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

Subject: Re: file read and EPICS interaction problem
From: Andrew Johnson <anj@aps.anl.gov>
To: Erik Johansson <erikj@keck.hawaii.edu>
Cc: "'tech-talk@aps.anl.gov'" <tech-talk@aps.anl.gov>
Date: Mon, 07 Apr 2003 10:47:40 -0500
Erik Johansson wrote:

I have been experiencing problems when reading a somewhat large file (~670k) from an NFS-mounted disk on an EPICS IOC. When EPICS is running, the file load takes an incredibly long time, typically 20 seconds or so, but can also take almost a full minute. Something appears to be blocking so that the file IO cannot take place. The problem goes away if EPICS is not running (i.e, it works fine if EPICS is loaded but iocInit has not occurred).

I was going to suggest that you check your networking (run an ifShow on the IOC and look at the error counters) - we've had similar kinds of issues on PowerPC boards due to one end of the wire being initialized to Full Duplex and the other for Half Duplex, which appears to work but is unreliable and results in packet errors. VxWorks doesn't provide a way to check what the network interface PHY is set for although I have a suitable routine for the dec21x40end driver, but you may be able to check the other end of the wire - if you see runt packets that's the problem.


However your iocInit() comment may imply a different issue. Check the vxWorks tasks running, and make sure that tNetTask is at a higher priority than any EPICS or driver task. If it's not, the reason the fread is slow may be because the other task isn't giving the network a chance to run.

HTH,

- Andrew
--
There are 10 types of people in the world:
Those who understand binary, and those who don't.


References:
file read and EPICS interaction problem Erik Johansson

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