[petsc-users] Question about LogSummary

[Matthew Knepley]

On Mon, Mar 25, 2013 at 12:42 AM, Blaise A Bourdin <bourdin at lsu.edu> wrote:

>
>  On Mar 23, 2013, at 11:50 PM, Matthew Knepley <knepley at gmail.com>
>  wrote:
>
>  On Sun, Mar 24, 2013 at 12:24 PM, Blaise A Bourdin <bourdin at lsu.edu>wrote:
>
> Hi,
>
> I am trying to do some scaling tests but can't figure out something about
> LogSummary: When no custom stages / events are defined, how come "Main
> Stage" is not 100% of the time? What is not counted? Here is a example of
> what I get:
>
>
>  Library loading?
>
> Really? Is there anything I can do to test if it really is library loading
> or to reduce loading time? I am attaching the full log summary
>   Blaise
>
>
>     Matt
>
>
> Summary of Stages:   ----- Time ------  ----- Flops -----  --- Messages
> ---  -- Message Lengths --  -- Reductions --
>                         Avg     %Total     Avg     %Total   counts
> %Total     Avg         %Total   counts   %Total
>  0:      Main Stage: 2.5763e+03  65.1%  3.2380e+15 100.0%  1.230e+11
> 100.0%  8.493e+02      100.0%  7.013e+06  97.0%
>
> Where is the missing 35% of the time? I call PetscLogBegin right after
> PetscInitialize.
>
>
Okay, the total time is the time between PetscLogBegin() and the first
several lines of PetscLogView(), before all the reductions.
Thus it does not look like library loading is responsible.

In this log, the main routine seems to be KSPSolve which takes 1.5e3. It
looks like some time in this app is just not
being logged. That would take popping the current stage and then pushing it
again afterwards I think. We would have
to know more about the code.

    Matt


>
> Blaise
>
>
> --
> Department of Mathematics and Center for Computation & Technology
> Louisiana State University, Baton Rouge, LA 70803, USA
> Tel. +1 (225) 578 1612, Fax  +1 (225) 578 4276
> http://www.math.lsu.edu/~bourdin
>
>
>
>
>
>
>
>
>
>
>
>  --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
>
>    --
>  Department of Mathematics and Center for Computation & Technology
>  Louisiana State University, Baton Rouge, LA 70803, USA
>  Tel. +1 (225) 578 1612, Fax  +1 (225) 578 4276
> http://www.math.lsu.edu/~bourdin
>
>
>
>
>
>
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20130325/c12a87f2/attachment.html>