From: cr88192@gmail.com
On 9/19/2025 12:00 PM, BGB wrote:
> On 9/19/2025 4:50 AM, Anton Ertl wrote:
>> BGB writes:
>>> On 9/17/2025 4:33 PM, John Levine wrote:
>>>> According to BGB :
>>>>> Still sometimes it seems like it is only a matter of time until
>>>>> Intel or
>>>>> AMD releases a new CPU that just sort of jettisons x86 entirely at the
>>>>> hardware level, but then pretends to still be an x86 chip by running
>>>>> *everything* in a firmware level emulator via dynamic translation.
>>>>
>>>> That sounds a whole lot like what Transmeta did 25 years ago:
>>>>
>>>> https://en.wikipedia.org/wiki/Transmeta_Crusoe
>>>>
>>>> They failed but perhaps things are different now. Their
>>>> native architecture was VLIW which might have been part
>>>> of the problem.
>>>>
>>>
>>> Might be different now:
>>> 25 years ago, Moore's law was still going strong, and the general
>>> concern was more about maximizing scalar performance rather than energy
>>> efficiency or core count (and, in those days, processors were generally
>>> single-core).
>>
>> IA-64 CPUs were shipped until July 29, 2021, and Poulson (released
>> 2012) has 8 cores. If IA-64 (and dynamically translating AMD64 to it)
>> would be a good idea nowadays, it would not have been canceled.
>>
>> How should the number of cores change anything? If you cannot make
>> single-threaded IA-32 or AMD64 programs run at competetive speeds on
>> IA-64 hardware, how would that inefficiency be eliminated in
>> multi-threaded programs?
>>
>>> Now we have a different situation:
>>> Moore's law is dying off;
>>
>> Even if that is the case, how should that change anything about the
>> relative merits of the two approaches?
>>
>>> Scalar CPU performance has hit a plateau;
>>
>> True, but again, what's the relevance for the discussion at hand?
>>
>>> And, for many uses, performance is "good enough";
>>
>> In that case, better buy a cheaper AMD64 CPU rather than a
>> particularly fast CPU with a different architecture X and then run a
>> dynamic AMD64->X translator on it.
>>
>
> Possibly, it depends.
>
> The question is what could Intel or AMD do if the wind blew in that
> direction.
>
> For the end-user, the experience is likely to look similar, so they
> might not need to know/care if they are using some lower-power native
> chip, or something that is internally running on a dynamic translator to
> some likely highly specialized ISA.
>
>
>
>>> A lot more software can make use of multi-threading;
>>
>> Possible, but how would it change things?
>>
>
> Multi-threaded software does not tend to depend as much on single-thread
> performance as single threaded software...
>
>
>>> Likewise, x86 tends to need a lot of the "big CPU" stuff to perform
>>> well, whereas something like a RISC style ISA can get better performance
>>> on a comparably smaller and cheaper core, and with a somewhat better
>>> "performance per watt" metric.
>>
>> Evidence?
>>
>
> No hard numbers, but experience here:
> ASUS Eee (with an in-order Intel Atom) vs original RasPi (with 700MHz
> ARM11 cores).
>
> The RasPi basically runs circles around the Eee...
>
>
> Though, no good datapoints for fast x86 emulators here.
> At least DOSBox and QEMU running x86 on RasPi tend to be dead slow.
>
>
>
> ( no time right now, so skipping rest )
>
Seems I have a little time still...
Did find this:
https://browser.geekbench.com/v4/cpu/compare/2498562?baseline=2792960
Not an exact match, I think the Eee was running the Atom at a somewhat
lower clock speed; and this is vs a Pi3 vs original Pi.
The Pi3 having 4x A53 cores.
But, yeah, they are roughly matched on single thread performance when
the Atom has a clock-speed advantage.
Though, this seems to imply that they are more just "comparable" on the
performance front, rather than Atom being significantly slower...
Would need to try to dig-out the Eee and re-test, assuming it still
works/etc.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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