RE: Asyn AutoConnect and stream device on a soft IOC

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

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: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Scott Baily
Sent: Thursday, August 22, 2013 4:34 PM
To: tech-talk@aps.anl.gov
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.
-- 
Scott Baily
AOT-IC, MS H820
Los Alamos National Laboratory
Los Alamos, NM 87545
ph: (505) 606-2260