v3dv: add a fast path for vkCmdClearAttachments
Since vkCmdClearAttachments executes inside a render pass, we would
benefit from converting it to a draw within the current subpass job to
improve batching and avoid expensive tile load/store operations.
This can dramatically improve performance for applications using this
command, however, we can only use this if we are clearing the base
layers of framebuffer attachments, since otherwise we would need to
use layered rendering, which we don't support yet.
This improves vkQuake3 performance dramatically (almost 100%
performance improvement at 1080p), which calls this twice per frame.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
5 files changed
