From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH 08 of 10 v2] libxl: enable automatic placement of guests on NUMA nodes Date: Tue, 26 Jun 2012 18:25:08 +0200 Message-ID: <1340727908.9444.21.camel@Solace> References: <81f18379bb3d4d9397d1.1339779876@Solace> <1340278832.21872.112.camel@zakaz.uk.xensource.com> <1340296452.4856.87.camel@Solace> <1340360049.26083.82.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4293735062636114109==" Return-path: In-Reply-To: <1340360049.26083.82.camel@zakaz.uk.xensource.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: Ian Campbell Cc: Andre Przywara , Stefano Stabellini , George Dunlap , Juergen Gross , Ian Jackson , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org --===============4293735062636114109== Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-aw9n+rJ11gZMO2qhho7z" --=-aw9n+rJ11gZMO2qhho7z Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2012-06-22 at 11:14 +0100, Ian Campbell wrote: > > > > + /* Bring the best candidate in front of the list --> candidate= s[0] */ > > > > + if (nr_candidates > 1) > > > > + libxl__sort_numa_candidates(candidates, nr_candidates, num= a_cmpf); > > >=20 > > > Is the start up cost of libxl__sort_numa_candidates significant enoug= h > > > to make that if worthwhile? > > >=20 > > I'm not sure what you mean here, I'm afraid ... :-( >=20 > Is the cost of sorting the 1 element list so high it is worth avoiding. > Since the sort itself would be trivial the startup costs are what would > dominate. >=20 So, the answer is that I really don't know, as I'm using a library function for doing the actual work. I really do not expect for them to be that high, and I hence can remove the if() if you think it looks ugly. :-) > > > I'm not sure about this, if numa_place_domain fails for any reason wo= uld > > > we be not better off logging and continuing without placement? We > > > already do that explicitly in a couple of cases. > > >=20 > > Well, actually, if it "fails" in the sense it finds no candidates or > > does not manage in placing the domain, it returns 0, so we do right wha= t > > you're suggesting. I'm sure this is stated in some comment but I guess = I > > can repeat it here. If !rc, it means we stepped into some ERROR_FAIL or > > something, which I think has to be handled like this, hasn't it? >=20 > That makes sense. >=20 > > Perhaps I can also add some logging about "successfully failing", i.e., > > not getting into any error but not being able to place the domain. If > > yes, that will happen _inside_ numa_place_domain() rather than here. >=20 > Logging in that case seems wise in any case since it will have > performance implications I think. >=20 Ok, I'll log something out. 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) --=-aw9n+rJ11gZMO2qhho7z 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/p4mQACgkQk4XaBE3IOsQ3mQCfUw3Yp5pme8z6n5M+9bjMOuoq iKkAoJwY2zdWF9rpYfju0l6twL0kiVPj =0itV -----END PGP SIGNATURE----- --=-aw9n+rJ11gZMO2qhho7z-- --===============4293735062636114109== 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 --===============4293735062636114109==--