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Old July 18th 20, 05:18 PM posted to alt.windows7.general,alt.comp.os.windows-10,comp.sys.intel,comp.sys.ibm.pc.hardware.chips
Yousuf Khan[_2_]
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Posts: 1,296
Default Linux founder tells Intel to stop inventing 'magic instructions'and 'start fixing real problems'

On 7/16/2020 3:19 PM, VanguardLH wrote:
Already pointed out: your "none of which are being used" is wrong. It
is being used. Video games use it, and those are not rare on Windows
platforms. Any game using DirectX 12 are utilizing AVX2. Scientific,
statistical, financial, encryption, and other programs can use it. Any
program using .NET Framework can use AVX. The latest versions of
Prime95 are optimized to use AVX. While it is used to stress test, that
was not its original or current intent which was to discover prime
numbers. Is prime hunting something that home users do? Of course not,
but it illustrates AVX *is* used.


No, there is a difference between "are utilizing" and "can use". You
used both terms in different sentences up above, probably because you're
not actually sure which one it is, and you wanted to CYA.

"Are utilizing" implies that the games have no choice in the matter, and
they are using AVX even if they don't know it. This would presumably
mean that AVX is being used within the DirectX 12 API itself, and
operates in the background regardless of direct utilization by the game
itself.

That is not how the DX12 API operates. It is a bare-metal API, allowing
the games themselves to control most low-level aspects of the visual
production. This is unlike DX11 the previous API, which was more
hands-on, controlling the low-level aspects. I could see if DX11 had
been further developed, they perhaps might have started to use AVX
within the API itself to help some aspects of performance. But they went
in the completely opposite direction with DX12, I really don't see how
AVX benefits the DX12 low-level API, as it's mainly just a series of
calls to the GPU. For DX12, the "can use" AVX is the appropriate term,
not the "are utilizing".

But even within the game itself over the level of the API, AVX
utilization is very rare. Games could use AVX even under DX11 or even
DX9 or 10 beforehand, but it just didn't use it in the API. There was no
prohibition of using AVX within the application itself. These days they
are more likely to pass off most FP calculations off to the GPU than to
try to do it within the CPU anymore, so AVX is dead in the water.

https://www.tomshardware.com/reviews...de,5461-2.html
"By default, Prime95 automatically selects the newest instruction set
extension, such as AVX, AVX2, or even AVX-512."

Your claim AVX is not used is false.


On the contrary, this exactly proves my point. Torvalds was complaining
about how it's only being used in benchmarks but no real apps. Prime95
is exactly an example of a benchmark and stress testing app. Nobody is
actually using Prime95 for anything other than stress testing and
benchmarking. It's not like as if you're going to be finding any new
prime numbers with a PC anymore, those have now firmly entered the realm
of supercomputers/HPC.

Yousuf Khan