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I asked the original question, and I have a follow up. Like it or not, multi-core CPUs have been thrust upon us by the manufacturers and many of us are more likely to have access to a shared memory, multi core/multi processor machine, than a properly built cluster with MPI in mind.<div><br class="webkit-block-placeholder"></div><div>So, two questions in this direction:</div><div><br class="webkit-block-placeholder"></div><div>1. How feasible would it be to implement OpenMP in PETSc so that multi core CPUs could be properly used?</div><div><br class="webkit-block-placeholder"></div><div>2. Even if we are building a cluster, it looks like AMD/Intel are thrusting multi core up on is. To that end, what is the feasibility of merging MPI and OpenMP so that between nodes, we use MPI, but within each node, OpenMP is used to take advantage of the multiple cores.</div><div><br><div> <p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">-gideon</font></p> </div><br><div><div>On Nov 18, 2007, at 3:53 PM, Aron Ahmadia wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Hi Ben,</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">You're asking a question that is very specific to the program you're</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">running.<span class="Apple-converted-space"> </span>I think the general consensus on this list has been that for</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">the more common uses of PETSc, getting dual-cores will not speed up</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">your performance as much as dual-processors.<span class="Apple-converted-space"> </span>For OS X, dual-cores are</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">pretty much the baseline now, so I wouldn't worry too much about it.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">~A</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">On Nov 18, 2007 3:34 PM, Ben Tay <<a href="mailto:zonexo@gmail.com">zonexo@gmail.com</a>> wrote:</div> <blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Hi,</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">someone was talking abt core 2 duo performance on os x in some previous</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">email. it seems that due to memory issues, it's not possible to get 2x the</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">performance. there's also some mention of amd vs intel dual core.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">for computation using PETSc, is there any reason to buy one instead of the</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">other? Also, supposed I use winxp + mpich2 + PETSc on a dual core, what sort</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">of performance increase can we expect as compared to PETSc + nompi on the</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">same machine?</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">or is that too difficult an answer to give since there are too many factors?</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">thank you</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">regards</div> </blockquote><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> </blockquote></div><br></div></body></html>