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<DIV dir=ltr align=left><SPAN class=359383522-23052010><FONT color=#0000ff
size=2 face=Arial>It is possible that there is better cache utilization in the
parallel program than in the sequential one. As an experiment, run the
sequential program with only 250 iterations and see if the time is less than
half the time taken by the sequential program with 500
iterations.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=359383522-23052010><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=359383522-23052010><FONT color=#0000ff
size=2 face=Arial>Rajeev</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=359383522-23052010><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV><BR>
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<FONT size=2 face=Tahoma><B>From:</B> mpich-discuss-bounces@mcs.anl.gov
[mailto:mpich-discuss-bounces@mcs.anl.gov] <B>On Behalf Of </B>sankar
s<BR><B>Sent:</B> Sunday, May 23, 2010 6:02 AM<BR><B>To:</B>
mpich-discuss@mcs.anl.gov<BR><B>Subject:</B> [mpich-discuss] comparison of
execution times:<BR></FONT><BR></DIV>
<DIV></DIV>Hi,
<DIV><BR></DIV>
<DIV>I have done a simulation program in C, which contains 500 Replications.
In sequential code these 500 replications will be done one by one and the
combined results will be posted in output at last.</DIV>
<DIV><BR></DIV>
<DIV>Same code I have written for MPI. first 250 replications in processor 0
and next 250 replications in processor 1. after completion of processor 0, it
will send these results to processor 1. Processor 1 combines all the results
and gives the output.</DIV>
<DIV><BR></DIV>
<DIV>I expected, because of doing these parallelism, the execution time
of MPI should be half or some what more than half than sequential code.</DIV>
<DIV><BR></DIV>
<DIV>But parallel code is taking less than half execution time of
sequential code. Some times (1/3rd also). Results point of view it is good.
But I don't understand why it is taking less than half time?</DIV>
<DIV><BR></DIV>
<DIV>am using DELL core2duo processor and windows 7 OS.</DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV>Thank you</DIV></BLOCKQUOTE></BODY></HTML>