GETRUSAGE(2) BSD GETRUSAGE(2)
NAME
getrusage - get information about resource utilization
SYNOPSIS
#include <sys/time.h>
#include <sys/resource.h>
#define RUSAGE_SELF 0 /* calling process */
#define RUSAGE_CHILDREN -1 /* terminated child processes */
getrusage(who, rusage)
int who;
struct rusage *rusage;
DESCRIPTION
getrusage returns information describing 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:
struct rusage {
struct timeval ru_utime; /* user time used */
struct timeval ru_stime; /* system time used */
int ru_maxrss;
int ru_ixrss; /* integral shared text memory size */
int ru_idrss; /* integral unshared data size */
int ru_isrss; /* integral unshared stack size */
int ru_minflt; /* page reclaims */
int ru_majflt; /* page faults */
int ru_nswap; /* swaps */
int ru_inblock; /* block input operations */
int ru_oublock; /* block output operations */
int ru_msgsnd; /* messages sent */
int ru_msgrcv; /* messages received */
int ru_nsignals; /* signals received */
int ru_nvcsw; /* voluntary context switches */
int ru_nivcsw; /* involuntary context switches */
};
Domain/OS BSD uses only the following fields:
ru_utime The total amount of time spent executing in user mode.
ru_stime The total amount of time spent in the system executing on
behalf of the process(es).
ru_majflt The number of page faults serviced that required I/O
activity.
ru_nsignals The number of signals delivered.
ERRORS
The possible errors for getrusage are:
[EINVAL] The who parameter is not a valid value.
[EFAULT] The address specified by the rusage parameter is not in a
valid part of the process address space.
SEE ALSO
gettimeofday(2), wait(2)
NOTES
Other implementations may interpret the rusage fields as follows:
ru_maxrss The maximum resident set size utilized (in kilobytes).
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
multiplied by seconds-of-execution and 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 (expressed in units of
kilobytes multiplied by seconds-of-execution).
ru_isrss An integral value of the amount of unshared memory residing
in the stack segment of a process (expressed in units of
kilobytes multiplied by seconds-of-execution).
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_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_outblock The number of times the file system had to perform output.
ru_msgsnd The number of IPC messages sent.
ru_msgrcv The number of IPC messages received.
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.
Under other implementations, the numbers ru_inblock and ru_outblock
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.
BUGS
There is no way to obtain information about a child process that has not
yet terminated.