[Mesa-dev] [Bug 103852] Rendering errors when running dolphin-emu with Vulkan backend, radv (Super Smash Bros. Melee)

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=103852

--- Comment #19 from Ben Clapp <benclapp55 at gmail.com> ---
Hello all, I have some insight and fixes for some of the issues described in
this ticket:

First, regarding the "black screen when cropping is turned on issue", this can
be worked around with the following pull request:
https://github.com/dolphin-emu/dolphin/pull/6786

In theory, there shouldn't be anything wrong with negative Y in the viewport,
and you can still see black screen flickering when adjusting the window size,
but with this change to dolphin's code made, the screen will never remain black
after a resize (only flicker for a moment).
So this issue is probably still worth investigating on the mesa side at some
point.

Regarding the strange stuttering issues I was experiencing, this is a CPU-side
issue that has nothing to do with mesa.
The TR 1950X is essentially two Ryzen chips glued together.
The TR 1950X has two memory controllers, and each memory controller is owned by
one of the two Ryzen chips.
So, for example, I have two 16GB RAM cards plugged into the two memory
controllers on my system, and when running "numactl -H", I can see that 16GB of
RAM are assigned to each of the two NUMA nodes.
It seems that the memory allocator (or maybe the scheduler?) in Linux wasn't
properly allocating memory (or maybe processes) to just one of the two physical
chips/just one of the RAM cards, and this resulted in stuttering (perhaps due
to needing to transfer some memory from one RAM card to the other for use by
another process on the other Ryzen chip?)
The stuttering can be prevented by using numactl like this:
numactl --cpunodebind=0 --membind=0 ./dolphin-emu

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