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getrusage.2freebsd

BSD mandoc

NAME

getrusage - get information about resource utilization

LIBRARY

Lb libc

SYNOPSIS

In sys/types.h In sys/time.h In sys/resource.h Fd #define      RUSAGE_SELF      0 Fd #define   RUSAGE_CHILDREN-1 Ft int Fn getrusage int who struct rusage *rusage

DESCRIPTION

The
Fn getrusage system call returns information describing the resources utilized by the current process, or all its terminated child processes. The Fa who argument is either RUSAGE_SELF or RUSAGE_CHILDREN The buffer to which Fa rusage points will be filled in with the following structure:

 struct rusage {
         struct timeval ru_utime; /* user time used */
         struct timeval ru_stime; /* system time used */
         long ru_maxrss;          /* max resident set size */
         long ru_ixrss;           /* integral shared text memory size */
         long ru_idrss;           /* integral unshared data size */
         long ru_isrss;           /* integral unshared stack size */
         long ru_minflt;          /* page reclaims */
         long ru_majflt;          /* page faults */
         long ru_nswap;           /* swaps */
         long ru_inblock;         /* block input operations */
         long ru_oublock;         /* block output operations */
         long ru_msgsnd;          /* messages sent */
         long ru_msgrcv;          /* messages received */
         long ru_nsignals;        /* signals received */
         long ru_nvcsw;           /* voluntary context switches */
         long ru_nivcsw;          /* involuntary context switches */
 };
 

The fields are interpreted as follows:

Fa ru_utime

the total amount of time spent executing in user mode.

Fa ru_stime

the total amount of time spent in the system executing on behalf of the process(es).

Fa ru_maxrss

the maximum resident set size utilized (in kilobytes).

Fa ru_ixrss

an ``integral'' value indicating the amount of memory used by the text segment that was also shared among other processes. This value is expressed in units of kilobytes * ticks-of-execution. Ticks are statistics clock ticks. The statistics clock has a frequency of Fn sysconf _SC_CLK_TCK ticks per second.

Fa ru_idrss

an integral value of the amount of unshared memory residing in the data segment of a process (expressed in units of kilobytes * ticks-of-execution).

Fa ru_isrss

an integral value of the amount of unshared memory residing in the stack segment of a process (expressed in units of kilobytes * ticks-of-execution).

Fa ru_minflt

the number of page faults serviced without any I/O activity; here I/O activity is avoided by ``reclaiming'' a page frame from the list of pages awaiting reallocation.

Fa ru_majflt

the number of page faults serviced that required I/O activity.

Fa ru_nswap

the number of times a process was ``swapped'' out of main memory.

Fa ru_inblock

the number of times the file system had to perform input.

Fa ru_oublock

the number of times the file system had to perform output.

Fa ru_msgsnd

the number of IPC messages sent.

Fa ru_msgrcv

the number of IPC messages received.

Fa ru_nsignals

the number of signals delivered.

Fa ru_nvcsw

the number of times a context switch resulted due to a process voluntarily giving up the processor before its time slice was completed (usually to await availability of a resource).

Fa ru_nivcsw

the number of times a context switch resulted due to a higher priority process becoming runnable or because the current process exceeded its time slice.

NOTES

The numbers Fa ru_inblock and Fa ru_oublock account only for real I/O; data supplied by the caching mechanism is charged only to the first process to read or write the data.

RETURN VALUES

Rv -std getrusage

ERRORS

The Fn getrusage system call will fail if:

Bq Er EINVAL

The Fa who argument is not a valid value.

Bq Er EFAULT

The address specified by the Fa rusage argument is not in a valid part of the process address space.

SEE ALSO

gettimeofday(2), wait(2), clocks(7)

HISTORY

The Fn getrusage system call appeared in BSD 4.2

BUGS

There is no way to obtain information about a child process that has not yet terminated.