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January 28, 2008, 13:19 |
Do me a favor and try booting
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#1 |
Guest
Posts: n/a
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Do me a favor and try booting your kernel with the norandmaps kernel parameter and try the same benchmarks. It should reduce TLB misses and possibly increase cache hits for a very very minor trade off in security. If your on a firewalled network increased risk of being hacked is nil.
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January 28, 2008, 13:31 |
I just figured out you don't e
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#2 |
Guest
Posts: n/a
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I just figured out you don't even have to reboot. just write a 0 to the file /proc/sys/kernel/randomize_va_space though a reboot will keep all running processes from having randomized memory allocation.
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January 29, 2008, 03:12 |
Hi Nicolas,
Do you really s
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#3 |
Senior Member
Jens Klostermann
Join Date: Mar 2009
Posts: 117
Rep Power: 17 |
Hi Nicolas,
Do you really show efficiency or is it speedup? In our experience the intel quadcore performs poor with respect to efficiency and speedup up to 8 cores (with worst performance for 8 cores). I think this is because of the architecture so try to go beyond those 8 cores. If we compare OF to commercial solvers, we also see the in the lead (typically 30% to 100% faster ) and I am wondering why? Jens PS One suggestion I have is to reduce your NonOrthogonalCorrectors to 1, I don't think 2 are really necessary. |
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January 29, 2008, 04:31 |
Hello,
Yes Jens, it should
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#4 |
Member
nicolas
Join Date: Mar 2009
Location: Glasgow
Posts: 42
Rep Power: 17 |
Hello,
Yes Jens, it should probably be called speedup; i am plotting cpu_time_1cpu/cpu_time_X_cpu. I'll try to test above 8 cores, not that easy to test here. OF/commercial solvers: *parallel efficiency/speedup: the commercial solver we have here is performing worst -> speed-up is worst. *but convergence AND time/iteration is better for the commercial solver. In the end OF takes around twice as much time to get to a converged solution. But there are quite a few parameters i can still look at. Next one is checking NonOrthogonalCorrectors=1 (thanks for the idea). Thanks Conn, i ll also give try to your suggestion, sounds interesting. Nico |
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January 29, 2008, 13:01 |
You don't NEED any nonOrthogon
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#5 |
Senior Member
Eugene de Villiers
Join Date: Mar 2009
Posts: 725
Rep Power: 21 |
You don't NEED any nonOrthogonal correctors for a steady state run (unless your mesh is particularly poor). Non-orthogonal correction is done even if there are no additional corrector steps and the solution should be identical at convergence.
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