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Hacked Nvidia 4090 GPU driver to enable P2P

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Re: Hacked Nvidia 4090 GPU driver to enable P2P

#34

What does P2P mean in this context? I Googled it and it sounds like it means "peer to peer", but what does that mean in the context of a graphics card?

It means you can send data from the memory of 1 GPU to another GPU without going via RAM. https://xilinx.github.io/XRT/master/html/p2p.html

Re: Hacked Nvidia 4090 GPU driver to enable P2P

#35
post #34

What does P2P mean in this context? I Googled it and it sounds like it means "peer to peer", but what does that mean in the context of a graphics card?

It means you can send data from the memory of 1 GPU to another GPU without going via RAM. https://xilinx.github.io/XRT/master/html/p2p.html

Is this really efficient or practical? My understanding is that the latency required to copy memory from CPU or RAM to GPU negates any performance benefits (much less running over a network!)

Re: Hacked Nvidia 4090 GPU driver to enable P2P

#36

Earlier quoted context omitted.

RTX 40 doesn’t have NVLink on the PCBs, though the silicon has to have it, since some sibling cards support it. I’d expect it to be fused off.

How to unfuse it?

I don't know about this particular scenario, but typically fuses are small wires or resistors that are overloaded so they irreversibly break the connection. Hence the name.

Either done during manufacture or as a one-time programming[1][2].

Though sometimes reprogrammable configuration bits are sometimes also called fuse bits. The Atmega328P of Arduino fame uses flash[3] for its "fuses".

[1]: https://www.nxp.com/docs/en/application-note/AN4536.pdf

[2] https://www.intel.com/programmable/technical-pdfs/654254.pdf

[3]: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7810-...

Re: Hacked Nvidia 4090 GPU driver to enable P2P

#37
post #35
post #34

Earlier quoted context omitted.

It means you can send data from the memory of 1 GPU to another GPU without going via RAM. https://xilinx.github.io/XRT/master/html/p2p.html

Is this really efficient or practical? My understanding is that the latency required to copy memory from CPU or RAM to GPU negates any performance benefits (much less running over a network!)

Yea. It’s one less hop through slow memory

Re: Hacked Nvidia 4090 GPU driver to enable P2P

#38
post #26

Earlier quoted context omitted.

Looks like we're only a few years away from a bona fide cyberpunk dystopia, in which only governments and megacorps are allowed to use AI, and hackers working on their own hardware face regular raids from the authorities.

On one hand I'm strongly against letting that happen, on the other there's something romantic about the idea of smuggling the latest Chinese LLM on a flight from Neo-Tokyo to Newark in order to pay for my latest round of nervous system upgrades.

> On one hand I'm strongly against letting that happen, on the other there's something romantic about the idea of smuggling the latest Chinese LLM on a flight from Neo-Tokyo to Newark in order to pay for my latest round of nervous system upgrades.

At least call it the 'Free City of Newark'

Re: Hacked Nvidia 4090 GPU driver to enable P2P

#39
post #26

Earlier quoted context omitted.

Looks like we're only a few years away from a bona fide cyberpunk dystopia, in which only governments and megacorps are allowed to use AI, and hackers working on their own hardware face regular raids from the authorities.

On one hand I'm strongly against letting that happen, on the other there's something romantic about the idea of smuggling the latest Chinese LLM on a flight from Neo-Tokyo to Newark in order to pay for my latest round of nervous system upgrades.

"The sky above the port was the color of Stable Diffusion when asked to draw a dead channel."

Re: Hacked Nvidia 4090 GPU driver to enable P2P

#40
post #35
post #34

Earlier quoted context omitted.

It means you can send data from the memory of 1 GPU to another GPU without going via RAM. https://xilinx.github.io/XRT/master/html/p2p.html

Is this really efficient or practical? My understanding is that the latency required to copy memory from CPU or RAM to GPU negates any performance benefits (much less running over a network!)

this would be directly over the memory bus right? I think it's just always going to be faster like this if you can do it?
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