[Qemu-devel] Workaround for windbg

[Kazu]

Hi,

My previous patch is not enough to use windbg. A rate of  loop in main_loop
in vl.c drops a lot.

The rate does not drop for Fedora Core 4 guest but not good for RedHat 7.2
and Windows 2000. It is expected at least 1000 cycles/sec, but the rate
drops to 130 cycles/sec while CPU load is high. It is the case while OS is
booting. The rate is slow so that a communication through serial line is
slow.

I made a workaround for it and checked the data sending/receiving rate by
it. The patch exits CPU loop in cpu_exec every 100 times and handle I/O of
serial data. The rate of loop in main_loop is about 30000 cycles/sec. Win2k
booting time with windbg is much improved.

The patch is not efficient so it can only be used for windbg. It seems that
cpu_interrupt does not work while CPU load is high depending on a guest OS.

Binary.
http://www.h6.dion.ne.jp/~kazuw/qemu-win/qemu-0.8.2-windbg.zip
Patch.
http://www.h7.dion.ne.jp/~qemu-win/download/qemu-20060730-windbg.patch

Regards,
Kazu