Status update from kd-11 (23-06-2021)

Hi,

It's kd-11 here with another progress update for RPCS3.

For the past month, I have been focused on bugfixes as well as some surface cache tweaks and investigations on the side which I will explain. Let's start with some highlights:

1. Fixed performance on linux when using the RADV vulkan driver which improved performance by over 100% in some GPU-limited cases. This driver is recommended over the official AMDVLK driver by AMD. Performance now beats the windows setup in most titles which is good news for AMD+linux users.

2. Fixed crashing in some titles when resolution scaling was enabled. This was a regression going back a few months that randomly caused game instability.

3. Improved compatibility with lower-end hardware such as intel IGPs. This allows running with out of the box settings without crashing the drivers on linux for example. It also allows the software vulkan driver to work which is critical for enabling automated testing down the road. This will help us catch regressions much earlier, improving the user experience with rpcs3.

4. Added support for 'vulkan input attachments' which allows us to do some tricky operations without violating the vulkan specification and sometimes crashing. This lays the groundwork for some future work coming to the vulkan backend.

5. Fixed gamma pack/unpack in RSX shaders. This solved a long-standing issue with some games having very dark output (e.g Shoot Many Robots)

6. Fixed a bug where the emulator would crash with "unsupported image layout 0x5" error message in many games.

7. Fixed some texture and surface cache bugs that would cause crashing. This fixed many games such as Gran Turismo 6 and Madden 17 that would randomly crash before going ingame.

8. Added a workaround for NVIDIA users to account for arithmetic drift in fragment attribute interpolation. Modern NVIDIA hardware does this interpolation at a lower precision than RSX and through arithmetic operations some small errors can become magnified to the point of causing severe visual corruption. Solved a long-standing bug with Hyperdimension Neptunia series when using an NVIDIA card.

9. Fixed a bug where booting different games without closing the emulator in between could crash the Vulkan renderer.

10. Fixed a long-standing bug that caused severe graphics corruption in some games such as the Ace Combat series, Twisted Metal, Viking: Battle for Asgard, Lair, GTA V etc

11. Fixed a bug where 100% CPU usage on one processor core could appear and affect performance on low end devices as well as waste CPU resources.

Finally, a separate set was included that lay the groundwork for upcoming surface cache improvements. This particular change improves image stability when the Write Color Buffers option is enabled and avoids flickering or flashing in some specific situations. There are two more major changesets planned for this task over the coming weeks and will culminate in an overhaul in managing all the different buffer synchronization options such as "Write Depth Buffer", "Write Color Buffers", etc to make them more coherent and easier for users to configure. Since this work can introduce performance regressions easily, I'm pushing the commits out slowly. Thanks to some debugging visualization tools I added over the previous weeks, I have identified even more potential causes of graphical corruption which is very common especially when running AAA games without any patches. I will offer updates on this task as I continue to make progress.

Thank you all for your continued support.

Regards,

kd-11