Re: [PATCH v2 1/4] xen: add real time scheduler rt

[George Dunlap <george.dunlap@eu.citrix.com>]

Interface comments on the first pass; I'll dig into the algorithm more 
on the second pass.

On 09/07/2014 08:40 PM, Meng Xu wrote:
> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
> index 73cc2ea..dc4f749 100644
> --- a/xen/common/schedule.c
> +++ b/xen/common/schedule.c
> @@ -69,6 +69,7 @@ static const struct scheduler *schedulers[] = {
>       &sched_credit_def,
>       &sched_credit2_def,
>       &sched_arinc653_def,
> +    &sched_rt_ds_def,

I think it would be nicer to leave the _ out of the middle -- just call 
this the "rtds" server (here and elsewhere).

>   };
>   
>   static struct scheduler __read_mostly ops;
> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
> index 69a8b44..11654d0 100644
> --- a/xen/include/public/domctl.h
> +++ b/xen/include/public/domctl.h
> @@ -347,6 +347,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_max_vcpus_t);
>   #define XEN_SCHEDULER_CREDIT   5
>   #define XEN_SCHEDULER_CREDIT2  6
>   #define XEN_SCHEDULER_ARINC653 7
> +#define XEN_SCHEDULER_RT_DS    8
> +
>   /* Set or get info? */
>   #define XEN_DOMCTL_SCHEDOP_putinfo 0
>   #define XEN_DOMCTL_SCHEDOP_getinfo 1
> @@ -368,6 +370,10 @@ struct xen_domctl_scheduler_op {
>           struct xen_domctl_sched_credit2 {
>               uint16_t weight;
>           } credit2;
> +        struct xen_domctl_sched_rt{
> +            uint32_t period;
> +            uint32_t budget;
> +        } rt;

I'm not sure if you meant to leave this as "rt" instead of "rtds", but I 
don't think we can assume that every other server is going to expose 
"period" and "budget": the sEDF scheduler had "slice" instead, for 
instance.  I would prefer this to be "xen_domctl_sched_rtds".

>       } u;
>   };
>   typedef struct xen_domctl_scheduler_op xen_domctl_scheduler_op_t;
> diff --git a/xen/include/public/trace.h b/xen/include/public/trace.h
> index cfcf4aa..87340c4 100644
> --- a/xen/include/public/trace.h
> +++ b/xen/include/public/trace.h
> @@ -77,6 +77,7 @@
>   #define TRC_SCHED_CSCHED2  1
>   #define TRC_SCHED_SEDF     2
>   #define TRC_SCHED_ARINC653 3
> +#define TRC_SCHED_RT       4

TRC_SCHED_RTDS

  -George