dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Sun, Oct 14, 2012 at 02:44:09PM +0100, Garth N. Wells wrote:
> You cannot
>
>   (a) rely on machines that manage dynamically the CPU clock speed and
> spin down the hard disk, especially laptops, to generate reliable
> (short) timings.

It's usually quite ok for doing that. I use cpufreq-set to set the
highest clock rate and cpufreq-selector to set the CPU 'governor' to
'performance'.

>   (b) get a tuned installation with Dorsal
>
> My times (not using Dorsal) are:
>
>     Init MPI                     |      0.018783    0.018783     1
>     Init PETSc                 |    0.00043392  0.00043392     1
>     Init dof vector             |    0.00064111  0.00064111     1

Somewhat better now after rebuilding with newly built petsc-3.3-p3:

  Init PETSc                  |      0.026619    0.026619     1

But still 2 orders of magnitude worse than for you and Johannes.

I don't see why it needs to be worse than Dorsal. The only difference
is that the Dorsal script is typing out the build commands instead of
doing it manually. So it should just be a matter of which options
Dorsal is using.

Dorsal is using these options:

COPTFLAGS=-O2
          --with-debugging=0 --with-shared-libraries=1
          --with-clanguage=cxx --with-c-support=1"

for external_pkg in umfpack hypre mumps scalapack blacs ptscotch
scotch metis parmetis; do
    CONFOPTS="${CONFOPTS} --download-${external_pkg}=1"
done

Any of these that should be avoided? Any that should be added for a
better PETSc build?

--
Anders