Event Channel Semantics

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* Event Channel Semantics
@ 2006-11-09 11:03 Julian Stecklina
  2006-11-09 15:34 ` Mark Williamson
  0 siblings, 1 reply; 4+ messages in thread
From: Julian Stecklina @ 2006-11-09 11:03 UTC (permalink / raw)
  To: xen-devel

Hello,

I am developing some userspace tools on Xen/Linux and have problems
regarding the semantics of /dev/linux/evtchn. The situation is as follows:

Suppose client A allocates an unbound port.
Client B connects to this via bind_interdomain.
Client A reads on /dev/linux/evtchn to see whether it has been notified.

If client B now notifies client A, the latter gets the correct port from
the call to read(). But all subsequent notifications get lost, and
client A just sits there blocking on read().

Is this intended? If not, where is the problem?

Regards,
Julian Stecklina

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Event Channel Semantics
  2006-11-09 11:03 Event Channel Semantics Julian Stecklina
@ 2006-11-09 15:34 ` Mark Williamson
  2006-11-16  1:06   ` Julian Stecklina
  0 siblings, 1 reply; 4+ messages in thread
From: Mark Williamson @ 2006-11-09 15:34 UTC (permalink / raw)
  To: xen-devel; +Cc: Julian Stecklina

> I am developing some userspace tools on Xen/Linux and have problems
> regarding the semantics of /dev/linux/evtchn. The situation is as follows:
>
> Suppose client A allocates an unbound port.
> Client B connects to this via bind_interdomain.
> Client A reads on /dev/linux/evtchn to see whether it has been notified.
>
> If client B now notifies client A, the latter gets the correct port from
> the call to read(). But all subsequent notifications get lost, and
> client A just sits there blocking on read().
>
> Is this intended? If not, where is the problem?

Are you clearing the event channel after receiving the first notification?

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Event Channel Semantics
  2006-11-09 15:34 ` Mark Williamson
@ 2006-11-16  1:06   ` Julian Stecklina
  2006-11-16  1:08     ` John Levon
  0 siblings, 1 reply; 4+ messages in thread
From: Julian Stecklina @ 2006-11-16  1:06 UTC (permalink / raw)
  To: xen-devel

Mark Williamson wrote:
> Are you clearing the event channel after receiving the first notification?

No, but is not obvious how to do that using the ioctls provided in
xen/linux/evtchn.h. IOCTL_EVTCHN_RESET seems to apply to all event channels.

Regards,
Julian

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Re: Event Channel Semantics
  2006-11-16  1:06   ` Julian Stecklina
@ 2006-11-16  1:08     ` John Levon
  0 siblings, 0 replies; 4+ messages in thread
From: John Levon @ 2006-11-16  1:08 UTC (permalink / raw)
  To: Julian Stecklina; +Cc: xen-devel

On Thu, Nov 16, 2006 at 02:06:34AM +0100, Julian Stecklina wrote:

> Mark Williamson wrote:
> > Are you clearing the event channel after receiving the first notification?
> 
> No, but is not obvious how to do that using the ioctls provided in
> xen/linux/evtchn.h. IOCTL_EVTCHN_RESET seems to apply to all event channels.

Write the event channel number to the device.

regards
john

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2006-11-16  1:08 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2006-11-09 11:03 Event Channel Semantics Julian Stecklina
2006-11-09 15:34 ` Mark Williamson
2006-11-16  1:06   ` Julian Stecklina
2006-11-16  1:08     ` John Levon

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