[Qemu-devel] Performance issues with -usb

[Brad Campbell]

G'day all,

Just a diary note or similar.

I've been playing with skype under win2k under qemu with -kernel-kqemu and the 
alsa audio driver.

1st. The user-net driver appears to be a problem for skype but the tap driver 
works nicely.

2nd. I was having awful problems with the audio. The app was reporting failures of either the dac or 
adc apparently randomly and when it did work it was rather intermittent.

I noticed that with -usb -usbdevice tablet that qemu sits at about 20% cpu usage (on this machine 
which is a Pentium-M 1.2G which idles at 600Mhz) whereas without -usb qemu idles completely.

In addition to this, without -usb.. skype works almost perfectly. There is the occasional audio 
glitch (as you would expect) but it does everything it is supposed to do quite nicely.

I'm using all the latest gear. A 2.6.18-rc2 host kernel, Latest Qemu CVS and the -pre9 kernel 
accelerator. Win2k SP4 as a guest with either 256 or 384M of ram depending on my mood :)

I'm going to have a dig around in the USB stuff when I get the chance, but it's more of a fyi and 
for google that I post it here.

Brad
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