"Computation error" status

Questions and Answers : Macintosh : "Computation error" status
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Eric Nylund
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Message 1682939 - Posted: 23 May 2015, 3:44:29 UTC

I have many SETI@home tasks with deadlines of July 14 or July 17 that indicate "Computation error". Processing continues normally for tasks with deadlines before July 14 with some July 14 and 17 in the queue.

What's so special about July 14 (other than Bastille Day) and/or July 17?

Why do these things always happen just before a holiday? After 40 years in the IT world I know the answer is, "Because". ;-{)}

Yosemite 10.10.3 with updates as of this posting date.
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Message 1683224 - Posted: 23 May 2015, 11:47:28 UTC - in response to Message 1682939.  

It's best to post this question over in Number Crunching

http://setiathome.berkeley.edu/forum_forum.php?id=10

This section of Seti doesn't get much traffic so question may go for long periods of time before getting answered.

TBar is probably the best to answer this question. He is very familiar with ATI graph cards and with Macs so he probably knows what the error in the stderr reports means.

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Message 1683369 - Posted: 23 May 2015, 17:43:28 UTC - in response to Message 1683224.  
Last modified: 23 May 2015, 17:43:38 UTC

You can as well:
SIGSEGV: segmentation violation

The messages about SIGPIPE: write on a pipe with no reader aren't too good either. I suspect it has to do with the Radeon HD4670 being now too old to be used for OpenCL. The HD4xx0 cards only had beta OpenCL support, real OpenCL 1.0 support requires a HD5xx0 or higher.

So the best short solution is to go to the project preferences, edit these and uncheck Use ATI GPU. Save changes with the button bottom of the page, next allow BOINC to contact the project. Also best to abort all setiathome_7.05_x86_64-apple-darwin__opencl_ati5zc_mac tasks. They won't run anyway.
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Eric Nylund
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Message 1683851 - Posted: 24 May 2015, 23:37:47 UTC

Many thanks to Ageless. After reading through some FAQs I'd say Ageless is spot on with the idea that my 4-year-old Mac's Radeon HD4670 is "too old". All of the failed WUs (more have occurred) do indeed indicate "v7 7.05 (opencl_ati5zc_mac)" in the Application column of BOINC Manager and I am aborting them as they occur .

I have not yet unchecked "Use ATI GPU" because I would like SETI to use the GPU if it can. All of the remaining WUs seem to be processing just fine. Does that mean that they are being processed by the CPU(s) only regardless of that checkbox status? Can SETI@home v7 7.00 detect specific GPU variants? It seems not but I don't want to waste a perfectly good processor by merely looking at the display screen. ;-{)}

Again, many thanks for the info.

Eric
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Message 1689729 - Posted: 10 Jun 2015, 9:59:18 UTC - in response to Message 1683851.  

The SETI@Home v7 7.00 application is a CPU-specific app. GPU-specific apps are a separate version; 7.05 for v7 workunits and 7.07 for AstroPulse. You can see all the different versions listed here.
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Questions and Answers : Macintosh : "Computation error" status


 
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