This sounds like the symptoms you'd experience with multiple functions
using the same event channel port.
How are you obtaining the ports you're using to communicate?
Are you using alloc_unbound ?
c.
On Fri, 2005-02-18 at 22:41, Xin Zhao wrote:
> Thanks for your advice. I tried rmb() and wmb() before I sent last email,
> they does not help.
>
> Actually I am running a single processor core. :( So it should not have
> any delay. But I still ran into the problem. Another interesting thing is
> that my working flow should be as follows:
>
> domU issue a request -> generate an irq at dom0 -> domU waits for reply->
> dom0 gets the request, processes it and reply -> domU wakes up by irq
> caused by notification event sent by dom0, gets the result -> DomU sends
> another request
>
> That means, if domU does not get the irq from dom0, it will not issue next
> request. Because of the problem of req_prod updates, dom0 failed to get
> the request and thus will not process it, not mention to reply. So dom0
> should not be able to receive next request or next irq.
>
> But the fact is that dom0 can still get irq even it failed to get last
> request. It appears that dom0 issues multiple irqs for one event. How
> could that happed?
>
> -x
>
>
> On Fri, 18 Feb 2005, Christopher Clark wrote:
>
> > Are you running this on a single processor core?
> >
> > If not, it sounds to me like a cache coherency issue - you'll need a
> > write memory barrier after writing to the req_prod. If you're using
> > the ring macros from io/ring.h this should be already taken care of
> > for you in the push macros.
> >
> > c.
> >
> >
> > On Fri, 18 Feb 2005 16:44:30 -0500 (EST), Xin Zhao
> > <zhaoxin@xxxxxxxxxxxxxx> wrote:
> > > I ran into the following problem:
> > >
> > > I setup a shared ring page and an event channel between two domains (dom0
> > > and one domU), DomU increases req_prod by one and notify the dom0 via the
> > > event channel, dom0 then check req_prod pointer and process the request in
> > > the shared ring. But I noticed that sometimes dom0 get the irq triggered
> > > by the notification event, but the req_prod remains the same. This
> > > situation only happened occasionally. Why? Because the req_prod is saved
> > > in the shared, mapped page, I suspect that there is a delay of updates
> > > between two domains. Is that true? If so, how to handle this problem?
> > >
> > > Your advice is highly appreciated!
> > >
> > > -x
> > >
> > > -------------------------------------------------------
> > > SF email is sponsored by - The IT Product Guide
> > > Read honest & candid reviews on hundreds of IT Products from real users.
> > > Discover which products truly live up to the hype. Start reading now.
> > > http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@xxxxxxxxxxxxxxxxxxxxx
> > > https://lists.sourceforge.net/lists/listinfo/xen-devel
> > >
> >
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel
|
Home