This fixes a rare bug where reporting a counter for a region containing 0 draws could deadlock the GPU. If this write overlaps with a tracking action, then the GPU could end up waiting on something that it's meant to do in the future, so it would just get stuck.
Before, this reported immediately and wrote the result to guest memory (tracked) from the backend thread.
The backend thread cannot be allowed to trigger read actions that wait on the GPU, as it will end up waiting on itself, and never advancing.
In the case of backend multithreading's `SyncMap`, it would try to wait for a backend sync object that does not yet exist, as the sync object would exist according to the GPU and tracking, but it has not yet been created by the backend (and never will be, since it's stuck).
The fix is to queue the 0 draw event just like any other, its _bufferMap value is just forced to 0.
This affects games that use Conditional Rendering: SMO, Splatoon 2, MK8. Was generally indicated by a red message in log saying that the query result timed out after 5000 tries, but not always the cause.
* Initial Implementation
About as fast as nvidia GL multithreading, can be improved with faster command queuing.
* Struct based command list
Speeds up a bit. Still a lot of time lost to resource copy.
* Do shader init while the render thread is active.
* Introduce circular span pool V1
Ideally should be able to use structs instead of references for storing these spans on commands. Will try that next.
* Refactor SpanRef some more
Use a struct to represent SpanRef, rather than a reference.
* Flush buffers on background thread
* Use a span for UpdateRenderScale.
Much faster than copying the array.
* Calculate command size using reflection
* WIP parallel shaders
* Some minor optimisation
* Only 2 max refs per command now.
The command with 3 refs is gone. 😌
* Don't cast on the GPU side
* Remove redundant casts, force sync on window present
* Fix Shader Cache
* Fix host shader save.
* Fixup to work with new renderer stuff
* Make command Run static, use array of delegates as lookup
Profile says this takes less time than the previous way.
* Bring up to date
* Add settings toggle. Fix Muiltithreading Off mode.
* Fix warning.
* Release tracking lock for flushes
* Fix Conditional Render fast path with threaded gal
* Make handle iteration safe when releasing the lock
This is mostly temporary.
* Attempt to set backend threading on driver
Only really works on nvidia before launching a game.
* Fix race condition with BufferModifiedRangeList, exceptions in tracking actions
* Update buffer set commands
* Some cleanup
* Only use stutter workaround when using opengl renderer non-threaded
* Add host-conditional reservation of counter events
There has always been the possibility that conditional rendering could use a query object just as it is disposed by the counter queue. This change makes it so that when the host decides to use host conditional rendering, the query object is reserved so that it cannot be deleted. Counter events can optionally start reserved, as the threaded implementation can reserve them before the backend creates them, and there would otherwise be a short amount of time where the counter queue could dispose the event before a call to reserve it could be made.
* Address Feedback
* Make counter flush tracked again.
Hopefully does not cause any issues this time.
* Wait for FlushTo on the main queue thread.
Currently assumes only one thread will want to FlushTo (in this case, the GPU thread)
* Add SDL2 headless integration
* Add HLE macro commands.
Co-authored-by: Mary <mary@mary.zone>
* Implementation of query queue and host conditional rendering
* Resolve some comments.
* Use overloads instead of passing object.
* Wake the consumer threads when incrementing syncpoints.
Also, do a busy loop when awaiting the counter for a blocking flush, rather than potentially sleeping the thread.
* Ensure there's a command between begin and end query.
