[SOLVED] Really poor performance with xf86-video-amdgpu + compositing

emjustem · 2022-10-05 01:00:25

What I mean by poor performance is that there will be a delay of several seconds when I try to move or resize a window, or right click the desktop to open the menu. There is even a delay of several seconds when I type into xfce terminal between pressing the key and the letter appearing.

Also, glxgears gets only 1fps.

If I turn off compositing in xfce window manager tweaks, then the window manager stuff alleviates, but applications like firefox are still very slow and glxgears still only gets 1fps.

I have an RX 480 which I've connected 3 monitors to (2 2560x1440, 1 1024x768). I also have a Radeon 6800 which is connected to one of the 2560 monitors, but I have disabled that connection; I intend to use that card for gpu passthrough to a VM once I get these other issues figured out (But if nothing is connected to it at all, my bios refuses to boot). I'm running xfce.

If I uninstall xf86-video-amdgpu, then everything works great: glxgears runs at 60, my desktop and all my applications are responsive, except there is some really bad screen tearing. Google says that there's an option to fix tearing... in xf86-vide-amdgpu.

I've uploaded 4 xorg.logs, for each combination of (composting on?) and (xf86 installed?): https://drive.google.com/drive/folders/ … sp=sharing

Here are two of them reupped to pastebin, with-and-without xf86-video-amdgpu: without with

and here is glxinfo -B without and with

Last edited by emjustem (2022-10-09 14:15:54)

seth · 2022-10-05 06:39:14

No preview, no download.
Please see the 1st link below - you only need a log w/ and w/o xf86-video-amdgpu. Whether the compositor is running isn't relevant to the X11 server and has no impact on the log.
Edit: also "glxinfo -B"

Last edited by seth (2022-10-05 06:39:33)

emjustem · 2022-10-05 14:15:14

thanks. edited OP to add those links.

seth · 2022-10-05 14:28:26

[    22.172] (EE) AMDGPU(0): drmmode_do_crtc_dpms cannot get last vblank counter

[    26.849] randr: falling back to unsynchronized pixmap sharing

You're in either case running on the Radeon RX 6800 XT which has one output attached, the thre others are on the Radeon RX 590

I also have a Radeon 6800 which is connected to one of the 2560 monitors, but I have disabled that connection; I intend to use that card for gpu passthrough to a VM

See the second note in https://wiki.archlinux.org/title/PRIME#Reverse_PRIME
I'm pretty sure disabling the GPU or configuring X11 to run on the other (see eg. https://wiki.archlinux.org/title/PRIME# … rimary_GPU for a pattern) will alleviate the problem.

emjustem · 2022-10-08 00:32:28

I've read that section a couple times now to try to understand what's going on.

If the second GPU has outputs that are not accessible by the primary GPU"

What does accessible mean?

This will involve using the primary GPU to render the images, and then pass them off to the second GPU.

I'm not sure that's what I want to do but you did say "disabling the gpu or configuring X11 to run on the other", which does sound like what I want to do, so this quote might not matter

The command xrandr --setprovideroutputsource provider source sets the provider as output for the source. For example:

I think this is one of the parts I want to skip, so all I'm really looking at here is where it makes an edit to xorg.conf to set

Inactive "nvidia"

Does that sound right?... Except I'm not sure what I'd do in my case since both cards use the same driver.

Last edited by emjustem (2022-10-08 02:01:26)

seth · 2022-10-08 07:05:45

What does accessible mean?

It just means that the primary GPU cannot make pixels colorful on those monitors and would need to ask the secondary GPU to do so on itf behalf.

sound like what I want to do, so this quote might not matter

This.

Does that sound right?

No.
1. you don't have an nvidia GPU
2. That's not what the "Discrete card as primary GPU" section says.

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "rx590"
    Inactive "rx6800"
EndSection

Section "Device"
    Identifier  "rx590"
    Driver      "amdgpu"
    BusID       "PCI:4:0:0"
EndSection

Section "Screen"
    Identifier "rx590"
    Device "rx590"
EndSection

Section "Device"
    Identifier  "rx6800"
    Driver      "amdgpu"
    BusID       "PCI:3:0:0"
EndSection

Section "Screen"
    Identifier "rx6800"
    Device "rx6800"
EndSection

emjustem · 2022-10-09 14:15:24

Ok, that seems to have worked. I don't think I'll know for sure until I try to use it for VM passthrough but I can figure that out when I try it. Thank you!

niqingliang2003 · 2022-11-14 05:07:17

I encountered the same problem like that.

I have 7950x'gpu connected to a monotor, and the gtx1070 connected to another monitor.

by default, the system can light them ok, and 7950x's monitor's content is on the right of gtx1070.

when I change the layout of the two monitor by kde's display setting, i.e. put the gtx1070's monitor on the right of 7950x's monitor, the 1fps and lag problem happen.

seth · 2022-11-14 07:49:23

Did you see the note in https://wiki.archlinux.org/title/PRIME#Reverse_PRIME ?

when I change the layout of the two monitor by kde's display setting

We'd need to see your xorg log, https://wiki.archlinux.org/title/Xorg#General and "xrandr -q" output (the latter in the good and the bad case)

Arch Linux

#1 2022-10-05 01:00:25

[SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#2 2022-10-05 06:39:14

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#3 2022-10-05 14:15:14

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#4 2022-10-05 14:28:26

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#5 2022-10-08 00:32:28

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#6 2022-10-08 07:05:45

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#7 2022-10-09 14:15:24

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#8 2022-11-14 05:07:17

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

#9 2022-11-14 07:49:23

Re: [SOLVED] Really poor performance with xf86-video-amdgpu + compositing

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