Given the code the OP has supplied

That's the pertinent point. The OP has not supplied the full code so we can only guess as to what the rest of it is doing. Further, the fact that the durations reported are wallclock times means that any other process could also be interfering with the resultant durations reported.

That's not to say that your suggestion that the processes are IO-bound is wrong or even unlikely and I too suspect that this will turn out to be the limiting factor in the OP's case. But it is just an guess at this point even if an educated one.

In reply to Re^3: Problem in creating process by hippo
in thread Problem in creating process by ravi45722

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