NAME

getrusage − get information about resource utilization

SYNOPSIS

#include <sys/time.h>
#include <sys/resource.h>

getrusage(who, rusage)
int who;
struct rusage ∗rusage;

DESCRIPTION

getrusage() returns information about the resources utilized by the current process, or all its terminated child processes.  The who parameter is one of RUSAGE_SELF or RUSAGE_CHILDREN. The buffer to which rusage points will be filled in with the following structure:

structrusage {
struct timeval ru_utime;/∗ user time used ∗/
struct timeval ru_stime;/∗ system time used ∗/
intru_maxrss;
intru_ixrss;/∗ integral shared text memory size ∗/
intru_idrss;/∗ integral unshared data size ∗/
intru_isrss;/∗ integral unshared stack size ∗/
intru_minflt;/∗ page reclaims ∗/
intru_majflt;/∗ page faults ∗/
intru_nswap;/∗ swaps ∗/
intru_inblock;/∗ block input operations ∗/
intru_oublock;/∗ block output operations ∗/
intru_msgsnd;/∗ messages sent ∗/
intru_msgrcv;/∗ messages received ∗/
intru_nsignals;/∗ signals received ∗/
intru_nvcsw;/∗ voluntary context switches ∗/
intru_nivcsw;/∗ involuntary context switches ∗/
};

The fields are interpreted as follows:

ru_utime
the total amount of time spent executing in user mode. Time is given in seconds:microseconds.

ru_stime
the total amount of time spent in the system executing on behalf of the process(es). Time is given in seconds:microseconds.

ru_maxrss
the maximum resident set size utilized.  Size is given in pages (the size of a page, in bytes, is given by the getpagesize(2) system call). 

ru_ixrss
an “integral” value indicating the amount of memory used by the text segment which was also shared among other processes.  This value is expressed in units of pages ∗ clock ticks (1 tick = 1/50 second).  The value is calculated by summing the number of shared memory pages in use each time the internal system clock ticks, and then averaging over 1 second intervals.

ru_idrss
an integral value of the amount of unshared memory residing in the data segment of a process. The value is given in pages ∗ clock ticks.

ru_isrss
an integral value of the amount of unshared memory residing in the stack segment of a process.  The value is given in pages ∗ clock ticks.

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.

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

ru_nswap
the number of times a process was “swapped” out of main memory.

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

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

ru_msgsnd
the number of messages sent over sockets.

ru_msgrcv
the number of messages received from sockets.

ru_nsignals
the number of signals delivered.

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).

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 ru_inblock and 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. 

ERRORS

getrusage() will fail if:

EINVAL The who parameter is not a valid value. 

EFAULT The address specified by the rusage argument is not in a valid portion of the process’s address space. 

SEE ALSO

gettimeofday(2), wait(2)

BUGS

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

Sun Release 4.0  —  Last change: 25 September 1987