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Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak

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Am 07.12.2021 um 19:49 schrieb Scott Lurndal:
> Bonita Montero <Bonita.Montero@gmail.com> writes:
>> Am 07.12.2021 um 19:06 schrieb Scott Lurndal:
>>> Bonita Montero <Bonita.Montero@gmail.com> writes:
>>>> Am 06.12.2021 um 19:02 schrieb Scott Lurndal:
>>>>
>>>>> Some processors will acquire the cacheline into the nearest
>>>>> cache to ensure exclusive access for the add, while
>>>>> others will pass the entire operation to the last-level cache
>>>>> where it is executed atomically.
>>>>
>>>> There's for sure no architecture that does atomic operations in
>>>> the last level cache because this would be silly.
>>>
>>> Well, are you sure?  Why do you think it would be silly?
>>>
>>> https://genzconsortium.org/wp-content/uploads/2019/04/Gen-Z-Atomics-2019.pdf
>>>
>>> Given that at least three high-end processor chips have taped out just
>>> this year with the capability of executing "far" atomic operations in
>>> the LLC (or to a PCI Express Root complex host bridge), I think you
>>> really don't have a clue what you are talking about.
>>
>> And which CPUs currently support this Gen-Z interconnect ?
> 
> I'd tell you, but various NDA's forbid.

LOOOOOOOL.

>> And which CPUs currently use this far atomics for thread
>> -synchronitation - none.

> How do you know?

Because this would be slower since the lock-modifications
woudln't be done in the L1-caches but in far memory. That's
just a silly idea.

> I'm aware of three. Two sampling to customers, with  core
> counts from 8 to 64. 

And you can't tell it because of NDAs. Hrhr.

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Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-05 18:13 +0100
  Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-05 19:56 +0000
    Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-05 15:22 -0800
      Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-05 23:43 +0000
        Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-05 19:31 -0800
      Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-06 06:26 +0100
    Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-06 06:24 +0100
      Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-12-06 10:45 +0000
        Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-06 13:09 +0100
  Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-06 06:27 +0100
  Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak scott@slp53.sl.home (Scott Lurndal) - 2021-12-06 18:02 +0000
    Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-07 06:27 +0100
      Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak scott@slp53.sl.home (Scott Lurndal) - 2021-12-07 18:06 +0000
        Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-07 19:14 +0100
          Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak scott@slp53.sl.home (Scott Lurndal) - 2021-12-07 18:49 +0000
            Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-07 19:54 +0100
              Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak scott@slp53.sl.home (Scott Lurndal) - 2021-12-07 19:14 +0000
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak scott@slp53.sl.home (Scott Lurndal) - 2021-12-07 19:25 +0000
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-08 09:50 +0100
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-12-08 00:59 -0800
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-08 15:41 +0100
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak scott@slp53.sl.home (Scott Lurndal) - 2021-12-08 15:48 +0000
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Bonita Montero <Bonita.Montero@gmail.com> - 2021-12-08 17:35 +0100
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Öö Tiib <ootiib@hot.ee> - 2021-12-08 10:57 -0800
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Manfred <noname@add.invalid> - 2021-12-09 00:27 +0100
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak Juha Nieminen <nospam@thanks.invalid> - 2021-12-09 06:30 +0000
                Re: Little program to test concurrency of .fetch_add and .compare_exchange_weak David Brown <david.brown@hesbynett.no> - 2021-12-08 09:08 +0100

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