From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: [PATCH v1 3/4] libxl: add rt scheduler Date: Thu, 4 Sep 2014 17:25:00 +0200 Message-ID: <1409844300.2673.235.camel@Solace.lan> References: <1408921125-21470-1-git-send-email-mengxu@cis.upenn.edu> <1408921125-21470-4-git-send-email-mengxu@cis.upenn.edu> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============6764552393307708945==" Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Meng Xu Cc: Ian Campbell , Sisu Xi , Stefano Stabellini , George Dunlap , Ian Jackson , "xen-devel@lists.xen.org" , Meng Xu , Jan Beulich , Chao Wang , Chong Li , Dagaen Golomb List-Id: xen-devel@lists.xenproject.org --===============6764552393307708945== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-WCyUYjjDWKvkOTL4pFUb" --=-WCyUYjjDWKvkOTL4pFUb Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On gio, 2014-09-04 at 10:47 -0400, Meng Xu wrote: > 2014-09-04 10:27 GMT-04:00 George Dunlap > : > =20 > So the suggestion was this: For the moment, use the existing > libxl > interface on a per-domain basis. Internally, this will set > all vcpus > to the same values. This will allow us to check in a useable > version > of the scheduler for people to test and improve. Then for 4.6 > we can > start working on a suitable libxl interface for setting > per-vcpu > scheduling parameters. >=20 > I have a question as to the user interface. > For 4.5, we only allow users to set all vcpus to the same values (I'm > totally fine with it.);=20 > Right. > But how about the get function? When users issue the command "xl > sched-rt", how should we display the parameters of vcpus? We just give > the "period", "budget" and "#VCPU" for a domain? I'm fine with this > display for 4.5. >=20 xl builds on top of libxl. If, from libxl, setting and getting per-vcpu values won't be possible, so it will be for xl. I'd say printing just one set of params, the ones that applies to all the vcpus of the domain is fine for 4.5. So, from xl, you'll get something similar to this: # xl sched-credit Cpupool Pool-0: tslice=3D30ms ratelimit=3D1000us Name ID Weight Cap Domain-0 0 256 0 > However ,my concerns is: In 4.6, when we allow vcpus to have different > parameters and need to display every vcpu's parameters, how should we > display when users use command "xl sched-rt"? When vcpus have > different period and budget, we cannot display like what we did in 4.5 > then. :-( >=20 It is the libxl API that has stability constraints, not xl sub-commands output. Of course, it's not very nice to turn something completely upside down. But given the fact we're accepting the new scheduler as an experimental feature, and the fact that `xl sched-rt' will be a new command being introduced in 4.5, I don't think changing its output in 4.6 would be a problem. Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-WCyUYjjDWKvkOTL4pFUb 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 iEYEABECAAYFAlQIhEwACgkQk4XaBE3IOsTXTACeKdAmTReABsbKBp9GV/5uoSKV v7oAnRsMEJ3FT5GIO/EDhld4Fc2hM9iW =7vhX -----END PGP SIGNATURE----- --=-WCyUYjjDWKvkOTL4pFUb-- --===============6764552393307708945== 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 --===============6764552393307708945==--