From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51876) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YEg6F-0005l3-EU for qemu-devel@nongnu.org; Fri, 23 Jan 2015 10:24:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YEg6C-0001NP-8e for qemu-devel@nongnu.org; Fri, 23 Jan 2015 10:24:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54391) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YEg6C-0001Ld-0Z for qemu-devel@nongnu.org; Fri, 23 Jan 2015 10:24:40 -0500 Message-ID: <54C267B3.4080204@redhat.com> Date: Fri, 23 Jan 2015 08:24:35 -0700 From: Eric Blake MIME-Version: 1.0 References: <1418347746-15829-1-git-send-email-liang.z.li@intel.com> <1418347746-15829-2-git-send-email-liang.z.li@intel.com> In-Reply-To: <1418347746-15829-2-git-send-email-liang.z.li@intel.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="lKgtoB5kJF4F3cJUL6Tk5a4U8wX8Jlxcu" Subject: Re: [Qemu-devel] [v3 01/13] docs: Add a doc about multiple thread compression List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Liang Li , qemu-devel@nongnu.org Cc: yang.z.zhang@intel.com, lcapitulino@redhat.com, armbru@redhat.com, dgilbert@redhat.com, quintela@redhat.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --lKgtoB5kJF4F3cJUL6Tk5a4U8wX8Jlxcu Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 12/11/2014 06:28 PM, Liang Li wrote: > Give some details about the multiple compression threads and > how to use it in live migration. >=20 > Signed-off-by: Liang Li > Signed-off-by: Yang Zhang > --- > docs/multi-thread-compression.txt | 141 ++++++++++++++++++++++++++++++= ++++++++ > 1 file changed, 141 insertions(+) > create mode 100644 docs/multi-thread-compression.txt >=20 > diff --git a/docs/multi-thread-compression.txt b/docs/multi-thread-comp= ression.txt > new file mode 100644 > index 0000000..3bbc641 > --- /dev/null > +++ b/docs/multi-thread-compression.txt > @@ -0,0 +1,141 @@ > +Use multiple thread (de)compression in live migration > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D > +Copyright (C) 2014 Intel Corporation You may want to include 2015 now. > +Introduction > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > +Instead of sending the guest memory directly, this solution will > +compress the ram page before sending; after receiving, the data will s/ram/RAM/ > +be decompressed. Using compression in live migration can help > +to reduce the data transferred about 60%, this is very useful when the= > +bandwidth is limited, and the migration time can also be reduced about= > +70% in a typical case. Of course, that's all dependent on memory having compressible contents. An application that reads /dev/hwrng into a large amount of memory will not be that compressible :) > + > +When to use the multiple thread compression in live migration > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D off-by-one on the divider length > +Usage > +=3D=3D=3D=3D=3D > +1. Verify both the source and destination QEMU are able > +to support the multiple thread compression migration: > + {qemu} info_migrate_capablilites s/capablilites/capabilities/ > + {qemu} ... compress: off ... > + > +2. Activate compression on the souce: s/souce/source/ > + {qemu} migrate_set_capability compress on > + > +3. Set the compression thread count on source: > + {qemu} migrate_set_paramter compress_threads 12 s/paramter/parameter/ > + > +The following is the default setting: s/is...setting/are...settings/ > + compress: off > + compress_threads: 8 > + decompress_threads: 2 > + compress_level: 1 (which means best speed) > + > +So, only the first two steps are required to use the multiple > +thread compression in migration. You can do more if the default > +setting is not appropriate. s/setting is/settings are/ --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --lKgtoB5kJF4F3cJUL6Tk5a4U8wX8Jlxcu 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/ iQEcBAEBCAAGBQJUwmezAAoJEKeha0olJ0NqVFYH/jQ6mzXOaBgpfqdYz7tQXyWA HZkdl0tUaDwYCfaMGDei+qbxmQAZvTROn9qaq0I3dIBT4dd4raLcP6T1Se8NBnCV gdyskXpD2A6SvmnjXZ0BcKF2FQ7P1AHYMRw/+NjA27JUAsZ8It8ufx4B/P/mQn7J 1LwEAJoFejsJbN9bDvgHEbU1Hvhd6irrv7Qf6Fu4fU8i6bn7bJZoLTL3jHuYbDEP PUI1Q+UhEF/SA1D2Ilr2r0kMEXQobMqtBjQ8PALPqnUXypP40r0tvfG/UzILmWUA kGkdjyb6FzzEl45qTMJm8LnHy/ArbGxVbLYSDfBHeYFyV7NM5/xEPbmLZWcqxvI= =XJnm -----END PGP SIGNATURE----- --lKgtoB5kJF4F3cJUL6Tk5a4U8wX8Jlxcu--