Certain UE4 games create constant buffer of D3D11_USAGE_DEFAULT and update the full content via UpdateSubresource frequently (before every draw call). Albeit I don't understand why they don't use dynamic buffer and map/unmap with MAP_WRITE_DISCARD flag, probably it's an optimized path for the red/green factory. However this introduces a huge performance impact on our current implementation: a render encoder is forced to be cut in the middle point multiple times to insert blit commands in between, thus a lot of unnecessary attachments load/store occur.
Certain UE4 games create constant buffer of
D3D11_USAGE_DEFAULTand update the full content viaUpdateSubresourcefrequently (before every draw call). Albeit I don't understand why they don't use dynamic buffer and map/unmap withMAP_WRITE_DISCARDflag, probably it's an optimized path for the red/green factory. However this introduces a huge performance impact on our current implementation: a render encoder is forced to be cut in the middle point multiple times to insert blit commands in between, thus a lot of unnecessary attachments load/store occur.The absurd dependency graph: