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 time a.out 
 106.130u 0.000s 1:46.28 99.8%   0+0k 0+0io 83pf+0w

As per my understanding of the man page:

  • the first value is the time since the code execution started and ended,
  • the second values is the time spent in usermode
  • the third one being in kernel mode

Is the 99.8% indicating time spent in kernel mode?

Also, what does this indicate?

0+0k 0+0io 83pf+0w .

The program definitely takes more than a minute to execute – then why is the first value so small?

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migrated from Sep 21 '11 at 4:30

This question came from our site for professional and enthusiast programmers.

up vote 1 down vote accepted

From the manpage:

The default format is:

    %Uuser %Ssystem %Eelapsed %PCPU (%Xtext+%Ddata %Mmax)k
    %Iinputs+%Ooutputs (%Fmajor+%Rminor)pagefaults %Wswaps

So, 106 seconds spent in userspace, 0 seconds in kernelspace, 1 minute and 46 seconds elapsed "real" time.

As for "why is the first value so small" - it isn't. Note that 106 seconds == 60 seconds + 46 seconds == 1 minute 46 seconds, which is the time elapsed. I don't see a discrepancy there.

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Thank you.. i was getting confused seeing the first u with the first value thinking it was microsecond. Really dumb – f-z-N Sep 21 '11 at 9:10

Use the unix manual page for time:

>man time

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