Argonne National Laboratory

Experimental Physics and
Industrial Control System

2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  Index 2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020 
<== Date ==> <== Thread ==>

Subject: Re: EPICS base V4
From: Eric Norum <norume@aps.anl.gov>
To: Andrew Johnson <anj@aps.anl.gov>
Cc: Ned Arnold <nda@aps.anl.gov>, Benjamin Franksen <benjamin.franksen@bessy.de>, Marty Kraimer <mrk@aps.anl.gov>, Jeff Hill <johill@lanl.gov>, Ralph Lange <Ralph.Lange@bessy.de>, Bob Dalesio <bdalesio1@comcast.net>, Matej Sekoranja <matej.sekoranja@ijs.si>
Date: Fri, 25 Feb 2005 12:49:15 -0600

On Feb 25, 2005, at 11:25 AM, Andrew Johnson wrote:

Responding to these comments in the order they were made:

Ralph Lange wrote:
Does this imply that IOC load is evenly distributed? I.e. that records with the same scanPeriod period are processed in a "spread over time" manner rather than "en bloc" as in V3?

I suspect that's how it would behave, although I'm not 100% sure how we should be measuring the delay period - presumably measured from the start time of the previous record processing (i.e. we'd add another timestamp field in dbCommon to record the start of processing time, although we could just start the processing delay time from the *end* of the previous processing). If we do it that way then records of the same period would get spread out over time by the delays between their timer going off and actually getting processed.

I'd like to register a strong objection to this since it means that the 'sampling rate' of periodic record processing is no longer deterministic. I think that it is much more important that the long-term average rate of periodic record processing match the specified rate.

--
Eric Norum <norume@aps.anl.gov>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793



References:
Re: EPICS base V4: iocCore database Marty Kraimer
Re: EPICS base V4: iocCore database Andrew Johnson
Re: EPICS base V4: iocCore database: Booleans Benjamin Franksen
EPICS base V4 Marty Kraimer
Re: EPICS base V4 Andrew Johnson
Re: EPICS base V4 Ralph Lange
Re: EPICS base V4 Andrew Johnson

Navigate by Date:
Prev: Re: EPICS base V4 Andrew Johnson
Next: RE: dataAccess Jeff Hill
Index: 2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020 
Navigate by Thread:
Prev: Re: EPICS base V4 Andrew Johnson
Next: Re: EPICS base V4: iocCore database: registrar, special Benjamin Franksen
Index: 2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020 
ANJ, 02 Feb 2012 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·