On Fri, 18 Apr 2008, Ben Tay wrote: > Hi, > > I've email my school super computing staff and they told me that the queue > which I'm using is one meant for testing, hence, it's > handling of work load is not good. I've sent my job to another queue and it's > run on 4 processors. It's my own code because there seems > to be something wrong with the server displaying the summary when using > -log_summary with ex2f.F. I'm trying it again.
Thats wierd. We should first make sure ex2f [or ex2] are running properly before looking at your code. > > Anyway comparing just kspsolve between the two, the speedup is about 2.7. > However, I noticed that for the 4 processors one, its > MatAssemblyBegin is? 1.5158e+02, which is more than KSPSolve's 4.7041e+00. So > is MatAssemblyBegin's time included in KSPSolve? If not, > does it mean that there's something wrong about my MatAssemblyBegin? MatAssemblyBegin is not included in KSPSolve(). Something wierd is going here. There are 2 possibilities. - whatever code you have before matrix assembly is unbalanced, so MatAssemblyBegin() acts as a barrier . - MPI communication is not optimal within the node. Its best to first make sure ex2 or ex2f runs fine. As recommended earlier - you should try latest mpich2 with --with-device=ch3:nemesis:newtcp and compare ex2/ex2f performance with your current MPI. Satish