[petsc-users] testing scalability for ksp/ex22.c (now ex45.c)

[Francis Poulin]

Hello Barry,

Thanks for offering to look at this.

I configured a different version that does not have the debugger and the results are a lot faster but the efficiency is still similar.  Below you'll see the results.  

n		Tp 		Efficiency
-------------------------------------
1		162		1
2		110		0.74
4		47		0.86
8		24		0.84
16		12		0.84
32		6		0.84

I'm also including the output of the log_summary for n =1 and 2.  

As I said before, this is an SMP machine so I would expect it to be better than the typical cluster.  That being said I am still learning how this works.

I am very happy that I managed to get some encouraging results in a day.  

Cheers, Francis



On 2012-02-24, at 9:08 PM, Jed Brown wrote:

> On Fri, Feb 24, 2012 at 14:43, Francis Poulin <fpoulin at uwaterloo.ca> wrote:
> It seems to scale beautifully starting at 2 but there is a big drop from 1 to 2.  I suspect there's a very good reason for this, I just don't know what.
> 
> Can you send the full output? The smoother is slightly different, so the number of iterations could be different by 1 (for example). The -log_summary part of the output will show us where the time is being spent, so we'll be able to say what did not scale well between 1 and 2 procs.

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