Hello,<br> I am neither a regular Petsc user nor contributor so preemptive apologies if I am completely off the line here.<br><br>I am not sure if the original poster had hyper-threading in mind when he asked about multi-threading, in case that was the idea, I don't think using petsc with MKL (HT) is going to give any benefit, I don't think MKL is really resource insensitive. <br>
<br>Also I wonder what percentage of the code is actually blas/lapack intensive to make any significant dent in wall cock?<br><br>of course +1 to everything else posed above.<br><br>Cheers,<br><br>C.S.N<br><br><div class="gmail_quote">
On Mon, Mar 14, 2011 at 8:23 PM, Barry Smith <span dir="ltr"><<a href="mailto:bsmith@mcs.anl.gov">bsmith@mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im"><br>
On Mar 14, 2011, at 7:48 PM, Lisandro Dalcin wrote:<br>
<br>
> On 14 March 2011 20:48, Barry Smith <<a href="mailto:bsmith@mcs.anl.gov">bsmith@mcs.anl.gov</a>> wrote:<br>
>><br>
>> Eric,<br>
>><br>
>> With the current PETSc design that uses one MPI process per core I am not sure that it makes sense to use multi-threaded MKL since the processes are already using all the cores. I could be wrong.<br>
>><br>
>> Barry<br>
>><br>
><br>
> Well, I think that PETSc should support sequential codes using<br>
> multi-threaded blas-lapack<br>
<br>
</div> That is support and someone can do it just by using parallel blas.<br>
<br>
> and perhaps some OpenMP.<br>
<br>
Again users can use openmp in their sequential PETSc code, we don't stop them.<br>
<br>
<br>
Barry<br>
<div class="im"><br>
<br>
> Moreover, perhaps<br>
> we could get some little speedup in MatMult for these kinds of<br>
> users/applications.<br>
<br>
</div> If you aren't willing to pay the entry fee to parallel computing with MPI then you shouldn't be allowed any benifits of parallel PETSc :-). Actually we will eventually support the "hybrid" model.<br>
<div><div></div><div class="h5"><br>
><br>
> --<br>
> Lisandro Dalcin<br>
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</div></div></blockquote></div><br>