Yes, you could be correct. When developing parallelized programs like this one, I use two tools to help me identify how well or poorly my code is working. They are htop and iostat. htop is variation of the venerable top command that orignated on VMS and found its way to Linux and the Mac. It lets me monitor processor core utilization and near real time performance statistics of my process(es). iostat monitors the read and write rates to my hard disks. I run it as iostat 1 and it provides IO statistics on a second by second basis.

Given my personal experience, these output from these tools indicated that I was no IO bound when running at the longer times - the disk transfer rate was too low for IO to have been a factor. Now, with the reduced times, I am seeing much higher IO rates and IO is definitely the limiting process

Thanks!, lbe

In reply to Re^2: MCE: Slow IPC between child and gather process in parent by learnedbyerror
in thread MCE: Slow IPC between child and gather process in parent by learnedbyerror

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