From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH 09 of 10 v3] libxl: have NUMA placement deal with cpupools Date: Fri, 06 Jul 2012 15:10:17 +0200 Message-ID: <1341580217.15708.27.camel@Abyss> References: <885e2f385601d6617905.1341418688@Solace> <4FF6DD1B.60106@eu.citrix.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8593921441927098251==" Return-path: In-Reply-To: <4FF6DD1B.60106@eu.citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: George Dunlap Cc: Andre Przywara , Ian Campbell , Stefano Stabellini , Juergen Gross , Ian Jackson , "xen-devel@lists.xen.org" , Roger Pau Monne List-Id: xen-devel@lists.xenproject.org --===============8593921441927098251== Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-IruOeYLTSbU/B9CbGk7L" --=-IruOeYLTSbU/B9CbGk7L Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2012-07-06 at 13:42 +0100, George Dunlap wrote:=20 > > libxl: have NUMA placement deal with cpupools > > > > In such a way that only the cpus belonging to the cpupool of the > > domain being placed are considered for the placement itself. > > > > This happens by filtering out all the nodes in which the cpupool has > > not any cpu from the placement candidates. After that -- as a cpu pooli= ng > > not necessarily happens at NUMA nodes boundaries -- we also make sure > > only the actual cpus that are part of the pool are considered when > > counting how much processors a placement candidate is able to provide. > > > > Signed-off-by: Dario Faggioli > > Acked-by: Ian Campbell > If I'm reading this right, the filtering won't prevent duplicate entries= =20 > returned from get_numa_candidates; is that right? I.e., suppose you=20 > have a 4-node system and you run "xl cpupool-numa-split" to get one pool= =20 > per node. Before this patch, your generator might return the following= =20 > sets containing node 0: > {0} > {0,1} > {0,2} > {0,3} > {0,1,2} > {0,1,3} > {0,1,2,3} > {0,2,3} >=20 > But now, if the domain is placed in a cpupool that has only numa node 0,= =20 > it will return 8 copies of {0}. Is that correct? >=20 It is. As the generation happens before cpupool are being considered at all. Point is, while the number of cores could be quite high (and continue to grow), the number of NUMA nodes in existing machines that such a case won't hurt that much. Anyway, you're definitely right, it would have been possible to do much better. Maybe, if we're cool with patch 8, we can jut skip this for now, and I'll resubmit a separate patch (where I'll deal with duplicates) like later or on Monday? Thanks and Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-IruOeYLTSbU/B9CbGk7L Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEABECAAYFAk/247kACgkQk4XaBE3IOsSMQACfbVNIhQakvKx+3vEsLKCLtgfj qaMAoJF9DJIDOhooLoIVvCyF5a14lc34 =/932 -----END PGP SIGNATURE----- --=-IruOeYLTSbU/B9CbGk7L-- --===============8593921441927098251== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============8593921441927098251==--