From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH v2] credit: generalize __vcpu_has_soft_affinity() Date: Fri, 6 Mar 2015 11:12:35 +0000 Message-ID: <1425640326.12503.32.camel@citrix.com> References: <54F9672B0200007800066D4A@mail.emea.novell.com> <54F9792A.7030605@eu.citrix.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5832733112536444809==" Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1YTqBK-0000Fs-LO for xen-devel@lists.xenproject.org; Fri, 06 Mar 2015 11:12:38 +0000 In-Reply-To: <54F9792A.7030605@eu.citrix.com> Content-Language: en-US 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: "xen-devel@lists.xenproject.org" , "JBeulich@suse.com" List-Id: xen-devel@lists.xenproject.org --===============5832733112536444809== Content-Language: en-US Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-HdafbUQTRryMJle1TupS" --=-HdafbUQTRryMJle1TupS Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, 2015-03-06 at 09:53 +0000, George Dunlap wrote: > On 03/06/2015 07:36 AM, Jan Beulich wrote: > It looks like the comment above this line could use changing too; >=20 It probably does. > --- > Hard affinity balancing is always necessary and must never be skipped. > But soft affinity need only be considered when it has a functionally > different effect than other constraints (such as hard affinity, cpus > online, or cpupools). >=20 > Soft affinity only needs to be considered if: > * The cpus in the cpupool are not a subset of soft affinity > * The hard affinity is not a subset of soft affinity > * There is an overlap between the soft affinity and the mask which is > currently being considered. > --- The original comment was more aimed at trying to make as evident as possible to the reader why the occurrence of a particular combination of hard and soft affinity makes using the latter pointless (perhaps it was not that effective at that, but that's another story! :-D). So, if changing it, I'd go for something more 'high level'; something that helps the reader grasp more quickly what is the actual meaning of those _subsect() and _intersect() operations. Perhaps: --- Hard affinity balancing is always necessary and must never be skipped. Soft affinity balancing is only useful if it, potentially, makes a difference. In more details, there is no point checking soft affinity if: * there is no online pCPU in the domain's cpupool that is not in the soft affinity mask * there is no pCPU in the hard affinity mask that is not in the soft affinity mask * there is no overlapping between the soft affinity mask and the mask being considered (which, in most cases, is the hard affinity mask) --- Regards, Dario --=-HdafbUQTRryMJle1TupS 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 v2 iEYEABECAAYFAlT5i4YACgkQk4XaBE3IOsTspwCeKjdNa+qXhjUuW/M8IdetOJVp WTgAoIG6/br9Ha3d41blmcSEvcRb1KM+ =N8GC -----END PGP SIGNATURE----- --=-HdafbUQTRryMJle1TupS-- --===============5832733112536444809== 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 --===============5832733112536444809==--