[libvirt-users] [Qemu-devel] Adjust disk image migration (NBD)
Paolo Bonzini
pbonzini at redhat.com
Mon Feb 24 22:26:28 UTC 2014
> Thanks for raising this.
>
> I noticed that mirror_run() does not throttle the first loop where it
> populates the dirty bitmap using bdrv_is_allocated_above().
This is on purpose. Does it causes a noticeable stall in the guest?
> The main
> copy loop does take the speed limit into account but perhaps that's
> broken too.
Yeah, it looks broken. Each iteration of the loop can write much more
than sectors_per_chunk sectors, but here:
if (s->common.speed) {
delay_ns = ratelimit_calculate_delay(&s->limit, sectors_per_chunk);
} else {
delay_ns = 0;
}
the second argument is fixed. :/
Paolo
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