[graph-tool-tickets] [graph-tool] Ticket #156: OpenMP problem in katz and pagerank

graph-tool webmaster at skewed.de
Mon Jun 9 13:07:54 UTC 2014


#156: OpenMP problem in katz and pagerank
reopened enhancement
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Reporter: anonymous
Owner: tiago peixoto
Priority: normal
Milestone: 2.2

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Comment (by td):

Hi peixoto,

This is interesting. I tried your suggestion. It indeed worked well in terms of balancing the threads. I can see all of them at 100% now, on the 4CPU machine.

Although... the computation is MUCH slower!

Details:

- ''Unmodified'': 57 iterations, **12s** compute time (for some reason it's faster than before (18s) - I guess the machine had some side workload before (or might have been swapping))
- ''Modified'': 57 iterations, **~19s** compute time

I tested several times. And I also tested giving its process a "niceness" value of -19 to be sure it's the main CPU process. 
None of those run swapped, plenty of memory was still available.

I am not quite sure what's going on here.
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Ticket URL: <URL:http://graph-tool.skewed.de/ticket/156>
graph-tool <URL:http://graph-tool.skewed.de>
An efficient python module for graph analysis and manipulation.


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