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Thread: Mesa Support For GPU Offloading With GLX DRI3, EGL Wayland

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    Default Mesa Support For GPU Offloading With GLX DRI3, EGL Wayland

    Phoronix: Mesa Support For GPU Offloading With GLX DRI3, EGL Wayland

    Axel Davy has posted a new set of 11 patches to allow for GPU offloading by Mesa 3D drivers with GLX DRI3 and EGL Wayland...

    http://www.phoronix.com/vr.php?view=MTcwMjc

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    Quote Originally Posted by phoronix View Post
    Phoronix: Mesa Support For GPU Offloading With GLX DRI3, EGL Wayland

    Axel Davy has posted a new set of 11 patches to allow for GPU offloading by Mesa 3D drivers with GLX DRI3 and EGL Wayland...

    http://www.phoronix.com/vr.php?view=MTcwMjc
    Michael, is it too much to ask for a bit of context in terms of 'wtf is GPU offloading'?

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    Quote Originally Posted by Akdor 1154 View Post
    Michael, is it too much to ask for a bit of context in terms of 'wtf is GPU offloading'?
    It's using a different GPU for display and rendering.

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    Quote Originally Posted by Akdor 1154 View Post
    Michael, is it too much to ask for a bit of context in terms of 'wtf is GPU offloading'?
    Running your desktop on an Intel GPU, and a game "offloading" to a discrete AMD or NVidia GPU.

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    Quote Originally Posted by smitty3268 View Post
    Running your desktop on an Intel GPU, and a game "offloading" to a discrete AMD or NVidia GPU.
    The better and easier solution for that is to simply *NOT BUY* anything with an intel gpu. Also, would it even be possible to offload to nvidia blob? Because if it isn't, there's no point in offloading to anything besides an AMD. At least not before nouveau matures.... a lot.

    Frankly, multiple-gpu systems are really only interesting in the possibility of using the second gpu for something unrelated to graphics. Or at least not *directly* related to graphics.

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    If they would at least make a direct physical connection from one gpu's buffer space to the other's, so it would have zero performance loss...

    Anyway, on my laptop I'm not sure I don't like it: The intel gpu is really optimized for low power consumption, my HD 7970M not so much. And most often I do only use the intel gpu...

    Also, VRAM. Intel is handling all the window managing and compositing. It's not much, but with compositing and a lot of windows, it still needs memory. I think it does hold quite a bit in VRAM, doesn't it? Anyway, when playing the game, really 100% of the radeon GPU's ressources can go to rendering the game, which would be nice if moving buffers and synchronization would cost nothing.

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    Quote Originally Posted by ChrisXY View Post
    If they would at least make a direct physical connection from one gpu's buffer space to the other's, so it would have zero performance loss...

    Anyway, on my laptop I'm not sure I don't like it: The intel gpu is really optimized for low power consumption, my HD 7970M not so much. And most often I do only use the intel gpu...

    Also, VRAM. Intel is handling all the window managing and compositing. It's not much, but with compositing and a lot of windows, it still needs memory. I think it does hold quite a bit in VRAM, doesn't it? Anyway, when playing the game, really 100% of the radeon GPU's ressources can go to rendering the game, which would be nice if moving buffers and synchronization would cost nothing.
    The VRAM is reserved for your hd 7970m. The intel only uses parts of your ram.

    Both cards share buffers in an area of ram both can access.

    You have to go through the pci express bus to transfer from the hd7970m and its VRAM to the RAM.

    Think it like that:
    if the intel card was reading directly into hd 7970m buffer, it would have to read using the pci express bus.
    It's equivalent to copy via the pci-express bus the buffer in VRAM to a buffer in RAM.
    Except you can read two times from the buffer in RAM without going through the pci-express bus again.
    So what we call a copy (usually bad) is here better.

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    What I meant was that I would have liked it IF when designing these laptops with hybrid gpus they would have created a completely new direct connection from the intel gpu to the radeon vram and then as a layman I would imagine it would just be a driver thing to tell the intel gpu how big the buffer is and when to read out and display what "magically" appeared in the buffer. Not so flexible, but really 99,9% of what most people would want to do and none of this complicated stuff. And why can't the gpu manufacturers that intend to put their two gpus together in one machine just talk to each other so that intel maybe could just implement radeon's tiling format? Are they intentionally making it harder for their driver developers?



    Anyway, I read the mailing list post now.

    There is no need to have a DDX loaded for the device we want to use,
    I always wondered whether it was possible to "detach" a ddx from Xorg after adding it with setprovideroffloadsink because it will always block you from unloading the kernel module without restarting X.
    Now it sounds like it has the nice effect that you can just rmmod radeon whenever nothing is rendering.

    And this way you can easily switch between fglrx+bumblebee (by using LD_PRELOAD, LD_LIBRARY_PATH, LIBGL_DRIVERS_PATH and Xorg's -config and -configdir etc. in a slightly hacky way) and radeon. (Of course only when unloading and loading the different modules repeatedly works reliably)

    There is no need to be in a composited environment.
    So I assume this bug won't be an issue then either? https://bugs.freedesktop.org/show_bug.cgi?id=69101

    Nice. This is great.

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