Experimental Physics and
Industrial Control System

"Leicester, PJ \(Pete\)" <[email protected]> · Mon, 22 Aug 2005 12:49:40 +0100

No responses to my last email regarding large transfers through the
Gateway. I'd still like to get an idea of any potential problems in this
area so two questions:-

1) Is anyone doing large transfers through the gateway?
2) Has anyone tried large transfers and had problems?

Pete Leicester
Diamond Light Source Ltd.
Tel: 44 1235 778478

-----Original Message-----
From: Leicester, PJ (Pete) [mailto:[email protected]] 
Sent: 01 August 2005 10:57
To: [email protected]
Subject: Gateway and EPICS_CA_MAX_ARRAY_BYTES

I have been trying to get a gateway running doing large transfers
(EPICS_CA_MAX_ARRAY_BYTES=3000000) but I am seeing performance problems.

I can get everything to work but only by restarting the gateway AFTER I
have booted the IOC and started the EDM client. In the working state the
Gateway clientEventRate/clientPostRate/serverEventRate/serverPostRate
are all at around 60Hz. If I then close the EDM client and restart it
the Gateway runs very slow, the event rate drops down to about 6 Hz
occasionally rising to 16Hz but it never recovers. If I reboot the
gateway without touching the IOC or EDM client I get back to the 60Hz
rate. At all times the event to post rates are much the same (i.e.
clientEventRate=clientPostRate and  serverEventRate=serverPostRate). I
only have 40 PV's in total, the gateway appears lightly loaded even when
running slow (loopRate=260,cpuFraction=0.06,load=0.05).

My test setup is as follows:
Client EDM screen running on linux/epics 3.14.6
Gateway version 2.0.0.0Beta18 running on linux/EPICS 3.14.7 cvs snapshot
taken on 14th April 05. IOC running Vxworks/EPICS 3.14.6 All have
EPICS_CA_MAX_ARRAY_BYTES=3000000 and the Client and Gateway both have
EPICS_CA_AUTO_ADDRESS_LIST=NO.

My questions are:-
1) Has anyone got large transfers to work reliably? 
2) Should I be able to do large transfers with this setup? 
3) Has anyone seen this problem before and what is going on when the
gateway is running slow?

Pete Leicester
Diamond Light Source Ltd.
Tel: 44 1235 778478

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System