NAME

getrusage − get information about resource utilization

SYNOPSIS

#include <resource.h>

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

DESCRIPTION

Getrusage returns information describing the resources utilitized by the current process, or all its terminated child processes.  If the who parameter is RUSAGE_SELF (0), the usage values are for only the calling process.  If who is RUSAGE_CHILDREN (−1), the values returned are for all child processes which have terminated.  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 " ∗/
intru_isrss;/∗ integral unshared stack " ∗/
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 kilobytes). 

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 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 process (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 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_outblock the number of times the file system had to perform output. 

ru_msgsnd the number of ipc message sent. 

ru_msgrcv the number of ipc message 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 availabilty 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_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. 

SEE ALSO

gettimeofday(2), wait(2)

BUGS

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

Sun System Release 0.3  —  25 April 1983