Emotion - Does it work under QEMU?

@smarkusg

Im used only gtk for qemu. Is there benefit to use sdl instead?

@Mlehto
Changes to the mplayer (sdl) settings must be made under AmigaOS4.
I use QEMU on a Mac Mini M1. My audio and video outputs are native to Apple's “cocoa”

@Mlehto
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The default TB cache size is 1/8th of host memory or 1GB otherwise so in your case the default is also likely 2GB and the tb-size option does nothing for you.
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Having more than 64MB video memory is not possible with sm501 because the register encoding the memory size does not allow more (and drivers probably would not use more either). The default is already the maximum the sm501 can support so the option could only decrease it and only some specific power of 2 values are valid.
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The Linux scheduler should take care of that without nice, what may help a little is pinning the QEMU process to specific CPU cores which some vfio guides suggest but it probably does not make much difference as you noted above.
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Depends on where you get your binary from or how your distro compiled it. Some distros may already use optimised settings others may be more conservative.
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How did you measure that? Disabling mttcg might avoid some locking that is not needed for single vCPU but this should not have noticable overhead. If it has maybe this should be investigated or have QEMU automatically disable it for machines with single CPU.
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Currently it has a limit that makes it slower than expected and as smarkusg noted it may be worse with RX cards so probably HD cards work the best now. The limit is not fully understood, even on real machines there seems to be some issue but on QEMU it's even worse. I have a theory on the QEMU side but did not have time to investigate. Maybe I try to bring that up on the QEMU list and see if somebody there has an idea on how to improve it. But at least vfio passthrough allows using 3D and should be faster than software rendering.

@smarkusg

Yes, I've modified the settings for mplayer to use sdl for both audio and video. It has improved, but not completely fixed the stuttering and out of sync mouse to voice sounds.

@n3m3
You haven't shared enough info on what machine you run QEMU on. All you said so far that you're using QEMU 9.2.1 via Kyvos but no idea on what host OS, what CPU, what sound backend, what soundcard under which AmigaOS version. It's hard to tell what could be your issue or how could it be improved without more info. It could be that your machine is not fast enough, could be the QEMU version is too old or not compiled with optimal settings but we don't know what machine, what host OS you use and where did you get QEMU from for it so we can't tell if anything could be improved. With the info available so far the only thing I can say to answer your question is to try latest QEMU on the fastest machine you have.

@balaton

- Debian 13 Trixie
- GMKTec G5 Mini (Computer)
- QEMU from debian repository

Kyvos

- CPU = default
- Memory = 2048
- Display = sm501
- Renderer = gtk

@n3m3
Quote:
This has an Intel Alder Lake N97 CPU which only has 2GHz E-cores that can only turbo boost to 3.6GHz for limited time. It's not very fast so this may be pushing its limit. For QEMU single core performance is needed so a faster i5 or i7 should run better which have 3GHz base clock and turbo boost around 4GHz.
Quote:
The patch that sets try-poll=off default for alsa backend was from this March so only present in QEMU 10.1. This is known to cause sound issues in earlier version which need the command line option mentioned above but if you're not using alsa then that's not causing it. I don't know how Kyvos configures audio. If you can set it you could try alsa with try-poll=off or jack that have lower latency than pulseaudio or pipewire and maybe try -device ES1370 instead of via-ac97 but I don't know if any of this helps or how to configure it with Kyvos and what default sound server Debian uses and how to change that.

In general, it would be nice to specify the thresholds at which emulation works.
It would be useful for everyone to know what to expect when running qemu-ppc.
Some simple test that can run qemu-ppc even on Linux, not just on AOS4 itself.

I remembered something that @balaton created some time ago.
link - > http://zero.eik.bme.hu/~balaton/qemu/amiga/pegasos2-lame-test.zip
LAME test posts to run on QEMU PPC.
The time results would be a reference to the speed of qemu-ppc.
If it is lower than the set threshold, the emulation may run slower; if it is above the set threshold, the emulation should run at a satisfactory speed.

@walkero
This may also be useful for Kyvos. It could be added “check system speed under Qemu-ppc”.
The sources (linux kernel/LAME) are GPL, so nothing would violate any license.

@balaton

Server String: /run/user/1000/pulse/native
Library Protocol Version: 35
Server Protocol Version: 35
Is Local: yes
Client Index: 497
Tile Size: 65472
User Name: niter3
Host Name: amiga
Server Name: PulseAudio (on PipeWire 1.2.7)
Server Version: 15.0.0
Default Sample Specification: float32le 2ch 48000Hz
Default Channel Map: front-left,front-right
Default Sink: alsa_output.pci-0000_00_1f.3.hdmi-stereo
Default Source: alsa_input.usb-CSCTEK_USB_Audio_and_HID_A34004801402-00.mono-fallback
Cookie: 4d90:bce8

Just updated to Ubuntu 25.10 which incluces QEMU version 10.

Still no dice. Is it safe to say it's because of the host computer just being to slow?


QEMU emulator version 10.1.0 (Debian 1:10.1.0+ds-5ubuntu2)
Copyright (c) 2003-2025 Fabrice Bellard and the QEMU Project developers

@smarkusg
It might be difficult to give one number to check if your machine is fast enough because it also depends on what you want to do with it. It might be fast enough e.g. for software development which isn't time critical (the compilation would take longer but succeeds and you can use it on a laptop) but not fast enough to run a game or other time critical stuff. It also depends if the time critical app is using more FPU or software rendering or can do with integer only. Kinda like is A1222 fast enough? Depends on what you run on it.

@balaton

Seems I can play some 2d style games. I'm finding in full screen it's off though. The graphics are like overlaying on it each other. If I go to window mode it displays correctly?

@n3m3
A faster machine would definitely help. If you don't want to try to find what causes the issues you see and tweak it more then there's not much else to do. Trying different audio backends or ES1370 instead of via-ac97 might still worth a try and compiling QEMU with additional optimisation could help a bit but maybe not much. I think pulsaudio/pipewire can add latency but should not produce choppy sound but I haven't tested that. Plain ALSA with latest QEMU or jack should have lower latency and may work better. You can also try tweaking the sound buffer options as shown above by Mlehto and see if that helps. It also depends on what you play sound with in AmigaOS so does this happen with all sound or just the app you want to use?

@balaton

So moved things over to a GMKTec K8 Plus.

Still the same results.

Here is the config file kyvos is using.

{
"args": {
"hd1": "",
"machine": "-M pegasos2",
"bios": "",
"loader": "-kernel \"/home/niter3/.kyvos/bboot\" -initrd /home/niter3/Downloads/kyvos_gui/amigaos4/kickstart.zip",
"clock": "-rtc base=localtime",
"vga": "-vga none",
"accel": "-accel tcg",
"tablet": "",
"serial": "-serial stdio",
"network": "-device rtl8139,addr=0x09,netdev=nic -netdev user,id=nic,hostname=amigaos4-1",
"serial_output": "",
"display": "-display sdl,gl=off,show-cursor=off,full-screen=off",
"sound": "-audiodev alsa,id=audio0,out.try-poll=off -device es1370,addr=0x08,audiodev=audio0",
"name": "-name amigaos4-1",
"usb": "",
"hd2": "",
"memory": "-m 1024M",
"cd0": "-drive if=none,id=cd -device ide-cd,drive=cd,bus=ide.1",
"gfx": "-device sm501",
"cpu": "",
"hd0": "-drive if=none,id=hd0,file=/home/niter3/Amiga4/amigahd.img,format=raw -device ide-hd,unit=0,drive=hd0,bus=ide.0",
"usbpath": "",
"pidfile": ""
},
"params": {
"serial_output": "off",
"media": {
"cd0": {
"file": "",
"format": "raw"
},
"usb": {
"path": ""
},
"hd1": {
"file": "",
"format": ""
},
"hd0": {
"file": "/home/niter3/Amiga4/amigahd.img",
"format": "raw"
},
"smb": {
"path": ""
},
"hd2": {
"file": "",
"format": ""
}
},
"machine": "pegasos2",
"gfx": "sm501",
"memory": "1024",
"display": {
"fullscreen": "off",
"zoom_to_fit": "off",
"device": "sdl",
"gl": "off",
"zoom_interpolation": "off",
"show_cursor": "off"
},
"cpu": "",
"network": {
"addr": "0x09",
"hostfwd": [],
"hostname": "amigaos4-1",
"device": "rtl8139",
"netdev": "user"
},
"sound": "es1370",
"tablet": "off"
}
}