From: Tim Kroeger <tim.kroeger@ce...>  20080827 10:21:43

Dear Roy, On Tue, 26 Aug 2008, Roy Stogner wrote: >> (In the current state, my code does not show any speedup on 20 processors >> compared with 1 processor, because it spends apparently 95% of the time in >> EquationSystems::reinit().) > > Could you insert some more finegrained performance logs and verify > that it's really project_vector causing most of the delay? That's an > astonishingly lousy result. Well, the '95%' were just the sensed percentage. To find out how much it really is, I now used the PerfLog class. I have to admit that I had not used that class ever before, so I am not completely sure whether I understood the concept correctly. I did the following: In EquationSystems::reinit(), I added some PerfLog stuff (see attached modified copy of equation_systmes.C). Also, in my main program, I added a PerfLog instance that measures the complete computation time. Attached are the results for 1 cpu and for 20 cpus. Note that EquationSystems::reinit() has been called 6 times, hence there are 6 sections about this. (This is where I'm not sure whether I understood the concept correctly.) Note that the total time the computation spends in this function is about 220 seconds for 1 cpu and about 230 seconds for 20 cpus, whereas the overall total computation time is about 660 seconds for 1 cpu and about 345 seconds for 20 cpus. Hence, the speedup is less than a factor of 2. Also, for 20 cpus, 67% of the time is spent in EquationSystmes::reinit(). I hope this information is sufficient for you. If not, please let me know what else you need. By the way: After the last refinement, the mesh consists of 98897 elements and 22675 nodes for 1 cpu, 98841 elements and 22662 nodes for 20 cpus. Best Regards, Tim  Dr. Tim Kroeger Phone +494212187710 tim.kroeger@..., tim.kroeger@... Fax +494212184236 MeVis Research GmbH, Universitaetsallee 29, 28359 Bremen, Germany Amtsgericht Bremen HRB 16222 Geschaeftsfuehrer: Prof. Dr. H.O. Peitgen 