These functions are used to retrieve resource usage information:

This function returns an object that describes the resources

The fields of the return value each describe how a particular system

resource has been used, e.g. amount of time spent running is user mode

or number of times the process was swapped out of main memory. Some

values are dependent on the clock tick internal, e.g. the amount of

memory the process is using.

For backward compatibility, the return value is also accessible as

a tuple of 16 elements.

The fields \member{ru_utime} and \member{ru_stime} of the return value

are floating point values representing the amount of time spent

executing in user mode and the amount of time spent executing in system

mode, respectively. The remaining values are integers. Consult the

\manpage{getrusage}{2} man page for detailed information about these

values. A brief summary is presented here:

\begin{tableiii}{r|l|l}{code}{Index}{Field}{Resource}

\lineiii{0}{\member{ru_utime}}{time in user mode (float)}

\lineiii{1}{\member{ru_stime}}{time in system mode (float)}

\lineiii{2}{\member{ru_maxrss}}{maximum resident set size}

\lineiii{3}{\member{ru_ixrss}}{shared memory size}

\lineiii{4}{\member{ru_idrss}}{unshared memory size}

\lineiii{5}{\member{ru_isrss}}{unshared stack size}

\lineiii{6}{\member{ru_minflt}}{page faults not requiring I/O}

\lineiii{7}{\member{ru_majflt}}{page faults requiring I/O}

\lineiii{8}{\member{ru_nswap}}{number of swap outs}

\lineiii{9}{\member{ru_inblock}}{block input operations}

\lineiii{10}{\member{ru_oublock}}{block output operations}

\lineiii{11}{\member{ru_msgsnd}}{messages sent}

\lineiii{12}{\member{ru_msgrcv}}{messages received}

\lineiii{13}{\member{ru_nsignals}}{signals received}

\lineiii{14}{\member{ru_nvcsw}}{voluntary context switches}

\lineiii{15}{\member{ru_nivcsw}}{involuntary context switches}

\end{tableiii}

\versionchanged[Added access to values as attributes of the

returned object]{2.3}