From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35394) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YEgkR-0000hB-3j for qemu-devel@nongnu.org; Fri, 23 Jan 2015 11:06:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YEgkN-0007fF-1O for qemu-devel@nongnu.org; Fri, 23 Jan 2015 11:06:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42148) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YEgkM-0007es-Pv for qemu-devel@nongnu.org; Fri, 23 Jan 2015 11:06:10 -0500 Message-ID: <54C2716F.1060909@redhat.com> Date: Fri, 23 Jan 2015 09:06:07 -0700 From: Eric Blake MIME-Version: 1.0 References: <1418347746-15829-1-git-send-email-liang.z.li@intel.com> <1418347746-15829-13-git-send-email-liang.z.li@intel.com> <20150123134821.GL2370@work-vm> <54C26BE5.1060902@redhat.com> <20150123155957.GP2370@work-vm> In-Reply-To: <20150123155957.GP2370@work-vm> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="U1ber8ChMtwPFa5XqcX3UdFS0TaC5oErW" Subject: Re: [Qemu-devel] [v3 12/13] migration: Add command to set migration parameter List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: quintela@redhat.com, qemu-devel@nongnu.org, Liang Li , armbru@redhat.com, lcapitulino@redhat.com, yang.z.zhang@intel.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --U1ber8ChMtwPFa5XqcX3UdFS0TaC5oErW Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 01/23/2015 08:59 AM, Dr. David Alan Gilbert wrote: > * Eric Blake (eblake@redhat.com) wrote: >> On 01/23/2015 06:48 AM, Dr. David Alan Gilbert wrote: >>> * Liang Li (liang.z.li@intel.com) wrote: >>>> Add the qmp and hmp commands to tune the parameters used in live >>>> migration. >>> >>> If I understand correctly on the destination side we need to set the = number of >>> decompression threads very early on an incoming migration - I'm not >>> clear how early that needs to be - especially if you're using fd: so = it's >>> not waiting for a connect ? >>> >>> Eric: How would libvirt do that? >> >> Libvirt does some handshaking before starting migration. The source >> would advertise that "I'm capable of threaded migration; and plan to u= se >> X send and Y receive threads"; the destination would either reply that= >> threads are unsupported or set the receive thread count at that point,= >> then the source would know if it can enable threads and set the send >> thread count, before letting migration start. I don't see any problem= s >> with the current design of starting things up. >=20 > Patch 3 calls migrate_decompress_threads_create from process_incoming_m= igration_co, > if you're using fd based incoming migration then I think that gets call= ed > before libvirt would have a chance to connect to the monitor and > call the parameter setting to say how many threads it wants. > (A tcp incoming migration wouldn't have that problem because it > waits until the TCP accept before calling process_incoming_migration_co= ) Then it probably needs to be exposed through a command-line parameter, so that -incoming gains the ability to specify parameters as part of starting up qemu. --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --U1ber8ChMtwPFa5XqcX3UdFS0TaC5oErW Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJUwnFvAAoJEKeha0olJ0NqwgQH/j6WNE8PAPwQPwaTUWw1nm42 +J/vTBFjX5mQzT9JBod+JVaRRkGBmSXjzMXw8hyHi3FpMXbxAjHr+DIwSA5rwDyG aRob/OQl5S/xpZBdnFl0RcWtmtsP8ah1TvTHN0JhrZDKztYKvNeJ/5ADqO+09NaN EaM/n+rOFcbFdHZSFpdfVHbYiFFgco5wdQjO9+fpE+zwFGOxp/SjHDMEwO0Z1x6K W5W797kLohwNKuPmq9onFohQpOhbvUr8j4+hjxDI4uTWwYqFKFo2hYzkUnvng0sD ezp8K6hInrPrWfCF09PGaA+OjbehlBwtf2GmnXOaar0eAvqh71ohDsBuhPm5LBo= =TiTV -----END PGP SIGNATURE----- --U1ber8ChMtwPFa5XqcX3UdFS0TaC5oErW--