CPU time is hugely different form real time.
CPU time is how much time something spent on the CPUs, while real time is what you and I experience as humans.
Think about this: assume you have the same job running over the same data but on one 20 node cluster, then a 200 node cluster. Overall, the same amount of CPU time will be used on both clusters, but the 200 node cluster will run 10x faster in real time.
CPU time is a useful metric when you have a shared system with lots of jobs running on it at the same time.
CPU time is how much time something spent on the CPUs, while real time is what you and I experience as humans.
Think about this: assume you have the same job running over the same data but on one 20 node cluster, then a 200 node cluster. Overall, the same amount of CPU time will be used on both clusters, but the 200 node cluster will run 10x faster in real time.
CPU time is a useful metric when you have a shared system with lots of jobs running on it at the same time.
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