4.3BSD-UWisc/man/cat2/getrusage.2
GETRUSAGE(2) UNIX Programmer's Manual 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
_G_e_t_r_u_s_a_g_e returns information describing the resources util-
ized by the current process, or all its terminated child
processes. The _w_h_o parameter is one of RUSAGE_SELF or
RUSAGE_CHILDREN. The buffer to which _r_u_s_a_g_e 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 */
};
The fields are interpreted as follows:
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_maxrss the maximum resident set size utilized (in
kilobytes).
ru_ixrss an "integral" value indicating the amount of
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GETRUSAGE(2) UNIX Programmer's Manual GETRUSAGE(2)
memory used by the text segment that was also
shared among other processes. This value is
expressed in units of kilobytes * 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 pro-
cess (expressed in units of kilobytes *
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 *
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_majflt the number of page faults serviced that
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_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_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.
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GETRUSAGE(2) UNIX Programmer's Manual GETRUSAGE(2)
NOTES
The numbers _r_u__i_n_b_l_o_c_k and _r_u__o_u_t_b_l_o_c_k 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
The possible errors for _g_e_t_r_u_s_a_g_e are:
[EINVAL] The _w_h_o parameter is not a valid value.
[EFAULT] The address specified by the _r_u_s_a_g_e parameter
is not in a valid part of the process address
space.
SEE ALSO
gettimeofday(2), wait(2)
BUGS
There is no way to obtain information about a child process
that has not yet terminated.
Printed 12/27/86 May 13, 1986 3