M1 instruction timings and other details

By: Travis Downs (travis.downs.delete@this.gmail.com), March 7, 2021 10:53 pm
Room: Moderated Discussions
Dougall Johnson has measured and reverse-engineered timing details both the big and little Apple M1 cores.

Interesting observations include that mov immediate (including negated movn) can be eliminated prior to execution (how?) and that the 3c load latency is only for "loads feed load address" scenario, otherwise the latency is 4c. This is similar to the Intel behavior until Ice Lake where the 4c latency was only for load-feeds-load (plus additional restrictons on the addressing expression), otherwise it was 5c and indicates a "load result to AGU" fast path.
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M1 instruction timings and other detailsTravis Downs2021/03/07 10:53 PM
  M1 instruction timings and other detailsanon2021/03/07 11:06 PM
    M1 instruction timings and other detailsTravis Downs2021/03/08 12:19 AM
      M1 instruction timings and other detailsAnon2021/03/08 12:22 AM
        M1 instruction timings and other detailsTravis Downs2021/03/08 12:55 AM
  Validation bufferChester2021/03/08 12:43 AM
    Validation bufferTravis Downs2021/03/08 12:49 AM
      Validation bufferChester2021/03/08 03:25 PM
  Retires, ROB, PRF, LDQ, STQDave Liu2021/03/08 01:39 AM
    Retires, ROB, PRF, LDQ, STQTravis Downs2021/03/08 01:48 AM
      Retires, ROB, PRF, LDQ, STQAnon2021/03/09 12:53 PM
        Retires, ROB, PRF, LDQ, STQDave Liu2021/03/09 04:02 PM
          Retires, ROB, PRF, LDQ, STQTravis Downs2021/03/10 01:43 PM
            Retires, ROB, PRF, LDQ, STQDave Liu2021/03/10 02:22 PM
              Retires, ROB, PRF, LDQ, STQDougall2021/03/10 05:10 PM
                Retires, ROB, PRF, LDQ, STQTravis Downs2021/03/11 12:02 AM
                  Retires, ROB, PRF, LDQ, STQdmcq2021/03/11 08:34 AM
                    Retires, ROB, PRF, LDQ, STQTravis Downs2021/03/11 04:14 PM
                      Retires, ROB, PRF, LDQ, STQDave Liu2021/03/11 05:27 PM
                        Retires, ROB, PRF, LDQ, STQTravis Downs2021/03/11 09:48 PM
                          Branch MicroarchitectureDave Liu2021/03/12 11:59 PM
                            Branch Microarchitectureanon22021/03/13 02:05 AM
                              Branch Microarchitectureanon2021/03/13 03:26 AM
                                Branch Microarchitectureanon22021/03/13 04:34 AM
                                  Branch Microarchitectureanon2021/03/14 05:57 AM
                                    Branch Microarchitectureanon22021/03/14 07:38 PM
                                      Branch Microarchitectureanon2021/03/15 03:14 AM
                                        Branch Microarchitectureanon22021/03/15 04:49 AM
                                Branch Microarchitecture---2021/03/15 11:42 AM
                            Branch MicroarchitectureJon Masters2021/03/13 09:59 AM
                            Branch MicroarchitecturePer Hesselgren2021/03/14 08:26 AM
  Zero latency load immediatePaul A. Clayton2021/03/08 08:52 AM
    Zero latency load immediateanon2021/03/08 12:01 PM
      Zero latency load immediatePaul A. Clayton2021/03/09 06:23 AM
        Zero latency load immediateDave Liu2021/03/14 03:17 AM
          Zero latency load immediateanon2021/03/14 06:04 AM
            Zero latency load immediate---2021/03/15 09:44 AM
    Zero latency load immediateanon22021/03/08 05:43 PM
      Execrable vanity and self-deprecationPaul A. Clayton2021/03/11 11:32 AM
        Execrable vanity and self-deprecationanon2021/03/11 05:43 PM
          Execrable vanity and self-deprecationanonymou52021/03/11 06:52 PM
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          Execrable vanity and self-deprecationanon22021/03/12 07:27 PM
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            [No tech. content] Personality explanationPaul A. Clayton2021/03/14 07:25 AM
        Execrable vanity and self-deprecationJon Masters2021/03/13 09:54 AM
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    Zero latency load immediateJon Masters2021/03/08 10:28 PM
      Zero latency load immediateanon2021/03/09 03:33 AM
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        Can humans read patents?☺dmcq2021/03/09 07:47 AM
          Can humans read patents?☺Anon2021/03/09 03:10 PM
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        Can humans read patents?☺Doug S2021/03/09 09:07 AM
    I'm starting to understandCarson2021/03/09 08:09 AM
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