Il 28/08/2013 11:07, Erik Rull ha scritto: >>> It could be a real difference, actually. An unexpectedly fast disk >>> might screw a sloppy driver. IIRC you're not the first person reporting >>> it. Stefan, do you think using block throttling could fix it (with some >>> trial and error)? >> >> That might work. You could start with something like -drive ...,iops=20 >> and then disable the limit from the QEMU monitor once the guest OS is >> booting (block_set_io_throttle virtio0 0 0 0 0 0 0). >> >> It would be easier to try -drive ...,cache=writethrough and -win2k-hack >> first as Anthony suggests. >> >> Stefan > > Thanks. > I tried that, but when should I reset the throttle?
Never. The bug will be there through the whole execution of the guest. > When I reset it some seconds > after the BIOS screen disappeared same result as without throttling. When I > keep > it, Windows still reboots, the cycle just takes longer (half an hour), but the > progress seems to be the same as without throttle. On second thought that is expected. Until throttling kicks in, I/O will complete just as fast as without throttling. Maybe limiting the number of bytes per second instead of I/O ops would be better. Can you try -drive ...,bps=1048576 (possibly higher or lower numbers too)? And maybe Benoit's new algorithm could help too. Benoit, do you have a tree for Erik to try? Paolo
