3 ms·

I've got 8GB of RAM on my GPU. Could we stop shuffling it out? Do more of the work there, directly?

dagmx 4y ago
Unintuitively, your two questions are somewhat at odds with each other. The more work you do on the GPU, the more you need to shuffle because the more GPU memory you’d use AND the more state you’d need to check back on the CPU side, causing sync stalls. It’s not insurmountable, and macOS puts a lot more of its work on the GPU for example. Windows is a little more conservative in that regard. Here are some more confounding factors: - Every app needs one or more buffers to draw into. Especially with hidpi screens this can eat up memory quick. The compositor can juggle these to try and get some efficiency, but it can’t move all the state to the GPU due to latency. - you also need to deal with swap memory. You’d ultimately need to shuffle date back to the system ram and then to disk and back which is fairly slow. It’s much better theoretically on APUs though. Theoretically, APUs stand to solve a lot of these issues because they blur the lines of GPU and CPU memory.
SSLy 4y ago
sure https://learn.microsoft.com/en-us/gaming/gdk/_content/gc/system/overviews/directstorage/directstorage-overview https://learn.microsoft.com/en-us/gaming/gdk/_content/gc/sys...
- dagmx 4y ago
  Direct storage doesn’t address the majority of these concerns though. It only means the CPU doesn’t need to load data first to shuffle it over, but it doesn’t help if the CPU does need to access said data or schedule it. It’s largely applicable mainly to games where resource access is known ahead of time.
  - deadly_syn 4y ago
    Wouldnt a desktop interface also be a predefined set of resources? Usually with far less visual flare too.
    - dagmx 4y ago
      Only if you’re dealing with just the desktop environment and don’t allow the user to load applications. Or if those apps also didn’t allow dynamicism of any kind, like loading images from a website

Unintuitively, your two questions are somewhat at odds with each other. The more work you do on the GPU, the more you need to shuffle because the more GPU memory you’d use AND the more state you’d need to check back on the CPU side, causing sync stalls. It’s not insurmountable, and macOS puts a lot more of its work on the GPU for example. Windows is a little more conservative in that regard. Here are some more confounding factors: - Every app needs one or more buffers to draw into. Especially with hidpi screens this can eat up memory quick. The compositor can juggle these to try and get some efficiency, but it can’t move all the state to the GPU due to latency. - you also need to deal with swap memory. You’d ultimately need to shuffle date back to the system ram and then to disk and back which is fairly slow. It’s much better theoretically on APUs though. Theoretically, APUs stand to solve a lot of these issues because they blur the lines of GPU and CPU memory.

SSLy 4y ago

sure https://learn.microsoft.com/en-us/gaming/gdk/_content/gc/system/overviews/directstorage/directstorage-overview https://learn.microsoft.com/en-us/gaming/gdk/_content/gc/sys...

dagmx 4y ago
Direct storage doesn’t address the majority of these concerns though. It only means the CPU doesn’t need to load data first to shuffle it over, but it doesn’t help if the CPU does need to access said data or schedule it. It’s largely applicable mainly to games where resource access is known ahead of time.
- deadly_syn 4y ago
  Wouldnt a desktop interface also be a predefined set of resources? Usually with far less visual flare too.
  - dagmx 4y ago
    Only if you’re dealing with just the desktop environment and don’t allow the user to load applications. Or if those apps also didn’t allow dynamicism of any kind, like loading images from a website