From mboxrd@z Thu Jan  1 00:00:00 1970
From: Glauber Costa <glommer@redhat.com>
Subject: Re: migrate_set_downtime bug
Date: Wed, 7 Oct 2009 09:32:53 -0300
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Cc: Avi Kivity <avi@redhat.com>,
	Anthony Liguori <anthony@codemonkey.ws>,
	kvm <kvm@vger.kernel.org>
To: Dietmar Maurer <dietmar@proxmox.com>
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On Wed, Oct 07, 2009 at 06:42:48AM +0200, Dietmar Maurer wrote:
> > > The default downtime is set to 30ms. This value triggers the
> > convergence problem quite often. Maybe a longer default is more
> > reasonable.
> > What do you feel about 100 ms?
> 
> What is the reasoning behind such short downtimes? Are there any application that will fail with longer downtimes (let say 1s)?
> 
> Note: on a 1Gbit/s net you can transfer only 10MB within 100ms

which accounts for more than 2 thousand pages, which sounds like enough for a first pass to me. For the default case,
It is hard to imagine an application dirtying more than 2k pages per-iteration