Experimental Physics and
Industrial Control System

"Angelic Ebbers" <[email protected]> · Thu, 21 Aug 2008 17:15:42 -1000

Hi,

We have a few older instruments which are still using EPICS 3.12.
Upgrading them is in progress, but is difficult due to old hardware.
One particular system is very unstable due to both high cpu loads and
high channel access traffic.  This system frequently looses channel
access communication when both cpu load an CA load coincide.  We've
decided to install a channel access gateway in an attempt to reduce the
channel access load on the IOC until the upgrade is complete.

I'm currently testing a PV Gateway Version 2.0.2.1 built on epics 3.14.6
, running on a solaris system.  I've set up the gateway as an Alias
gateway, moving the existing IOC to a different top-level name.  This
allows the gateway to handle the heavy external CA load.  Everything
appears to be working properly with clients like our Channel Archiver,
cagets, status displays communication with other IOCs.  Problems begin
when we try to use dm screen to control the instrument.  The dm screens
are accessing the IOC using the original top level names, so they are
being aliased though the gateway.  The dm screens appear to work fine
... changing inputs, modes etc on records, however, when a directive is
written to trigger a record to process, the command doesn't go through
and the gateway appears to hang ... (all new dm screens have no channel
info and after a while, existing screens also go white).  This happens
even when I build the screens under EPICS 3.14 ... so I'm concluding
that the problem is on the IOC side.  I can control the records using
caputs from any machine without any problems ... only the dm screens
seem to fail.  When record processing is triggered externally, the dm
screens currectly show the current status.

In order to rule out Access Security, I've set up the gateway to give
full access to default and all connections are default:
GATEWAY.access:

ASG(DEFAULT) {
   RULE(1,READ)
   RULE(1,WRITE)
}

GATEWAY.pvlist:
EVALUATION ORDER ALLOW, DENY

ao:.*            ALLOW 
ao:\(.*\)        ALIAS aog:\1 
aogate:.*        ALLOW 

# Convert old Gateway internal process variable names
aogate\.\(.*\)            ALIAS     aogate:\1 
aogate\.\(.*\)Flag        ALIAS     aogate:\1Flag 
aogate\.alive             ALIAS     aogate:connected
aogate\.postEventRate     ALIAS     aogate:clientPostRate

Has anybody seen this before?  Any suggestion?

Thanks
Angelic Ebbers
Gemini Observatory

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System