-------- Forwarded Message --------
From: Adam C Powell IV <[EMAIL PROTECTED]>
To: [email protected]
Subject: Re: [Libmesh-users] How long does the system assembling need?
Date: Thu, 31 Jul 2008 14:08:56 -0400
On Thu, 2008-07-31 at 07:57 -0500, Roy Stogner wrote:
> On Thu, 31 Jul 2008, Shengli Xu wrote:
>
> > Roy, Could you tell me what specific profiling information should be
> > gotten? I have to solve this problem.
>
> Just this: "Exactly where is the delay occurring?" If you're using
> our PerfLog objects, for example, you could create one in the
> assembly, activate it right before the matrix adds, and deactivate it
> right after; if that ends up being responsible for most of your
> runtime then you've verified that my "bad matrix assembly" hypothesis
> was correct. If not, then something else in your assembly is taking
> way too long (calling FE::reinit inside the quadrature loop?); you can
> use fine-grained PerfLog objects to test that out too.
I can corroborate the problem. For example, using example 14 in 3-D
with a good number of max_r_steps (say 6 or more), matrix insertion
dominates the run time.
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. With max_r_steps=7, PerfLog shows this is showing 97.98% of the
time is spent in "assemble()", with less than 11000 degrees of freedom!
Also the "time" command shows that about 1/3 of the time is spent in
"system" activity, though there's plenty of memory available and no
swapping going on.
There's something very inefficient about the insertion process...
-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
