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Subject: Re: Stalled CA connection (IOC to CS-Studio archiver)
From: "Kasemir, Kay" <kasemirk@ornl.gov>
To: Ralph Lange <ralph.lange@gmx.de>, EPICS Core Talk <core-talk@aps.anl.gov>
Date: Fri, 25 Aug 2017 22:14:38 +0000
Hi:

>  The connection is very busy, at above 40K updates (double+status+timestamp) per second.
> We see congestion mode (events_off / events_on message pairs), i.e. the client is the bottleneck, while the IOC is still sort of relaxed, 
> sending out beacons like a  clockwork.
>At some point, the client gets so busy that it stops decoding the IOC's beacons. The reason for this moment of saturation is not clear. Garbage collection?

Our bottleneck has always been the RDB (Oracle, ..), so the ring buffers for the samples drop values when too many PV updates arrive.
Haven't seen PV updates as a problem.

Does the client have a high CPU load, or is it somehow stuck?
Can you attach jvisualvm to see what's going on:
Is there a lot of GC activity?
Are threads blocked a lot?
The "Sampler" for the CPU should show where it's spending most of the time.

-Kay

Replies:
Re: Stalled CA connection (IOC to CS-Studio archiver) Ralph Lange
References:
Stalled CA connection (IOC to CS-Studio archiver) Ralph Lange
Re: Stalled CA connection (IOC to CS-Studio archiver) Kasemir, Kay
Re: Stalled CA connection (IOC to CS-Studio archiver) Michael Davidsaver
Re: Stalled CA connection (IOC to CS-Studio archiver) Ralph Lange

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