Status update from kd-11 (2020-11-01)

Hi,

It's kd-11 with an RSX emulation update for the month of October 2020. 

I'd first like to apologize for the delay in releasing this update; I pushed it back by a week to try and finish the shader decompiler rewrite which is still not ready for release unfortunately.

For the month of October, a lot of time was spent doing R&D for some other planned features and updates. There were also bugfixes and some rewrites. To summarize:

• 1. RSX reservation rewrite was finally rebased and merged. There is only one known regression with L.A Noire, but it is unclear if the code caused the regression or the game's instability just got worse because things now run even faster than before.
• 2. GPU query management was rewritten. This fixed a lot of problems with ZCULL in games where flickering was observable. Many AAA games were affected by this problem, from RDR to every Unreal Engine 3 game. The previous method of keeping a small pool of queries around and reusing them when we decided they were no longer needed was broken, now a query pool is created and used only once. After it has been exhausted it is disposed of and a new one is allocated. This happens rarely (maybe once per minute in heavy titles) so there is no negative performance impact.
• 3. Fixed a fatal crash that happened in games such as Siren: Blood Curse caused by inconsistent commandbuffer state.
• 4. Fixed a fatal crash in NCAA14 due to some incomplete code from the depth float support patches.
• 5. Made some driver compatibility adjustments to warn users about out of date drivers with known problems.
• 6. Fixed a problem that caused rpcs3 to not work on Intel IGPs when using Vulkan.

Apart from these merged changes, there was quite a bit of R&D that is incomplete at the moment.

1. I am still working on the huge shader compiler rewrite. Progress is a bit slow on this one but its getting into shape. The first step of getting all shaders to compile and link from one system has been achieved but threading issues are causing some slight delays. The goal is to drastically lower shader compile times and also allow features such as shader interpreter to work seamlessly. This feature is in progress with ETA of 1 more week.

• 2. During a bugfix I took on to clear my mind while working on the decompilers, I discovered a huge problem in the texture cache page protection system that can cause data to leak and get lost when Write Color Buffers is enabled. While trying to fix that bug, several other serious problems were uncovered and it became an endless rabbit hole of pain. I have uncovered the causes for the issues and I have plans to patch this in, but its a huge job and will require some time to fix correctly. For those interested, you can see the original problem [here] and the followup [here.]

I plan on returning to the main roadmap after that with completed 3D support and the texture cache restructuring task.

Thank you all for your continued support.

Regards,

kd-11