From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH v2 12/16] libxl: get and set soft affinity Date: Fri, 15 Nov 2013 18:29:17 +0100 Message-ID: <1384536557.3896.151.camel@Abyss> References: <20131113190852.18086.5437.stgit@Solace> <20131113191250.18086.1220.stgit@Solace> <21124.59400.960708.501641@mariner.uk.xensource.com> <5284F272.5070302@eu.citrix.com> <21124.63867.762364.416870@mariner.uk.xensource.com> <52860D6A.30901@eu.citrix.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8262756433325838558==" Return-path: In-Reply-To: <52860D6A.30901@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: Marcus Granado , Keir Fraser , Ian Campbell , Li Yechen , Andrew Cooper , Juergen Gross , Ian Jackson , xen-devel@lists.xen.org, Jan Beulich , Justin Weaver , Matt Wilson , Elena Ufimtseva List-Id: xen-devel@lists.xenproject.org --===============8262756433325838558== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-FxptaINtdboD1ZHLfQ3+" --=-FxptaINtdboD1ZHLfQ3+ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On ven, 2013-11-15 at 12:02 +0000, George Dunlap wrote: > On 14/11/13 16:25, Ian Jackson wrote: > > Maybe it is a bug that it doesn't do anything. I think it depends how > > we expect people to use this. If a caller sets the hard affinities > > and then changes the cpupool, are they supposed to always then set the > > hard affinities again to a new suitable value ? >=20 > Well in fact, as far as I can tell, it *does* do something. When moving= =20 > a vcpu to a new pool, it unconditionally calls=20 > cpumask_setall(v->cpu_affinity) for each vcpu, which will effectively=20 > erase the hard affinity. (xen/common/schedule.c:sched_move_domain()). >=20 > And, when unplugging cpus, if it unplugs the last cpu a vcpu can run on,= =20 > it also resets the affinity to "all". >=20 Right. But this all happens in hypervisor level and, personally, I think it's just fine. The point here is how we should behave and what kind of interface we should have/add at the libxl level. My opinion here is that, while it is ok to have calls that deals with both hard and soft affinity together, we should leave cpupool alone, as it is too different of both a concept and of an interface. Thanks and Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-FxptaINtdboD1ZHLfQ3+ 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 v1.4.15 (GNU/Linux) iEYEABECAAYFAlKGWe0ACgkQk4XaBE3IOsTFdwCeJhnfSCaSORjvSeri82zJbv5h 7+UAnitMKd7xKAkkXyT8KqTrOTJ2Qj9R =buW/ -----END PGP SIGNATURE----- --=-FxptaINtdboD1ZHLfQ3+-- --===============8262756433325838558== 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 --===============8262756433325838558==--