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

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

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@xxxxxxxxxx>
> Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

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:

> @@ -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?

 -George


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