cannot run collatz except at nice=19 in karmic
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Message boards : Unix/Linux : cannot run collatz except at nice=19 in karmic

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Profile BeemerBiker
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Message 7300 - Posted: 17 Apr 2010, 18:18:36 UTC

I have two almost identical systems, Opteron 270's, GTS250, 6.10.44. The only difference seems to be that collatz runs at nice=10 in Dotsch_UX (ubuntu 8.1) and at nice=19 in Karmic (9.1 ubuntu)

That makes a big difference as I have just discovered. BTW, I tried re-niceing to 10 but the next collatz task picks back up at 19. I do now know how to keep it at 10.

Dotsch_UX


Karmic





This runs Dotsch_UX (ubuntu 8.1) and nice is set to 10 for collatz. Other tasks are at 19. Note that all of the runtime average about 2100 seconds (same as gpu time) and the cpu time is about 30 seconds.

This identical system runs Ubuntu 9.1 and nice is stuck at 19. If I renice collatz the next task goes back to 19. If you look at the statistics you will see two somewhat good results, the rest are way up at 20,000. The reason that I got two fairly good results is because I set %cpu to 75 to free up one of the 4 cores for collatz. I would not have to do that if I could set nice to 10.

thanks for looking

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Message 7310 - Posted: 18 Apr 2010, 6:09:01 UTC

SOLVED - I finally got collatz to run at nice=0 in Karmic which solved my GPU feeding problem. I also learned something (possibly)

I installed the recent (2.3 actually) linux cuda toolkit from nvidia. After doing ldconfig, the tool ldd ...collatz... showed that I was now using the 2.3 version and that seems to have got me nice=0. So - I am assuming the problem was using an older library, 2.2, that came with the collatz linux package. That one was showing nice=19.


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