From: mohd ezanee rusli Newsgroups: comp.parallel.mpi Subject: speedup Date: Thu, 25 Mar 1999 16:43:07 +0000 Organization: Electronics and Computer Science, University of Southampton Message-Id: <36FA679A.DBCE9106@ecs.soton.ac.uk> Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="------------D4EC3C7C4B8DD4DA9CD12281" Xref: ukc comp.parallel.mpi:4838 --------------D4EC3C7C4B8DD4DA9CD12281 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit hi everybody. At the moment I'm doing a project to compare the performance of a parallel algorithm and a sequential algorithm. I'm using MPI for the parallel version. My question is about speedup. In theory the speedup is the ratio of the run time of the sequential program to the parallel program running on P processors. And also the execution time for parallel version should be less than sequential. However, from my observation it is not that way. what I see is the execution time for P processor is more than sequential. Therefore the speedup will decrease instead of increase. Any idea why? -- -Mohd Ezanee Rusli- Computer Science part III,University Of Southampton mer296@ecs.soton.ac.uk. 329 Burgess Road, Swaythling, Southampton UK. SO16 3BA tel: 01703 575399 --------------D4EC3C7C4B8DD4DA9CD12281 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit hi everybody.
At the moment I'm doing a project to compare the performance of a parallel algorithm and a sequential algorithm. I'm using MPI for the parallel version. My question is about speedup. In theory the speedup is the ratio of the run time of the sequential program to the parallel program running on P processors. And also the execution time for parallel version should be less than sequential. However, from my observation it is not that way. what I see is the execution time for P processor is more than sequential. Therefore the speedup will decrease instead of increase.
Any idea why? 
-- 
-Mohd Ezanee Rusli-
Computer Science part III,University Of Southampton
mer296@ecs.soton.ac.uk.
329 Burgess Road, Swaythling, Southampton UK. SO16 3BA
tel: 01703 575399
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