getrusage(2)
NAME
getrusage − get information about resource utilization
SYNOPSIS
#include <sys/time.h>
#include <sys/resource.h>
int 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_SELFcalling process
RUSAGE_CHILDRENterminated child processes
If rusage is non-zero, the buffer it points to 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 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.
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 pages). The size of a page is reported by the getpagesize(2) system service and the pagesize(1) utility.
ru_ixrss an “integral” value indicating the amount of memory used which was also shared among other processes. This value is expressed in units of pages ∗ ticks (where a tick is 1/60th of a second) and is calculated by summing the number of shared memory pages in use each time the internal system clock ticks.
ru_idrss an integral value of the amount of unshared memory residing in the data segment of a process (expressed in units of pages ∗ ticks).
ru_isrss an integral value of the amount of unshared memory residing in the stack segment of a process (expressed in units of pages ∗ 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 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.
NOTES
The numbers ru_inblock and ru_oublock account only for real i/o; data supplied by the cacheing mechanism is charged only to the first process to read or write the data.
RETURN VALUE
If the calls succeed, a value of 0 is returned. If an error occurs, the value −1 is returned, and a more precise error code is placed in the global variable errno.
ERRORS
The possible errors are:
[EFAULT] The address specified for rusage is invalid.
[EINVAL] The value specified for who is not one of RUSAGE_SELF or RUSAGE_CHILDREN.
NOTES
If the high resolution timing facility is configured into the currently executing kernel, ru_stime will exclude or include time spent servicing interrupts, depending on what the system timing mode is set to. See hirestmode(2) and CX/UX Programmer’s Guide for more information on the high resolution timing facility.
SEE ALSO
BUGS
There is no way to obtain information about a child process which has not yet terminated.
CX/UX Programmer’s Reference Manual