From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH] xl: fix sedf parameters checking Date: Thu, 21 Jun 2012 12:54:37 +0200 Message-ID: <1340276077.4856.41.camel@Solace> References: <1340272422.21872.53.camel@zakaz.uk.xensource.com> <1340274407.4856.39.camel@Solace> <1340275231.21872.73.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============3614310485676241470==" Return-path: In-Reply-To: <1340275231.21872.73.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: Ian Jackson , Stefano Stabellini , "Keir (Xen.org)" , Jan Beulich , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org --===============3614310485676241470== Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-SFduc8iiz10kvwH0+QmM" --=-SFduc8iiz10kvwH0+QmM Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2012-06-21 at 11:40 +0100, Ian Campbell wrote: > > Also, I can't just set period to zero, as the call will fail also if I > > try to set weight=3D0, besides setting it internally in the scheduler c= ode > > (and that's why it is that that is returned when you ask for > > actual/default scheduling parameters). :-O > >=20 > > However, if you set extratime=3D1 (with period=3D0 and slice=3D0), what= ever > > weight you provide, will be zeroed by the hypervisor, even if you can't > > pass weight=3D0 yourself. >=20 > Ah, ok, so the key thing, which I think needs to be in the comment, is > that weight must be non-zero in this case but that the specific value is > irrelevant since it will be zeroed. >=20 Exactly! > I think it might be worth also mentioning in the comment what best > effort means in practice.I think it means a domain which can use extra > time but which has no actual period/slice/weight of its own (despite the > wrinkle about how you must supply weight). >=20 Ok. =20 > > Tricky eh? >=20 > Tricky isn't the half of it ;-) > :-) > > Both when I did this in the first place and now, I tried to look at wha= t > > main_sched_sedf() does and replicate that logic as much as I can, to > > make things easier to understand. The point here is we're being called > > by a different context/situation, but I maybe can give it another shot > > and see if I can quickly come up with something less mind blowing! :-P >=20 > I think actually with your explanations the current way seems to make > sense to me, some more detail in the comments should be sufficient I > think. Rewriting it again into something (even if it were less mind > blowing) would likely still mean another round of this sort of > conversation I expect ;-) >=20 Me too. I'll add those bits and resend then. 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) --=-SFduc8iiz10kvwH0+QmM 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/i/W0ACgkQk4XaBE3IOsSwQACaAgRq+549cD+KR+t6inq1ZfaH 6HgAoIZdQHWbczT3EU0oCm2nD+ZwURLM =139y -----END PGP SIGNATURE----- --=-SFduc8iiz10kvwH0+QmM-- --===============3614310485676241470== 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 --===============3614310485676241470==--