Re: [PATCH v1 1/4] xen: add real time scheduler rt

[Meng Xu <xumengpanda@gmail.com>]

[-- Attachment #1.1: Type: text/plain, Size: 2548 bytes --]

Hi George,


2014-09-03 10:15 GMT-04:00 George Dunlap <George.Dunlap@eu.citrix.com>:

> On Wed, Sep 3, 2014 at 3:11 PM, Meng Xu <xumengpanda@gmail.com> wrote:
> >> > diff --git a/xen/common/schedule.c b/xen/common/schedule.c
> >> > index 55503e0..7d2c6d1 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_def,
> >> >  };
> >> >
> >> >  static struct scheduler __read_mostly ops;
> >> > @@ -1090,7 +1091,8 @@ long sched_adjust(struct domain *d, struct
> >> > xen_domctl_scheduler_op *op)
> >> >
> >> >      if ( (op->sched_id != DOM2OP(d)->sched_id) ||
> >> >           ((op->cmd != XEN_DOMCTL_SCHEDOP_putinfo) &&
> >> > -          (op->cmd != XEN_DOMCTL_SCHEDOP_getinfo)) )
> >> > +          (op->cmd != XEN_DOMCTL_SCHEDOP_getinfo) &&
> >> > +          (op->cmd != XEN_DOMCTL_SCHEDOP_getnumvcpus)) )
> >>
> >> Why are you introducing this as a schedop?  Isn't this information
> >> already exposed in getdomaininfo?
> >
> >
> > I introduce XEN_DOMCTL_SCHEDOP_getnumvcpus as a schedop because we need
> to
> > know the number of vcpus a domain has when the tool stack wants to
> display
> > the parameters of EACH vcpu.
> >
> > I think the operation you meant in getdomaininfo is XEN_DOMCTL_max_vcpus
> (in
> > file xen/common/domctl.c)?
>
> No, the operation I had in mind was XEN_DOMCTL_getdomaininfo, which
> will give you nr_online_vcpus.
>
> > When the tool stack (command xl sched-rt -d domain) displays the
> parameters
> > of EACH vcpu, the tool stack will allocate an array whose size is
> > "sizeof(struct xen_domctl_sched_rt_params) * num_vcpus_of_this_domain"
> and
> > bounce this array to the hypervisor. After hypervisor fills out the
> > parameters of each vcpu, this array will be bounced out to tool stack to
> > display to users.
>
> Sure, there are lots of operations the toolstack wants that needs the
> number of vcpus, which is why it's already exposed with
> XEN_DOMCTL_getdomaininfo. :-)


​I see. Thank you very much for your information and advice! It's really
useful!

I will remove the ​
 XEN_DOMCTL_max_vcpus
​ from schedop and use ​
XEN_DOMCTL_getdomaininfo
​ to get the number of vcpus instead! :-)​

​Best,

Meng

-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania

[-- Attachment #1.2: Type: text/html, Size: 4084 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel