RE: ASYN - calling read after interrupt - fix :)

["Mark Rivers" <rivers@cars.uchicago.edu>]

> Thus your request for a configurable interrupt queue is somewhat 
> orthogonal to the topic although I agree that it is a good idea to 
> provide configurable sizes to interrupt handlers which use message 
> queues.

 
Eric is correct.  The queuing would all be done in the asyn driver, typically a message queue between the interrupt function and the thread that handles callbacks.  This is how my existing asyn interrupt drivers work.
 
Thus, if user-specified queue sizes are desired then the driver author would need to provide a way to configure that in the driver creation/configuration routine that is called from the startup script.
 
Mark
 

________________________________

From: tech-talk-bounces@aps.anl.gov on behalf of Eric Norum
Sent: Thu 10/11/2007 8:28 AM
To: benjamin.franksen@bessy.de
Cc: tech-talk@aps.anl.gov
Subject: Re: ASYN - calling read after interrupt - fix :)




On Oct 11, 2007, at 4:05 AM, Benjamin Franksen wrote:
>
>
> I agree with Mark and Eric. It may not be a problem in /most/ 
> situations if
> interrupt are lost. However, there may be cases where this is a 
> problem. I
> can imagine a card wants to acknowlege completion of a long runnign
> operation by issuing an interrupt. If multiple channels per card are
> involved, and each one gets its own completion interrupt, we'll have a
> problem indeed. Always remember Murphy's law ;-)
>
> BTW, if solution 2 gets implemented, I'd make sure the interrupt 
> queue size
> can be configured by the user.
>

I think that Mark's proposal 2 makes no changes to the way interrupt-
level code passes information to the ASYN callback thread.  If I 
understand properly, what he is proposing is to have the ASYN 
callback thread lock the record and process the record directly 
rather than having a scanIOrequest callback thread to do this work.

Thus your request for a configurable interrupt queue is somewhat 
orthogonal to the topic although I agree that it is a good idea to 
provide configurable sizes to interrupt handlers which use message 
queues.

--
Eric Norum <norume@aps.anl.gov>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793