[Qemu-devel] Re: Extremely slow graphic updates

[Paul Brook <paul@codesourcery.com>]

> What is the quickest way for me to reproduce this problem?
> Have you seen this on ppc emulation only?
>
> I gather that the guest is in text mode. Have you seen this in graphical
> mode too? If yes, what was the resolution of the guest?

Steps to reproduce:
- Start qemu (doesn't matter which target or guest OS).
- Press c-a-2 to switch to the monitor.
- type "help<enter>"
- Watch the output slowly appear over the next 30 seconds

Running qemu over a forwarded X connection from a different machine (i.e. 
ssh -X) suffers a marked slowdown. With this configuration the early x86 boot 
stages are visibly much slower, in addition to the virtual console slowness 
mentioned above.

The monitor virtual console, VGA text mode and the graphical mode used by the 
knoppix bootloader[1] all show marked slowdown. It's unclear whether 
truecolor modes are effected.

[1] I'm guessing this is either VGA 16 color or VESA 256 color mode.

> What is the resolution of your host? What X11 extensions are you using?

I have reproduced on a couple of different machines. Both are fairly standard 
Debian sid installs, without any special Xorg config. One is x86, the other 
x86-64, both 32-bit color depth.
One nVidia FX5200(nv)@800x600, one ATI HD3470(radeonhd)@1600x1200.

> Do you set SDL_VIDEODRIVER anywhere?

No.

Paul