[petsc-dev] SuiteSparse 4.0

[Jed Brown]

You can't use cublas everywhere because it's better to do small sizes on
the CPU and different threads need to be able to operate independently
(without multiple devices).

Yes, try a PETSc example before your own code. Did petsc build without any
changes to the cholmod interface? ALWAYS send the error message/stack
trace---even if we don't have an answer, it usually tells us how difficult
the problem is likely to be to fix.
On Jun 13, 2012 8:09 AM, "Dave Nystrom" <dnystrom1 at comcast.net> wrote:

> Well, I tried it last night but without success.  I got a memory corruption
> error when I tried running my app.  I suppose I should try first to get it
> working with a petsc example.  I'm building SuiteSparse but only using
> cholmod out of that package.  Several of the SuiteSparse packages use blas
> but cholmod is the only one so far that has the option to use cublas.  Tim
> gets about a 10x speedup over the single core result when using cublas on
> an
> example problem that spends a lot of time in blas.  So seems worth trying.
> Anyway, I think I must be doing something wrong so far.  But for the same
> problem, Tim gets about a 20+ percent speedup over using multi-threaded
> Goto
> blas.
>
> Probably a better solution for petsc would be support for using cublas for
> all of the petsc blas needs.  Why should just one petsc blas client have
> access to cublas?  But not sure how much work is involved for that - I see
> it
> is on the petsc ToDo list.  I will try again tonight but would welcome
> advice
> or experiences from anyone else who has tried the new cholmod.
>
> Dave
>
> Jed Brown writes:
>  > Nope, why don't you try it and send us a patch if you get it working.
>  >
>  > On Wed, Jun 13, 2012 at 12:49 AM, Dave Nystrom <dnystrom1 at comcast.net
> >wrote:
>  >
>  > > Has anyone tried building petsc-dev to use cholmod-2.0 which is part
> of
>  > > SuiteSparse-4.0 with the cholmod support for using cublas enabled?  I
> am
>  > > interested in trying the cublas support for cholmod to see how it
> compares
>  > > with mkl and goto for my solves.
>  > >
>  > > Thanks,
>  > >
>  > > Dave
>  > >
>
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