From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wei Liu <wei.liu2@citrix.com>
Subject: Re: [PATCH v5 for Xen 4.7 3/4] libxl: enable per-VCPU
 parameter settings for RTDS scheduler
Date: Tue, 9 Feb 2016 17:38:26 +0000
Message-ID: <20160209173826.GB18470@citrix.com>
References: <1454626244-5511-1-git-send-email-lichong659@gmail.com>
	<1454626244-5511-4-git-send-email-lichong659@gmail.com>
	<1455019237.3148.54.camel@citrix.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Return-path: <xen-devel-bounces@lists.xen.org>
Content-Disposition: inline
In-Reply-To: <1455019237.3148.54.camel@citrix.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Chong Li <chong.li@wustl.edu>, wei.liu2@citrix.com, Sisu Xi <xisisu@gmail.com>, george.dunlap@eu.citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, ian.campbell@eu.citrix.com, Meng Xu <mengxu@cis.upenn.edu>, Chong Li <lichong659@gmail.com>, dgolomb@seas.upenn.edu
List-Id: xen-devel@lists.xenproject.org

On Tue, Feb 09, 2016 at 01:00:37PM +0100, Dario Faggioli wrote:
[...]
> So, it looks to me that this function can be split in two. One would be
> the actual sched_rtds_vcpus_params_set(), and it will do what is being
> done above here.
> =

> The other one would be something like
> sched_rtds_vcpus_params_set_all(), and it will do what is being done
> below here.
> =

> About scinfo->num_vcpus, I think it would be fine for
> sched_rtds_vcpus_params_set() to enforce it being > 0, and erroring out
> if not.
> =

> On the other hand, in sched_rtds_vcpus_params_set_all(), since the
> semantic is "use this set of params for all vcpus", I think it would be
> fine to enforce scinfo->num_vcpus =3D=3D 1 (and maybe even
> scinfo.vcpus[0].vcpuid =3D=3D=A0LIBXL_SCHED_PARAM_VCPU_INDEX_DEFAULT).
> =

> =

> Now, for external callers (like xl, but also like any other toolstack
> wanting to build on top of libxl).
> =

> If you think a 'set all vcpus' function would be useufl (as it is
> probably the case), you can define a libxl API function called
> libxl_vcpus_params_set_all(), doing exactly the same thing that
> libxl_vcpus_params_set() is doing, but calling the
> sched_rtds_vcpus_params_set_all() internal function.
> =

> Chong, do you think this could work?
> Wei, what do you think of the resulting API?

Introducing a _all function sounds reasonable.

Wei.