Reporting cpu times to profile KSPSolve (and others)

Matthew Knepley knepley at
Thu May 8 22:19:45 CDT 2008

On Thu, May 8, 2008 at 10:09 PM, Dave May <dave.mayhem23 at> wrote:
> Hey petsc folk,
>     What is the best way to obtain timing information to profile the
> performance
> of KSPSolve (or SNESSolve)? Currently I have written some specific KSP
> monitors,
> but it I think it would be useful to have access to this information all the
> time without
>  having to go through the monitor. It seems like each object should know how
> to time
> some of its operations.
> It would be very useful to have functions such as
>   KSPGetCPUTime(KSP ksp,PetscLogDouble *time)
>  to report the total solution time required by the KSPSolve() and
>   KSPGetCPUTimeHistory(KSP ksp,PetscLogDouble *time[],PetscInt *na)
> which is like KSPGetResidualHistory() but returns the accumulated cpu time
> for each
>  iterate
> It would also be useful to have a default KSP monitor which could report the
> time per iterate
> or accumulate time. For example something like
>   40 KSP Residual norm 1.519638506430e-01 Time 1.000000000000e-03
>    41 KSP Residual norm 1.510346481853e-01 Time 1.510346481853e-02
> Is there a better approach to what I've been doing and are there plans to
> add any
> additional features to help profile individual operations on each object?

Maybe you could motivate it by giving a use case? So far, I have never needed
anything but the KSPSolve() event and stages to separately aggregate different
types of solves.


> Cheers,
>     Dave
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

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