Hi,

I am trying to upload multiple (say n) textures (BC7) to the gpu each frame (there's data every frame read from CPU; there is no way around this), and I am trying to minimize this time as much as possible, was wondering if anyone has any insights other than what I've done:

- each texture is dynamic, have 2 copies (total 2n textures) and interchange between a cpu mapped (D3D11_MAP_WRITE_DISCARD) version to copy data into and gpu unmapped to use for render

- each texture has 2 corresponding resources, a default & a staging version (2n staging, 2n default), map with D3D11_MAP_WRITE and CopyResource (n times each) to default from staging

- have a staging & default texture2darray (array size = n, 2 staging, 2 default), call map D3D11_MAP_WRITE once per frame on staging, CopyResource once to copy and unmap once.

- I also want to try 3d textures, but the limitation of 2048x2048x2048 means i can't use it.

All of these are approximately the same times. Does anyone have thoughts on how I can hide/reduce this time?

I am aware GPU has compute/copy/3d engines (exposed in D12), but is there anyway to parallelize whatever unmap/copyresource is doing to a separate engine from the 3d engine on D11? If not any suggestions/thoughts?

Thanks

I am not sure if PCIe is the problem, I have maybe 40MB per frame (with PCIe3.0 x16 for 32GB/s), and I am already double buffering (with a frame delay) to hide the memcpy operation. However, I was thinking earlier, it seems using staging/default approach, the time is not in the unmap, but copyresource. Does D11's CopyResource automatically use the Copy Engine and not stall the 3D Engine (if there is no dependency)? Or would I have to use D12 for that? I'll have to test that out with triple buffering and 2 frames delay I guess. :D

2048^3 is limiting cause my widths are > 2048 (height and depth are fine).

I am measuring GPU times.

- in dynamic case, I put gpu ticks around unmap

- in default & staging case, unmap doesn't take time, but CopyResource is where the time is

- in default/staging with texture2darray, same as 2nd case.

I also want to try 3d textures, but the limitation of 2048x2048x2048 means i can't use it

Perhaps this is not a relevant suggestion, but is it possible to use a texture array instead of one big volume texture?

Unmap will only trigger the upload, which, when done with DMA, will not involve the GPU. But CopyResource, when you try to access the memory block, will spent time in

To measure the first delay try to use some fence and try to measure the time spend in waiting for the fence:

Does that mean unmap for Dynamic Textures triggers some sort of copy from cpu-accessible gpu memory to default gpu memory internally since that takes about same time as unmap/copyresource for staging/default textures.

Also possibly dumb question, how would you setup a memory fence on DX from the CPU?? There is no query for that, and everything seems to be implicit...

Perhaps this is not a relevant suggestion, but is it possible to use a texture array instead of one big volume texture?

I did try texture arrays already, that was the 3rd thing I tried in my original post.. sorry if it was misleading.

How much time exactly is your 40MiB copy operation currently taking with any of your methods?

Well, another limit is that you'd need a video card with over 8GiB of RAM, which pretty much limits your min-spec hardware to the US$999 GeForce GTX Titan X :wink: :lol:

Hey sorry but not sure what you meant by how long 40MB copy operation is taking? If you mean the methods I've tried above, they are all in the upper 3 ms ballpark (3.6 - 3.9).

Yea I am aware of the large memory video card, I am working on other forms of compression as well, but just want to get this down with BC7 for now :D

So tried the triple buffering approach hoping CopyResource is async dma, but it still stalls the gpu command. :(

Also since d11 device is free threaded, I tried to do something real "dumb" of creating another thread and just keep deleting old/creating new textures (with new content) on this other thread, hoping the texture creation/deletion is async from the gpu graphics engine, and that plan fell flat as well. Even though device is free threaded from the context, apparently creating/deleting resources still runs in same pipeline as the context commands. :(

Any other thoughts/ideas would be appreciated.