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<== Date ==> <== Thread ==>

Subject: Re: flaky IOC problems at Jefferson Lab
From: [email protected]
To: [email protected]
Date: Tue, 07 Jan 97 13:28:42 -0500
>2) Raising the priority of the name resolution task above the scan
>   tasks gives me an uneasy feeling. An ioc should always give
>   highest priority to local affairs before it pays attention to
>   CA clients.

I disagree strongly.  If an operator can't bring up a control screen in a
timely fashion, the control system isn't working.  If a low priority
record isn't scanned for a few seconds, its no big deal (see LONG email
previously about scan priorities).  Again, we have many applications
split among multiple ioc's, so "local" doesn't address the whole problem.

Frankly, there is almost nothing in our EPICS databases which is truly
real time.  We do all our hard real time stuff in VxWorks tasks.

We'll try raising the priority of the CA TCP task; that just makes it 
much less likely to get into the hung state (which, of course, is good 
enough for now).  Thanks for this suggestion, I should have thought of
it myself.

>No matter what improvements are made to the CA connection algorithm,
>it will not solve the problem of an IOC having little or no idle time.

There's plenty of time if priorities are properly managed :)

Chip



Replies:
Re: flaky IOC problems at Jefferson Lab Marty Kraimer
References:
flaky IOC problems at Jefferson Lab Marty Kraimer

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