Re: CAC problem between RTEMS and vxWorks

[Benjamin Franksen <benjamin.franksen@helmholtz-berlin.de>]

Am Freitag, 28. September 2012, 20:17:01 schrieb Wesley Moore:
> Back to try to wrap this up...  Just added a timeout loop to watch
> pvConnected() and it shows I only needed a small delay after pvAssign().

Good. However...

I strongly discourage using delays in such cases. This is unreliable, network-
related problems could cause the connect to take longer than what you
measured, even if you add a sizeable margin to account for such variations. It
is much better to break up the action into more states, i.e. after pvAssign
transition to another state and use

        when(pvConnected(var)) {
                pvPut(var);
                ... more actions...
        } state ...

If you are concerned about this covering up problems such as over-long
connection times, add a timeout clause

        when(delay(connectShouldNotTakeLongerThanThis)) {
                printf("connect timeout for variable x\n");
        } state ...

Cheers
--
Ben Franksen
()  ascii ribbon campaign - against html e-mail
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> Haven't seen any adverse effects on the RTEMS client using this dynamic
> reconnection scheme.  By doing this, I've reduced the number of monitored
> PVs in the legacy sequencers from 8032 to 36.
>
> When rebooting the RTEMS client (running the sequencers), reconnection to
> the VxWorks server has taken as long as 4min.  I've added a stringout to
> give me the status of the connections.  VxWorks cleans up the dead sockets
> eventually, so this shouldn't be an issue during normal operations.
>
> Thanks for all the time you have put into sorting out the various issues.
> Let me know if there's anything further you want to test.
>
> Wesley
>
> ----- Original Message -----
>
> > From: "Benjamin Franksen" <benjamin.franksen@helmholtz-berlin.de>
> > To: tech-talk@aps.anl.gov
> > Sent: Thursday, September 27, 2012 3:34:10 PM
> > Subject: Re: CAC problem between RTEMS and vxWorks
> >
> > Am Dienstag, 25. September 2012, 23:10:28 schrieb Benjamin Franksen:
> > > I think we are closing in. I should have looked at the program Wes
> > > sent to
> > > me, which I did not at first. I did now and it is obvious (to me)
> > > now that
> > > it cannot work as expected. Specifically, doing
> > >
> > >         pvAssign(vidOutputStat, pvName);
> > >         ...
> > >         pvPut(vidOutputSel);
> >
> > Sorry, cut'n'paste error. I mean this part of your program (quoted
> >
> > literally):
> >                         printf("pvAssign Status:  %d\n",
> >
> >                                 pvAssign(vidOutputStat, pvName));
> >
> >                         pvGet(vwrName[ii]);
> >
> > /*                        strcpy(vidOutputStat, vwrName[ii]);*/
> >
> >                         sprintf(vidOutputStat, "%s", vwrName[ii]);
> >                         printf("pvPut Status:     %d\n",
> >
> >                                 pvPut(vidOutputStat));
> >
> > where you first
> >
> >         pvAssign(vidOutputStat, pvName)
> >
> > and then almost immediately afterwards (i.e. w/o waiting for the PV
> > to be
> > connected)
> >
> >         pvPut(vidOutputStat)
> >
> > Cheers
> > --
> > Ben Franksen
> > ()  ascii ribbon campaign - against html e-mail
> > /\  www.asciiribbon.org   - against proprietary attachments
> >
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________________________________

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.

Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. Vorsitzende Dr. Beatrix Vierkorn-Rudolph
Geschäftsführung: Prof. Dr. Anke Rita Kaysser-Pyzalla, Thomas Frederking

Sitz Berlin, AG Charlottenburg, 89 HRB 5583

Postadresse:
Hahn-Meitner-Platz 1
D-14109 Berlin

http://www.helmholtz-berlin.de