From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mullins Subject: Re: Live migration locks up 3.2 guests in do_timer(ticks ~ 500000) Date: Mon, 8 Sep 2014 08:56:42 -0700 Message-ID: <20140908155642.GF23305@hydra.tuxags.com> References: <20140908055416.GE23305@hydra.tuxags.com> <540D663E.2070905@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: kvm@vger.kernel.org Return-path: Received: from hydra.tuxags.com ([64.13.172.54]:40931 "EHLO mail.tuxags.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753675AbaIHQEq (ORCPT ); Mon, 8 Sep 2014 12:04:46 -0400 Content-Disposition: inline In-Reply-To: <540D663E.2070905@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 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.