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Questions and Answers : Unix/Linux : Milkyway@Home says it's running a task on 4 CPUs, but it isn't.
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ProfileUnionJack

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Message 63233 - Posted: 15 Mar 2015, 11:34:37 UTC

If I suspend the task, another one starts in its place, also claiming to be running on 4 CPUs but also not. Meanwhile I have three cores at 1% load and three other projects waiting. I've seen the problem before; it seems I just have to sit and wait.

This is Gentoo Linux running on an Asus P7P55D motherboard and i5 CPU, 16 GB RAM, plenty of disc, nVidia Quadro FX580 graphics, no CUDA.

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Peter.
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alanb1951

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Message 63239 - Posted: 16 Mar 2015, 5:04:46 UTC - in response to Message 63233.  

Apparently, the initialization code for NBody doesn't lend itself to use of multiple threads, so until the initialization phase is completed it only uses one core. That is probably what you're seeing (and, if so, it's system-independent.)

For more information, see the "New Nbody version 1.48" thread in the News forum.

Hope this helps - Al.
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Message 63244 - Posted: 18 Mar 2015, 9:43:23 UTC - in response to Message 63239.  
Last modified: 18 Mar 2015, 10:34:32 UTC

That could be it, yes, but if so, it's taking an unexpectedly long time to initialise. Unexpected by me, that is. I'll watch it for a while.

Thanks Alan.

Later: It's just taken 16 minutes (+/- 0s) to start using the other three cores. Some initialisation!

Oh, and I should have said I'm running BOINC 7.2.0-r1 from the Gentoo package.

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Message 63318 - Posted: 3 Apr 2015, 23:12:49 UTC

Initialisation is taking far too long; it's leaving three-quarters of my resources unused for long periods.

I'm seriously considering dropping this project in favour of several other physics and astrophysics projects that don't leave my system idling.

Energy to power the machine does cost money. I'm happy to spend the money on worthwhile causes and I'd love to keep this project going.

Encourage me...
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ProfileDarrell Tangman

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Message 63505 - Posted: 3 May 2015, 15:49:21 UTC - in response to Message 63318.  

Second the previous message; I just aborted an N-Body task that had accumulated 52 hours of CPU time and was still tying up four CPUs to run a single thread.
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Questions and Answers : Unix/Linux : Milkyway@Home says it's running a task on 4 CPUs, but it isn't.

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