Re: [Xen-devel] [PATCH v7 15/17] vmx: VT-d posted-interrupt core logic handling

["Wu, Feng" <feng.wu@xxxxxxxxx>]

> -----Original Message-----
> From: Dario Faggioli [mailto:dario.faggioli@xxxxxxxxxx]
> Sent: Wednesday, September 23, 2015 4:00 PM
> To: Wu, Feng; George Dunlap
> Cc: xen-devel@xxxxxxxxxxxxx; Tian, Kevin; Keir Fraser; George Dunlap; Andrew
> Cooper; Jan Beulich
> Subject: Re: [Xen-devel] [PATCH v7 15/17] vmx: VT-d posted-interrupt core 
> logic
> handling
> >
> > I cannot think the bad effect of the spurious PI as well. I was just
> > a little
> > confused about we can do this and why we don't do this. Maybe
> > context_switch() is a critical path, if we can bear those spurious
> > PI,
> > it is not worth adding those logic in it at the cost of some
> > performance
> > lost during scheduling. Is this your concern?
> >
> The, however small, performance implications of even only checking
> whether the hooks should be invoked is certainly good to be avoided,
> especially, on non-PI enabled (and even more so on non-VMX) hardware.
> 
> However, what I think it is more important in this case, is that not
> having the hooks in context_switch() yields a better results from an
> architectural and code organization point of view.
> It makes both the context switch code, and the PI code, easier to
> understand and to maintain.

Good to know that, thanks for the explanation!

Thanks,
Feng

> 
> So, thanks to you 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)

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