Experimental Physics and
Industrial Control System

Am Freitag, 1. Juli 2011, um 23:22:44 schrieb Allison, Stephanie:
> Do you activate more than a few programs using the same sequence on one
> soft IOC?  I had a similar problem last year when moving some state
> programs from an RTEMS IOC to a linux IOC and found that putting a delay
> between activations helped:
> 
> ...
> seq(&psControl,"ps=GTL-ALPHA,limit=Des")
> epicsThreadSleep(1)
> seq(&psControl,"ps=GTL-Q1F,limit=Des")
> epicsThreadSleep(1)
> seq(&psControl,"ps=GTL-Q2D,limit=Des")
> ...
> 
> I never got a chance to debug further.  Probably something specific to my
> set up but your symptoms are the same.

Interesting. This confirms my suspicion that this might be a race condition. 
There is certain state that is shared between multiple instances of the same 
program (mostly during startup) which has not been properly protected against 
concurrent access in the 2.0.x series. These parts have been completely re-
engineered in what will become 2.1.0, so hopefully these delays (and similar 
ad-hoc work-arounds) will no longer be necessary.

Cheers
Ben

References:

SNL seq-2.0.13 on Linux 64 bits: not all monitored PVs receive their first monitor event Utzel Nadine

RE: SNL seq-2.0.13 on Linux 64 bits: not all monitored PVs receive their first monitor event Allison, Stephanie

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