Dear blogosphere

Has anyone else seen really bogus results when using “time” on multi-core systems?

For example:

real 0m4.986s user 0m35.106s sys 0m0.224s

This system only has a single HT cpu: 700% utilisation is just completely bogus.

Can anyone explain this?

2 thoughts on “Dear blogosphere”

  1. It perfectly makes sense. real is the “wall clock time” (gettimeofday() at the end minus the same at the beginning). user and sys are “cpu time”, so if you have 2 cpus working full time during 1s, then you have 2s of user+sys. To get 700%, you’d need at least 7 cpus/cores (mostly likely 8?). Is that like a dual cpu with dual core with hyperthreading? Or you just have 8 physical cores?

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