Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Fri, 23 Aug 2013 15:14:54 +0000

Hi Dirk,

I think that it would be better if streamDevice did not do connection management at all.  If the user has configured the port with autoconnect=1 then asyn should handle the connection management fine.  If the user has set autoconnect=0, then presumably they have done that for a reason.  If streamDevice connects when autoconnect=0 it is doing something the user has asked not to be done.

If I understand correctly, in connectToAsynPort you are attempting to connect if the port is disconnected, even if autoconnect=0.

Mark

________________________________________
From: [email protected] [[email protected]] on behalf of Dirk Zimoch [[email protected]]
Sent: Friday, August 23, 2013 2:58 AM
To: [email protected]
Subject: Re: Asyn AutoConnect  and stream device on a soft IOC

I suspect that the reason is that many records fail talking to the
device in short time. Each one finds the device disconnected, tries to
connect and fails.

Mark, Should I better not call connect() when the device has
auto-connect on?

Dirk

On 23.08.2013 00:35, Mark Rivers wrote:
> I don't think the problem is necessarily with asyn.  The problem may be with StreamDevice, which appears to do its own connection management.
>
> As far as I can follow the flow in stream device:
>
> lockRequest will queue a request with asynQueuePriorityConnect if it finds the port is disconnected
>
> That results in a call to lockHander, which in turns calls connectToAsynPort
>
> connectToAsynPort queries whether the port is connected, and if not it calls pasynCommon->connect, which does the actual IP connection attempt.
>
> So each time lockRequest is called, which I think is for each streamDevice I/O operation, it can result in a connection attempt.
>
> Mark
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Scott Baily
> Sent: Thursday, August 22, 2013 4:34 PM
> To: [email protected]
> Subject: Asyn AutoConnect and stream device on a soft IOC
>
> We've been running a soft IOC that talked to a number of ethernet based
> devices. We've been using the auto-reconnect feature of asyn, and
> generally it works.  However we often have problems where a device is
> unreachable on the network, and apparently asyn will try to reconnect to
> it many times in rapid succession, the end result is that the load on
> one cpu core will reach 100%. At this point even if the device is
> reconnected to the network the IOC will not successfully reconnect.
> Has any one else had this problem, or no how to avoid it.
> Probably, I could turn off autoreconnect and have a record that requests
> reconnects at a specified maximum rate as needed. I'm wondering if
> there's some setting that I've missed that limits how quickly asyn will
> attempt to reconnect.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System