/01/07 02:21 AM
                                  Ryzen 9 5000 series processor Etienne Lorrain2021/01/07 03:22 AM
                                    Ryzen 9 5000 series processor Konrad Schwarz2021/01/07 05:27 AM
                                  Ryzen 9 5000 series processor Adrian2021/01/07 04:22 AM
                                  Ryzen 9 5000 series processor rwessel2021/01/07 09:25 AM
                                    Ryzen 9 5000 series processor Jörn Engel2021/01/07 04:29 PM
                                      Ryzen 9 5000 series processor rwessel2021/01/07 06:47 PM
                                        Ryzen 9 5000 series processor David Hess2021/01/11 04:26 AM
                                          Ryzen 9 5000 series processor Adrian2021/01/11 05:25 AM
                                          Ryzen 9 5000 series processor rwessel2021/01/11 07:24 AM
                                      Ryzen 9 5000 series processor Mark Roulo2021/01/07 07:00 PM
                                        Ryzen 9 5000 series processor Björn Ragnar Björnsson2021/01/07 07:20 PM
                                  Ryzen 9 5000 series processor David Hess2021/01/11 04:16 AM
                      Ryzen 9 5000 series processor Jukka Larja2021/01/01 10:43 AM
                        Ryzen 9 5000 series processor David Hess2021/01/01 12:31 PM
                          Ryzen 9 5000 series processor Dan Strother2021/01/01 01:12 PM
                        Ryzen 9 5000 series processor Adrian2021/01/01 01:28 PM
                          Ryzen 9 5000 series processor vs. M1Adrian2021/01/02 02:45 AM
                            Ryzen 9 5000 series processor vs. M1Dummond D. Slow2021/01/02 12:50 PM
                              Ryzen 9 5000 series processor vs. M1Adrian2021/01/02 02:00 PM
                                Ryzen 9 5000 series processor vs. M1Dummond D. Slow2021/01/04 12:11 PM
                            Ryzen 9 5000 series processor vs. M1Dummond D. Slow2021/01/07 10:43 AM
                              Ryzen 9 5000 series processor vs. M1Adrian2021/01/08 08:28 AM
                                Ryzen 9 5000 series processor vs. M1 Sorry, typo, correction hereAdrian2021/01/08 08:31 AM
                                  Ryzen 9 5000 series processor vs. M1 (vs. Rocket Lake)Dummond D. Slow2021/01/22 07:02 AM
                            isn't that an interesting contradiction?hobold2021/01/08 12:44 PM
                              isn't that an interesting contradiction?Maynard Handley2021/01/08 01:27 PM
                              isn't that an interesting contradiction?Adrian2021/01/08 02:21 PM
                                isn't that an interesting contradiction?Maynard Handley2021/01/08 03:59 PM
                                  isn't that an interesting contradiction?Maynard Handley2021/01/08 04:34 PM
                                    isn't that an interesting contradiction?Maynard Handley2021/01/08 04:34 PM
                                    isn't that an interesting contradiction?Maynard Handley2021/01/08 04:35 PM
                                      isn't that an interesting contradiction?Adrian2021/01/09 12:55 AM
                                  isn't that an interesting contradiction?Adrian2021/01/09 12:48 AM
                                    isn't that an interesting contradiction? - gmpAdrian2021/01/09 08:00 AM
                                      isn't that an interesting contradiction? - gmpnone2021/01/11 01:26 AM
                                        isn't that an interesting contradiction? - gmpAdrian2021/01/11 04:34 AM
                                          Fully agree with you, I was just giving some data :-) (NT)none2021/01/11 05:17 AM
                                          isn't that an interesting contradiction? - gmpanon2021/01/11 12:09 PM
                                            isn't that an interesting contradiction? - gmpAdrian2021/01/12 12:54 AM
                                              isn't that an interesting contradiction? - gmpnone2021/01/12 01:15 AM
                                                isn't that an interesting contradiction? - gmpAdrian2021/01/12 03:37 AM
                                                  isn't that an interesting contradiction? - gmpnone2021/01/12 03:53 AM
                                                    uses of int multiplyhobold2021/01/12 02:51 PM
                                                      uses of int multiplynone2021/01/13 01:11 AM
                                                      uses of int multiplyJörn Engel2021/01/13 12:06 PM
                                                  isn't that an interesting contradiction? - gmpWilco2021/01/12 04:17 AM
                                                    isn't that an interesting contradiction? - gmpAdrian2021/01/12 05:07 AM
                        Ryzen 9 5000 series processor Gabriele Svelto2021/01/01 03:31 PM
                          Ryzen 9 5000 series processor Jukka Larja2021/01/01 09:58 PM
                            Ryzen 9 5000 series processor Gabriele Svelto2021/01/02 05:51 AM
                              Ryzen 9 5000 series processor Jukka Larja2021/01/02 07:57 AM
                                Ryzen 9 5000 series processor me2021/01/02 04:30 PM
                                  Ryzen 9 5000 series processor Jukka Larja2021/01/02 10:43 PM
                        Ryzen 9 5000 series processor Björn Ragnar Björnsson2021/01/01 08:41 PM
                          Ryzen 9 5000 series processor Jukka Larja2021/01/01 09:53 PM
                            Ryzen 9 5000 series processor Adrian2021/01/02 01:03 AM
                              Ryzen 9 5000 series processor Jukka Larja2021/01/02 07:39 AM
                          Ryzen 9 5000 series processor Adrian2021/01/02 12:52 AM
                          Ryzen 9 5000 series processor me2021/01/02 05:56 AM
                            Ryzen 9 5000 series processor Michael S2021/01/02 11:41 AM
                              Ryzen 9 5000 series processor Adrian2021/01/02 12:43 PM
                              Ryzen 9 5000 series processor Jukka Larja2021/01/02 10:50 PM
                          Crucial/Micron ECC UDIMMsGabriele Svelto2021/01/02 06:09 AM
                            Crucial/Micron ECC UDIMMsMaxwell2021/01/02 09:45 AM
                              Crucial/Micron ECC UDIMMsYuhong Bao2021/01/02 06:29 PM
                  Ryzen 9 5000 series processor Phil9955112021/01/03 07:46 AM
  Ryzen 9 5000 series processor H_Heckuba2021/01/03 12:06 PM
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