Re: [PATCH v3 1/7] libxl: get rid of the SEDF scheduler

[Dario Faggioli <dario.faggioli@citrix.com>]

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On Mon, 2015-07-06 at 16:40 +0100, George Dunlap wrote:
> On 07/06/2015 04:30 PM, Dario Faggioli wrote:
> > only the interface is left in place, for backward
> > compile-time compatibility, but every attempt to
> > use it would throw an error.
> > 
> > Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
> > Reviewed-by: George Dunlap <george.dunlap@eu.citrix.com>
> 
> This probably should have been dropped...
> 
> > Chenges from v2:
> >  - introduce and use ERROR_FEATURE_REMOVED, as requested
> >    during review;
> >  - mark the SEDF only parameter as deprecated in libxl_types.idl,
> >    as requested during review.
> 
> ...given these.  One question:
> 
Really? I'm basically only adding commentary, not changing (or adding,
or removing) a single line of code... I mean, the deprecation was
de-facto there already, since v1, it just was not stated explicitly
anywhere in that particular file.

That's why I didn't think a something like adding this comment would
call for removal of the tag.

Anyway, sorry for this. :-)

> > @@ -356,9 +357,13 @@ libxl_domain_sched_params = Struct("domain_sched_params",[
> >      ("weight",       integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_WEIGHT_DEFAULT'}),
> >      ("cap",          integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_CAP_DEFAULT'}),
> >      ("period",       integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_PERIOD_DEFAULT'}),
> > -    ("slice",        integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_SLICE_DEFAULT'}),
> > -    ("latency",      integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_LATENCY_DEFAULT'}),
> > -    ("extratime",    integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_EXTRATIME_DEFAULT'}),
> > +    # The following three parameters ('slice', 'latency' and 'extratime') are deprecated,
> > +    # and will have no effect if used, since the SEDF scheduler has been removed.
> > +    # Note that 'period' was an SDF parameter too, but it is still effective as it is
> > +    # now used (together with 'budget') by the RTDS scheduler.
> > +    ("slice",        integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_SLICE_DEFAULT'}),     # deprecated
> > +    ("latency",      integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_LATENCY_DEFAULT'}),   # deprecated
> > +    ("extratime",    integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_EXTRATIME_DEFAULT'}), # deprecated
> >      ("budget",       integer, {'init_val': 'LIBXL_DOMAIN_SCHED_PARAM_BUDGET_DEFAULT'}),
> 
> Since we're aiming for API compatibility rather than ABI compatibility,
> is it allowable to move 'budget' up above the comment, so that it's more
> obvious that it hasn't been deprecated?
> 
It's tool's people call, I guess. My opinion is that, yes, it should be
possible without any issue, and yes, I also would like the end result
better.

Thanks and Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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