Why my cp2k.popt is running much slower than cp2k.sopt?

hawk2012 hawk2... at gmail.com
Sat Jul 19 21:34:56 CEST 2008


Dear All:

With the help from this discussion group I successfully compiled both
serial and parallel executables of cp2k with g95 compiler and
mpich1.2.6.

However, with the same input file I found that it took much longer
time to run cp2k.popt with 4 CPUs than that to run cp2k.sopt with 1
CPU.
Attached file log.sopt is the output file for cp2k.sopt with 1 CPU
while log.popt-4CPUs is the output file for cp2k.popt with 4 CPUs.
It looks like the job was really running in parallel with 4 CPUs from
the output file log.popt-4CPUs because 4 processe numbers were shown
and Total number of message passing processes is also 4 which was
decomposed as 2x2 with Number of processor rows 2 and Number of
processor cols 2. When I typed command 'top', I really saw four
cp2k.popt processes were actually running.

It is so weird. Is this due to the special input file I used or
something else?
Could anyone take a look at these two output files and tell me what is
the possible reason?


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