Experimental Physics and
Industrial Control System

Hinko Kocevar <[email protected]> · Thu, 26 May 2011 11:05:55 +0200

Hi all,

We are running EPICS 3.14.10 on ARM based system. Our device driver is

using asyn driver.

There are several records that are processed on I/O intr SCAN. Sometimes

the I/O rate is quite high and the system load (CPU) goes over the top,

with high (> 3.0) loadavg. When this happens IOC is sluggish to respond

to any CA requests.

Even if we manage to 'disable' the processing inside the device driver

(in terms that no new data is written to record buffers, I/O intr

SCANing still active), it takes quite some time to process all the

pending requests already in the ring buffers for the corresponding record.

Only then can we successfully use the CA to set/get any other PV on the

IOC, and not worry about the delayed response and/or timeouts.

Is there a way to tell IOC or a PV record to forget the pending

events/requests in its ring buffer (eg. some kind of flush)?

This way we could be sure that the IOC will be responding in timely

fashion, when we try to access some PV, and avoid waiting for the ring

buffer to empty by itself..

Has anyone dealt with similar situation?

Any comments and suggestions are welcomed!

Thank you,
Hinko

--
Hinko Kocevar
Technical support software engineer
Instrumentation Technologies
Velika pot 22, SI-5250 Solkan - Slovenia
T:+386 5 3352600, F:+386 5 3352601
mailto: [email protected]

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System