Emulator Performance - libretro_wii

[radicalten]

Hello,

I wanted to document your emulator's current performance on wii using the libretro frontend:

Version/Release: v1.5: 2025-09-20_Retroarch.7z

Most games tested ran at approximately ~36fps (Sonic the Hedgehog 1-3, Dr. Robotnik's Mean Bean Machine, Outrun, etc.)

Thank you for your work on this emulator!

[Clownacy]

I have a few ideas in the works for how to optimise the emulator:

• Eliminate the VDP blitting look-up table, and just compute the blit directly.
  • Should be easier on the CPU cache.
• Implement a form of memoisation in the CPU bus callbacks by caching direct address-to-memory accesses.
  • Should greatly improve speed of accesses to RAM.
• Implement a CPU instruction cache.
  • Allows the instruction decoder to be skipped in most cases.
• Have the emulator core access the ROM buffer directly, rather than through a callback to the frontend.
  • Should reduce overhead.
• Overhaul how frontend callbacks are handled, to be resolved by the linker rather than relying on something akin to C++ virtual methods.
  • Should also reduce overhead.
• Evaluate CPU condition codes in a 'lazy' manner, only computing them when absolutely necessary.
  • Should improve the speed of almost every instruction by avoiding unnecessary work.
• Have the 68000 interpreters process instructions in batches, avoiding the need to constantly call 'setjmp' and reconstruct the 'stuff' struct.
  • Should also improve the speed of every instruction.

[Clownacy]

fc7da39 makes the core access the ROM buffer directly.

This commit makes the 68000 interpreter batch instructions.

[radicalten]

Great work!

If you push this as a new release to clownmdemu-libretro, I could give updated figures for wii.

Currently the release version for clownmdemu-libretro is v1.5, which does not yet include your changes.

[Clownacy]

Libretro's build-bot uses the latest commit, which is 7591c16.

[radicalten]

Thank you for the link,

After testing it would appear that, at least on the wii, these titles have similar performance before and after the 7591c16 commit ~36fps (approximately 35.5-36.5fps).