Re: [RFC PATCH v2 0/7] Repurpose SEDF Scheduler for Real-time Use

From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Ian Jackson <ian.jackson@eu.citrix.com>,
	Robert VanVossen <robert.vanvossen@dornerworks.com>,
	Xen-devel <xen-devel@lists.xen.org>,
	Nathan Studer <nate.studer@gmail.com>,
	Josh Whitehead <josh.whitehead@dornerworks.com>
Subject: Re: [RFC PATCH v2 0/7] Repurpose SEDF Scheduler for Real-time Use
Date: Fri, 11 Jul 2014 16:02:50 -0400	[thread overview]
Message-ID: <20140711200250.GN23257@laptop.dumpdata.com> (raw)
In-Reply-To: <1405054902.29306.224.camel@Solace>

> However, the biggest problem of SEDF is its poor support for SMP, and
> lack of capability for setting scheduling parameters on a per-VCPU
> basis, which this series (rightfully) does not address.
> Imagine if, after proper review and cleanups, the set of changes from
> this series goes in, and no other follow up series makes it by feature
> freeze, 4.5 will have:
>  - SCHED_SEDF deprecated, because it was lacking SMP support and support
>    for per-VCPU scheduling parameters
>  - SCHED_CBS, _lacking_ SMP support and support for per-VCPU scheduling 
>    parameters
> Not ideal. :-/

(With release manager hat on)

Actually I would think it is OK. In terms of X feature count at this
point of time (T) and on 4.5 feature freeze day (T-RC0) if the number of
features is greater or equal we are OK.

What is bad if the amount of features on T-RC0 is less than now (so say
X-1 features). That is not the case.