[Trilinos-Users] Performance of InsertGlobalValue() in Epetra

Williams, Alan B william at sandia.gov
Thu Apr 17 15:48:36 MDT 2008


Andrea,

That is a large and unexpected performance difference.

I looked through the FECrsMatrix code and there is no function called exactly 'InsertGlobalValue'. Do you mean one of the overloaded 'InsertGlobalValues' functions? There are several of these, both in FECrsMatrix and its base class CrsMatrix. Can you tell which of these it is?

I'll set up a test of my own and attempt to reproduce this.
Alan


> -----Original Message-----
> From: trilinos-users-bounces at software.sandia.gov
> [mailto:trilinos-users-bounces at software.sandia.gov] On Behalf
> Of andrea3.villa at mail.polimi.it
> Sent: Thursday, April 17, 2008 8:17 AM
> To: trilinos-users at software.sandia.gov
> Subject: [Trilinos-Users] Performance of InsertGlobalValue() in Epetra
>
>   Hi,
>
> I've a problem assembling a FECrsMatrix, in particoular in the
> InsertGlobalValue() function. While on my laptop an assemble process
> of a 500.000 row square matrix takes about 50 seconds, on my
> workstation
> it takes about 2300 seconds. I've made a profile of the code
> I've found
> that the difference is inside the InsertGlobalValue() function.
>
> The laptop is:
> 2.5Ghz Intel T9300 (4Mb cache), 4Gb ram, with OS: Suse 10.3
>
> The worstation is:
> 2.0Ghz AMD Opteron 8212 (1Mb cache), 16Gb ram, with OS: Scientific
> Linux 5.0
>
> On both I've installed Trilinos 8.0.5, with this flags:
> CXXFLAGS="-DMPICH_SKIP_MPICXX -O3"
> CFLAGS="-O3"
> FFLAGS="-O5 -funroll-all-loops -ftree-vectorize"
>
> Have anyone experienced a similar problem?
> Any idea to close the gap?
>
> Thanks for any help,
>
>     Andrea V.
>
>
>
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> Trilinos-Users at software.sandia.gov
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