Fastmem

[Miksel12]

As far as I know, Yuzu doesn't use Fastmem. But the performance on a modern midrange pc seems to be really good when using Yuzu. This PR for Dynarmic: https://github.com/MerryMage/dynarmic/pull/528 adds Fastmem but it seems that the performance difference is not as big as with Dolphin. With Dolphin the difference I have seen between Fastmem and non-Fastmem can range between 1.5 and 4x.

I was wondering if this is because of the difference between Wii and Switch or if the implementation is different?

[merry]

dynarmic has multiple methods for memory access.

The simplest method is with callbacks on each memory read / write. This is what dolphin does when fastmem is disabled (± some optimisations around predictable addresses).

One thing that dynarmic does that dolphin does not is: Inlining page-table access code into emitted code. This is much faster than a function call.

Fastmem does not really as big of a speed improvement over inlined page-table access because it's a smaller reduction in codesize per emulated memory access.

[Miksel12]

I see, thanks for your answer. Is implementing inlined page-table in Dolphin possible? And would/could it make memory locking trivial performance wise?