Experimental Physics and
Industrial Control System

Matthias Clausen <[email protected]> · Thu, 05 Aug 2010 08:37:47 +0200

Hi Gary.
Gary Carr wrote:

Does anyone have any performance data for caPutLogging? How does it
effect the IOC? How many logs can you do per second?

Gongfa Liu ran several tests while he was working at DESY.
I do not recall any statistical performance numbers he took.
Maybe he can comment on this.
In any case there's a built in queue which performs like a throttle.

I would be interested in any data for the old system (3.13.4), and the
new 3.14 caPutLogger.

There are several improvements in 3.14 which will not affect the CPU
load but rather the correct behavior when you keep track of put to the
same channel within a given time (keeping track of the min, max values
when e.g. writing to a channel with a slider). These changes still need
to be retrofitted into the current release.
The CPU load was never an issue and so we did neither measure nor change
anything in this respect.

Beware: If you are writing regularly from a program outside the IOC
through channel access to the IOC - this will trigger caPutLogging :-(
In our case we are forwarding puLog, snlLog, sysLog, alarms ... through
logMessage processes to our JMS based logging system.
Cheers
Matthias

--
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Matthias Clausen                         Cryogenic Controls Group(MKS-2)
phone:  +49-40-8998-3256                Deutsches Elektronen Synchrotron
fax:    +49-40-8994-3256                                    Notkestr. 85
e-mail: [email protected]                           22607 Hamburg
WWW-MKS2.desy.de                                                 Germany
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System