Re: Live migration locks up 3.2 guests in do_timer(ticks ~ 500000)

[Matt Mullins <mmullins+lkml@tuxags.com>]

On Mon, Sep 08, 2014 at 10:18:06AM +0200, Paolo Bonzini wrote:
> Il 08/09/2014 07:54, Matt Mullins ha scritto:
> > It also seems to happen reliably when the guest has been running for a while;
> > it's easily reproducible with guests that have been up ~1 day, and I've
> > reproduced it in VMs with an uptime of ~20 hours.  I haven't yet figured out a
> > lower-bound, which makes the testing cycle a little longer for me.
> > 
> > The guests that I reliably reproduce this on are Ubuntu 12.04 guests running
> > the current 3.2 kernel that Canonical distributes.  Recent Fedora kernels
> > (3.14+, IIRC) don't seem to busy-spin this way, though I haven't tested this
> > case exhaustively, and I haven't written down very good notes for the tests I
> > have done with Fedora.
> 
> What host are you running?

What information do you want that I missed in my first email?

> The hosts are dual-socket Nehalem Xeons (L5520), currently running Ubuntu
> 14.04 and the associated 3.13 kernel.  I had previously reproduced this with
> 12.04 running a raring-backport 3.11 kernel as well, but I (seemingly
> erroneously) assumed it may have been a qemu userspace discrepancy.

I implied, but didn't explicitly state: I don't remember this happening with
Ubuntu 12.04's 3.2 kernel running on the hosts.