From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH 04 of 11 v3] xen: sched_credit: let the scheduler know about node-affinity Date: Tue, 12 Mar 2013 17:20:58 +0100 Message-ID: <1363105258.3065.14.camel@Solace> References: <7b30913e753c4f0a2396.1359716474@Solace> <1363103867.32410.20.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4777163033509245547==" Return-path: In-Reply-To: <1363103867.32410.20.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: Marcus Granado , Dan Magenheimer , Matt Wilson , Anil Madhavapeddy , George Dunlap , Andrew Cooper , Juergen Gross , Ian Jackson , "xen-devel@lists.xen.org" , Jan Beulich , Daniel De Graaf List-Id: xen-devel@lists.xenproject.org --===============4777163033509245547== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-GEbrifDDb3syowpHvjo6" --=-GEbrifDDb3syowpHvjo6 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On mar, 2013-03-12 at 15:57 +0000, Ian Campbell wrote: > On Fri, 2013-02-01 at 11:01 +0000, Dario Faggioli wrote: > > As vcpu-affinity tells where VCPUs must run, node-affinity tells > > where they should or, better, prefer. >=20 > I cannot parse this sentence. Is the "or, better," redundant? >=20 I see... It's indeed redundant and it's a wording we sometime use in Italian, and translating it literally is not so much of a good idea, I guess. :-) How about "vcpu-affinity tells where VCPUs must run, node-affinity tells where they prefer to." > > While respecting vcpu-affinity > > remains mandatory, node-affinity is not that strict, it only expresses > > a preference, although honouring it is almost always true that will > > bring significant performances benefit >=20 > I can't parse this last bit either ("although...benefit"). If I drop the > "is almost always true that" it makes sense and I think expresses what > you meant.=20 > Right, my original form was missing something, but I like your version (i.e., removing the "is almost...that" part) better. I'll go for it. > And just a nit, it is "performance benefits". >=20 EhEh... George explained me this "performance" VS "performances" thing two times already, but so far I've always been able to always pick the _wrong_ one quite effectively! :-/ > > (especially as compared to > > not having any affinity at all). > >=20 > > This change modifies the VCPU load balancing algorithm (for the > > credit scheduler only), introducing a two steps logic. > > During the first step, we use the node-affinity mask. The aim is > > giving precedence to the CPUs where it is known to be preferable > > for the domain to run. If that fails in finding a valid PCPU, the > > node-affinity is just ignored and, in the second step, we fall > > back to using cpu-affinity only. >=20 > I think from previous paragraphs that you mean to say that the first > path takes into account node and vcpu affinity while the second only > vcpu affinity? The above reads as if it only uses the node affinity on > the first pass. > Yes, first pass uses the intersection of the two. I'll put the sentence in a way that makes this more evident. Thanks, Dario --=-GEbrifDDb3syowpHvjo6 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 v1.4.13 (GNU/Linux) iEYEABECAAYFAlE/VeoACgkQk4XaBE3IOsSoGQCdENbcHIXXXTHN2KjiMkuWo01N nacAnih/o1QHlyHTHA2R7AJiM9ZIhDbp =4FgQ -----END PGP SIGNATURE----- --=-GEbrifDDb3syowpHvjo6-- --===============4777163033509245547== 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 --===============4777163033509245547==--