Re: [Xen-devel] How to Stop scheduler

[Pankaj Parakh <me.pankajparakh@xxxxxxxxx>]

How can I schedule idle vcpu voluntarily without using schedule() ??
Is there any function for it already defined, or do I have to follow
some steps.. ??

On Wed, Nov 4, 2009 at 5:09 PM, George Dunlap
<George.Dunlap@xxxxxxxxxxxxx> wrote:
>
> On Wed, Nov 4, 2009 at 5:59 AM, Pankaj Parakh <me.pankajparakh@xxxxxxxxx> 
> wrote:
> > If I take domain_update_lock for  a domain, what will happen to its
> > interrupts for IO completions or any other type..??
> > And will it be scheduled if I hold that lock..??
>
> Have you looked at the interrupt delivery / IO completion path, or the
> scheduler path, to see if those are affected by the
> domain_update_lock()?
>
> Xen is a bit of a twisted web; sometimes you just have to follow a web
> of logic around to find out what you're looking for; then, once you've
> come to a conclusion, test it by writing some code.
>
> For the scheduling question, you might start with looking at vcpu_runnable().
>
> Peace,
>  -George
>
> >
> > On Wed, Nov 4, 2009 at 11:08 AM, Pankaj Parakh <me.pankajparakh@xxxxxxxxx>
> > wrote:
> >>
> >> So is that means there will be no interrupt loss, and also clock in
> >> the paused domain will be in right and expected time.. ??
> >>
> >> On Wed, Nov 4, 2009 at 12:41 AM, George Dunlap
> >> <george.dunlap@xxxxxxxxxxxxx> wrote:
> >> > If you call vcpu_pause(), it atomically increments a counter in the vcpu
> >> > struct.  While that counter is non-zero, the vcpu *will not* be
> >> > scheduled,
> >> > interrupts or no.  Interrupts will be delivered when it's scheduled
> >> > again.
> >> >
> >> > -George
> >> >
> >> > Pankaj Parakh wrote:
> >> >>
> >> >>  If I pause a vcpu/domain using those functions, say if a domain's I/O
> >> >> request over then its interrupt will raise and it can restart its
> >> >> scheduling rite..?? How this interrupts are/ can be queued so that
> >> >> when the vcpu is in pause state, it should nat change its state and
> >> >> when it come back to wait state, those interrupt will not be lost..
> >> >>
> >> >> On Tue, Nov 3, 2009 at 5:18 PM, George Dunlap
> >> >> <George.Dunlap@xxxxxxxxxxxxx> wrote:
> >> >>
> >> >>>
> >> >>> Do you mean that you want to stop one specific vcpu / domain from
> >> >>> being scheduled?
> >> >>>
> >> >>> If so, you're looking for the following functions:
> >> >>> vcpu_pause(), vcpu_unpause()
> >> >>> domain_pause(), domain_unpause().
> >> >>>
> >> >>> They're defined in xen/common/domain.c.
> >> >>>
> >> >>>  -George
> >> >>>
> >> >>>
> >> >>> On Mon, Nov 2, 2009 at 9:02 PM, Pankaj Parakh
> >> >>> <me.pankajparakh@xxxxxxxxx>
> >> >>> wrote:
> >> >>>
> >> >>>>
> >> >>>> Hi All,
> >> >>>>
> >> >>>> I am working on a project wherein I wanted to stop the scheduling
> >> >>>> activity in hypervisor through 'generic' part of scheduler, I have
> >> >>>> lil
> >> >>>> confusion as to what all things I need to mask/stop for disabling
> >> >>>> hypervisor to schedule any vcpu untill I want.
> >> >>>>
> >> >>>> Issues which I can think are about I/O waits or Zombie VCPUs. But how
> >> >>>> to tackle them... I dont know..
> >> >>>>
> >> >>>> I wanted to know what all responsibility the generic scheduler holds
> >> >>>> in hypervisor,
> >> >>>>
> >> >>>> Any type of info or pointer can be useful.
> >> >>>>
> >> >>>> Thanks
> >> >>>> Pankaj Parakh
> >> >>>>
> >> >>>> _______________________________________________
> >> >>>> Xen-devel mailing list
> >> >>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
> >> >>>> http://lists.xensource.com/xen-devel
> >> >>>>
> >> >>>>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Pankaj Parakh
> >
> >
> >
> > --
> > Pankaj Parakh
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> >
> >



--
Pankaj Parakh

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