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

Subject: Re: Is it possible to have deterministic SoftIOC (R3.14.12) on Linux
From: David Kline <[email protected]>
To: Jimmy Johnson <[email protected]>
Cc: [email protected]
Date: Thu, 20 Jan 2011 09:01:45 -0600
fwiw:

i've been using a linux kernel real-time patch (2.6.19) in the ebricks
for quite sometime now, before it was rolled into mainline linux. after
installing the patch, about 3yrs ago, i remember measuring interrupt
latency against the 'out-of-the-box' with improvement, still wasn't
up to vxworks performance, however.

here's the link to where i got the patch as well as other info:
https://www.osadl.org/Realtime-Linux.projects-realtime-linux.0.html

/david

On 1/19/2011 6:17 PM, Jimmy Johnson wrote:

Hi

    I am planning on using a SoftIOC (R3.14.12) on Linux and will want to run a control loop (about 1000 lines of C code spread across a few custom records) deterministically at 100Hz. There will not be any other user applications, in addition to the IOC, running on the box. The hardware will most likely be a quad core or Core i7. My original plan was to use CentOS 5.5 which has a 2.6-18 kernel (quite old and with very few or none of the real-time work rolled into the mainline kernel) but I can go with the latest 2.6-37 kernel or a Real Time patched 2.6.33-RT30 if necessary.

 

Does anyone have any recent experience with something like this?

Is the preempt patch needed to support this?

Will EPICS support this out of the box or does it need to be tweaked in anyway?

I am assuming USE_POSIX_THREAD_PRIORITY_SCHEDULING should be set to YES?

 

Thanks

Jimmy

 


-- 

+--------------------------------------------------+
David M. Kline                    [email protected]
Argonne National Laboratory
Argonne IL, 60439                       630.252.8639

Advanced Photon Source, X-ray Science Division
Optics and Detectors Group
+--------------------------------------------------+
                  Detectors-R-Us
+--------------------------------------------------+ 

References:
Is it possible to have deterministic SoftIOC (R3.14.12) on Linux Jimmy Johnson

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