Arch Linux

lucasrizzini

Member

From: Rio de Janeiro/Brazil

Registered: 2020-04-22

Posts: 17

Website

Huge performance drop when enable two GPUs

I'm running Arch/KDE Plasma with two GPUs with HDMI cable attached to the primary one.

1. Primary: Intel HD Graphics 4600
2. Secondary: RX580

When I was running with just the RX580 everything was fine. After I changed to the scenario above, I notice huge performance drop on my games. I'm certain that I'm not using my Intel's when running my games. I have no freaking idea of what is happening. Everything seems fine. I can't find anything that could give me a clue.

Xorg conf files:

19-intel.conf: ↓ ↓

Section "Device"
        Identifier  "Intel Graphics"
        Driver      "intel"
        Option      "DRI" "3"         
        Option      "TearFree" "true"
EndSection

20-amdgpu.conf: ↓ ↓

Section "Device"
    Identifier "AMD"
    Driver "amdgpu"
    Option      "DRI"    "3"
EndSection

Logs:
Xorg.0.log -> https://pastebin.com/485DiQyw

vulkaninfo - Ignore the first three lines. - > https://pastebin.com/zEinCDb9

xrandr -> https://pastebin.com/MBYFuYfu

xrandr --listproviders:
Providers: number : 2
Provider 0: id: 0x47 cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 3 outputs: 5 associated providers: 1 name:Intel
Provider 1: id: 0x94 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 5 associated providers: 1 name:Radeon RX 580 Series @ pci:0000:01:00.0

Solved:
The "Option "TearFree" "true"" at my 19-intel.conf was causing it. Unfortunately, I didn't understand why this was happening and why removing the option solved it. Would be very nice if someone could explain this. Thank you, community.

Last edited by lucasrizzini (2020-08-06 00:02:04)

lucasrizzini

Member

From: Rio de Janeiro/Brazil

Registered: 2020-04-22

Posts: 17

Website

Re: Huge performance drop when enable two GPUs

Troubleshooting:
It briefly goes away if I reset Xorg restarting the display manager(SDDM) and doesn't happen on power on or restart.

Last edited by lucasrizzini (2020-08-06 07:55:46)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 21,742

Re: Huge performance drop when enable two GPUs

The Option "TearFree" is a very xf86-video-intel specific option that likely bites itself with what the renderer for amdgpu wants to do. In general from a xorg perspective it would probably be better to use the modesetting driver for the intel... (in general, xf86-video-intel is very sporadically if at all updated) and especially in combination with another GPU.

lucasrizzini

Member

From: Rio de Janeiro/Brazil

Registered: 2020-04-22

Posts: 17

Website

Re: Huge performance drop when enable two GPUs

Same thing occur without TearFree option.