From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:51370) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWoul-0007pI-6L for qemu-devel@nongnu.org; Tue, 22 May 2012 09:14:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SWoug-0006za-78 for qemu-devel@nongnu.org; Tue, 22 May 2012 09:14:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60859) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SWouf-0006zP-Qy for qemu-devel@nongnu.org; Tue, 22 May 2012 09:14:10 -0400 Message-ID: <4FBB9110.2020808@redhat.com> Date: Tue, 22 May 2012 07:13:52 -0600 From: Eric Blake MIME-Version: 1.0 References: <1337691425-6022-1-git-send-email-owasserm@redhat.com> <1337691425-6022-4-git-send-email-owasserm@redhat.com> In-Reply-To: <1337691425-6022-4-git-send-email-owasserm@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig5E0226C5B83C6E812B498F93" Subject: Re: [Qemu-devel] [PATCH v11 3/9] Add XBZRLE documentation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Orit Wasserman Cc: peter.maydell@linaro.org, aliguori@us.ibm.com, quintela@redhat.com, stefanha@gmail.com, qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com, blauwirbel@gmail.com, avi@redhat.com, pbonzini@redhat.com, chegu_vinod@hp.com This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig5E0226C5B83C6E812B498F93 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 05/22/2012 06:56 AM, Orit Wasserman wrote: > Signed-off-by: Orit Wasserman > --- > docs/xbzrle.txt | 114 +++++++++++++++++++++++++++++++++++++++++++++++= ++++++++ > 1 files changed, 114 insertions(+), 0 deletions(-) > create mode 100644 docs/xbzrle.txt >=20 > diff --git a/docs/xbzrle.txt b/docs/xbzrle.txt > new file mode 100644 > index 0000000..16950d5 > --- /dev/null > +++ b/docs/xbzrle.txt > @@ -0,0 +1,114 @@ > +XBZRLE (Xor Based Zero Run Length Encoding) > +=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 > + > +Using XBZRLE (Xor Based Zero Run Length Encoding) allows for the reduc= tion of VM > +downtime and the total live-migration time of Virtual machines. > +It is particularly useful for virtual machines running memory write in= tensive > +workloads that are typical of large enterprise applications such as SA= P ERP > +Systems, and generally speaking for any application that uses a sparse= memory > +update pattern. > + > +Instead of sending the changed guest memory page this solution will se= nd a > +compressed version of the updates, thus reducing the amount of data se= nt during > +live migration. > +In order to be able to calculate the update, the previous memory pages= needed to s/needed/need/ > +be stored. Those pages are stored in a dedicated cache (hash table) an= d are s/stored./stored on the source./ > +Format > +=3D=3D=3D=3D=3D=3D=3D > + > +The compression format uses the zero value, where zero represents an u= nchanged > +value. s/uses the zero value/performs an XOR between the previous and current content of the page/ --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enig5E0226C5B83C6E812B498F93 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJPu5EQAAoJEKeha0olJ0NqyzoH/2MRNy5duBLu16HwDE9GM9P7 E4YDmiKsGX9QaqA34yog0nRC1scXtnjaadni6f2ZaBXV9B4ZPSZHA1hs/vPMAXjv gungPntJbN/4xNHDo7FyHwkcmaFVm47FEyyJ8s6paGfq8AqN6SbgT97EqmIMAmg2 Lbe3pTRyUH2u0uhCFQJF1xs4MpRVHAjP6nnJp+GZO1RZIeqSqziU999ojCHzGEIq LNkc/TPV7frCgOceo3vRFblhDBLXhjoF9NQN7lae7i2v6VxbKSpXmiKM78uQbiu1 rFV9ZUqJzlG8oM85cZHd6PLs+tJ+gJGFf7yi+43rbEhMLbeel6YhSgXl4lxKlgE= =yPqB -----END PGP SIGNATURE----- --------------enig5E0226C5B83C6E812B498F93--