You say there's no swapping.... but if it's spending system time, and it's the later insertions that are being slow.... AND it gets worse with 3D (which will probably have more DOFs)... it REALLY sounds like you're running out of memory....
How much RAM do you have? How many DOFs? 6 refinement steps is a _lot_ (if it's marking quite a few elements every time). Even with a small mesh that's going to get big quickly. Derek On Fri, Aug 1, 2008 at 11:49 AM, Roy Stogner <[EMAIL PROTECTED]> wrote: > > > -------- Forwarded Message -------- > From: Adam C Powell IV <[EMAIL PROTECTED]> > To: [email protected] > Subject: Ridiculously slow matrix insertion > Date: Mon, 21 Jul 2008 15:34:12 -0400 > > Greetings, > > I'm working on a problem similar to example 14 in 3-D, and the matrix > insertion process in system assembly is taking ridiculous amounts of > time, on the order of 95+% of the solution time. (The perf_log facility > doesn't seem to work; this is based on printf statements at the same > places as those calls.) > > I notice that this takes longer for the later elements than earlier > ones. And the problem is far worse in 3-D than 2-D. With max_r_steps=6 > some of the elements take as long as 0.4 second to insert on a 2.2 GHz > T7500. Also the "time" command shows that about 1/3 of the time is > spent in "system" activity, though there's no swapping going on. > > It's odd, because it seems that this should be very fast in PETSc. That > is, unless it's computing the matrix fill at the same time -- but the > default solver seems to be PETSc's GMRES which doesn't involve fill... > > Where should I start to investigate? > > Thanks, > -Adam > > Adam C. Powell, IV http://www.opennovation.com/ > P.O. Box 249 [EMAIL PROTECTED] > Newton, MA 02464-0002 USA (617) 290-8831 > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's > challenge > Build the coolest Linux based applications with Moblin SDK & win great > prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
