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Up Topic Rybka Support & Discussion / Aquarium / How to configure CUDA backend for LC0?
- - By Ghengis-Kann (***) Date 2019-06-24 16:39
I have 2 video cards in the same computer and want to use both of them as IDEA engines with LC0.

At the top of the engine properties there is a place where I can point to the CUDA backend options, and I would like to define 2 different engines using 1 card each.
It defaults to using GPU 0, so all I have to do is tell the second engine to use GPU 1, but the specific syntax of the file that I have to point it to eludes me.

The LC0 Discord has not been helpful so I'm hoping someone here will know.
Parent - - By dickie (**) Date 2019-06-24 18:16
Parent - - By Ghengis-Kann (***) Date 2019-06-24 19:25
Hi Dickie.

I saw that and created a text file that contained GPU=1, pointed to it in the engine options, and the whole program froze.

It was late and I read it kind of fast, so after looking at it again I have some idea of what to try next.

Maybe backend=cudnn-fp16, (gpu=1)

I will report back after I get home tonight and give it a try.
Parent - - By ChiefPushesWood (**) Date 2019-06-24 22:44 Edited 2019-06-24 22:49
Throwing darts here but don't you have to use Roundrobin (used to be multiplexing) for multiple cards?

Chief

Edit: This is the configuration from TCEC with two cards...

>TCEC:


>backend: roundrobin (starting from current DivP; before it was multiplexing)
>backend-opts: backend=cudnn-fp16,(gpu=0),(gpu=1)

Parent - By Ghengis-Kann (***) Date 2019-06-25 16:23
I've been swamped by job and family so haven't had a chance to try anything out, but my guess is that Roundrobin would be appropriate for using 2 cards simultaneously in IA mode (which is essentially what TCEC does). For IDEA analysis it should be possible to add each card as a completely separate engine.

Thanks for the syntax CPW.
Up Topic Rybka Support & Discussion / Aquarium / How to configure CUDA backend for LC0?

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