[bisected] Framerate spikes/screen freezing when moving mouse cursor at high pooling rate

[VeilSilence]

Greetings

• NixOS 24.05
• Plasma 6 wayland session.
• Nvidia rtx 3090. Hardware cursors enabled.
• 550.78 driver.
• Gamescope 6f185c7 version

When my mouse is set to an 8000Hz polling rate, every time I see the cursor in-game and move it around the screen, the game basically freezes for about 3-5 seconds (or just straight up crashes) until I stop moving my mouse. At a 1000Hz polling rate, the game no longer freezes, but there is a noticeable framerate/performance drop until I stop moving my mouse.

I bisected the issue to this commit: febcf34. I reverted this commit and built the git version of Gamescope, and it indeed fixed the performance/freezing issue, but I can't click anything in the game now.
Probably commit 7c4438a is the issue, but I couldn't revert this commit and build the Gamescope git version to test it.

This issue probably related to mine also: #1279

[sharkautarch]

Probably commit 7c4438a is the issue

I built gamescope @ 7c4438a and then built gamescope from the commit before it.
And then used ddisasm to disassemble the binaries so I could compare them (with difftastic)
Haven't finished looking thru all the dissassembly, but so far, I can see that just by comparing the assembly for gamescope::CWaylandPlane::Present, it seems that commit 7c4438a has about 6 more mov instructions...
nothing conclusive so far, tho maybe I'll need to do something in wayland_backend.cpp similar to what I did in #1287
I'll have to look more into it...

[VeilSilence]

Oh well, I must apologize for wasting your time.
Problem is still here, I just somehow bisected to wrong commit sadly...
After verifying at least 3 times and even record on video everything, my result of investigations:

Git version gamescope freezing showcase

CPU spikes on cursor move

freezing.mp4

I started bisecting once again.
Gamescope ee02018 commit:

Video showcase. Wrong cursor position, but no framerate spikes. Cursor can interact with game

not.freezeing.Can.interact.with.menus.mp4

Commit 252a189. This is where this problem appears:

Wrong cursor position and frame spikes. Cursor can interact with game

bad.commit.mp4

I was one off of actually problematic commit. In commit 2898cce, my cursor can't interact with game, so framerate was unaffected by this bug...

In the end, I made patch that revert few things from 252a189 commit.
My result on 6f185c7 commit + patch:

Final result. Happy end.

git_revert_patch.mp4

Patch itself

From d0f76adf039f094ea14a2a2b9fe5fc103ab6f968 Mon Sep 17 00:00:00 2001
From: Veil <[e-mail]>
Date: Sun, 19 May 2024 20:54:31 +0300
Subject: [PATCH] Attempt to fix mouse stutters.

---
 src/wayland_backend.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/wayland_backend.cpp b/src/wayland_backend.cpp
index ddc6c10..fffdb98 100644
--- a/src/wayland_backend.cpp
+++ b/src/wayland_backend.cpp
@@ -1927,13 +1927,13 @@ namespace gamescope
     void CWaylandBackend::Wayland_Keyboard_Enter( wl_keyboard *pKeyboard, uint32_t uSerial, wl_surface *pSurface, wl_array *pKeys )
     {
         m_bKeyboardEntered = true;
-
+
         UpdateCursor();
     }
     void CWaylandBackend::Wayland_Keyboard_Leave( wl_keyboard *pKeyboard, uint32_t uSerial, wl_surface *pSurface )
     {
         m_bKeyboardEntered = false;
-
+
         UpdateCursor();
     }

@@ -2309,8 +2309,8 @@ namespace gamescope
     void CWaylandInputThread::Wayland_Pointer_Frame( wl_pointer *pPointer )
     {
         defer( m_uAxisSource = WL_POINTER_AXIS_SOURCE_WHEEL );
-        double x = m_flScrollAccum[0];
-        double y = m_flScrollAccum[1];
+        float x = m_flScrollAccum[0];
+        float y = m_flScrollAccum[1];
         m_flScrollAccum[0] = 0.0;
         m_flScrollAccum[1] = 0.0;

@@ -2320,6 +2320,9 @@ namespace gamescope
         if ( m_uAxisSource != WL_POINTER_AXIS_SOURCE_WHEEL )
             return;

+        if ( x == 0 && y == 0 )
+        return;
+
         wlserver_lock();
         wlserver_mousewheel( x, y, ++m_uFakeTimestamp );
         wlserver_unlock();
--
2.44.0

I'm new to all this git stuff, and also not code developer, so apologize once again for wrong initial report. Hope this helps.

[Joshie]

Does latest master fix the issue for you?

[VeilSilence]

Does latest master fix the issue for you?

Confirm, problem solved.
Thanks.