When a buffer is trapped nearly every frame, the cost of trapping and synchronising its contents starts to quickly add up. By always using the megabuffer when this is the case, since megabuffer copies are done directly from the guest, we skip the need to synchronise/trap the backing.
The original intention was to cache on the user side, but especially with shader constant buffers that's difficult and costly. Instead we can cache on the buffer side, with a page-table like structure to hold variable sized allocations indexed by the aligned view base address. This avoids most redundant copies from repeated use of the same buffer without updates inbetween.
Avoids the need to hash PipelineState when we can guess the pipeline that will be used next. This could very easily be optimised in the future with generational, usage-based caching if necessary.
gm20b performs instanced draws by repeating draw methods for each instance, the code to detect this together with the cost of interpreting macros took up around 6% of GPFIFO time in Metro Kingdom. By detecting these specific macros and performing an instanced draw directly much of that cost can be avoided.
gpu-new will use a monolithic pipeline object for each pipeline to store state, keyed by the PackedPipelineState contents. This allows for a greater level of per-pipeline optimisations and a reduction in the overall number of lookups in a draw compared to the previous system.
Caching here was deemed unnecessary since it will be done implicitly by the pipeline cache and creates issues with the legacy attribute conversion pass. It now purely serves as a frontend for Hades.
It was determined that a general purpose Vulkan pipeline cache isn't viable for the significant performance reqs of Draw(), by using a Maxwell 3D specific key we can shrink state significantly more than if we used Vulkan structs.
Removes all usage of graphics_context.h from the codebase, exclusively using the new interconnect and its dirty tracking system. While porting the code a number of bugs were discovered such as not respecting the base instance or primitive type override, which have all been fixed. Currently only clears and constant buffer updates are implemented but due to the dirty state system allowing register handling on the interconnect end there shouldn't end up being many more changes.
This mainly distributes operations down to activeState and pipelineState, aside from clears which are implemented in-place. The exposed interface is much reduced as opposed to the previous GraphicsContext system due to the newly introduced dirty system, this should hopefully make the code more maintainable and keep actual rendering operations seperate from primitive restart state or whatever. Currently draws are unimplemented and the only full implemented things are clears and constant buffer operations.
Active state encapsulates all state that isn't part of a pipeline and can be set dynamically with Vulkan calls. This includes both dynamic state like stencil faces, and command buffer state like vertex buffer bindings.
Simililarly to the last commit, the main goal of this is to reduce the number of redundant work done per draw by employing dirty state as much as possible. Without using dirty state for this every active state operation would need to be performed every draw, which gets very expensive when things like buffer lookups end up being reqiored. Code has also been heavily cleaned up as is described in the previous commit.
The main goal of this is to reduce the number of redundant lookups and work done per draw as much as possible, this is mainly achived through heavy used of dirty tracking though other optimisations like heavily using the linear allocator are also in play. In addition to the goal of performance, the code has been cleaned up and abstracted significantly from its state in graphics_context, hopefully making the GPU interconnect code much more maintainable in the future and reducing the boilerplace needed to add even simple functionality. This commit includes partial pipeline state, enough for implementing clears + a slight bit extra.
