[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [libvirt-users] Adjust disk image migration (NBD)
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [libvirt-users] Adjust disk image migration (NBD) |
Date: |
Mon, 24 Feb 2014 17:26:28 -0500 (EST) |
> 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