getrusage
- get information about resource utilization
LIBRARY
Lb libc
SYNOPSIS
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
Fd #defineRUSAGE_SELF 0
Fd #defineRUSAGE_CHILDREN-1
int
getrusage (int who struct rusage *rusage);
DESCRIPTION
The
getrusage ();
system call
returns information describing the resources utilized by the current
process, or all its terminated child processes.
The
Fa who
argument is either
RUSAGE_SELF
or
RUSAGE_CHILDREN
The buffer to which
Fa 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 */
long ru_maxrss; /* max resident set size */
long ru_ixrss; /* integral shared text memory size */
long ru_idrss; /* integral unshared data size */
long ru_isrss; /* integral unshared stack size */
long ru_minflt; /* page reclaims */
long ru_majflt; /* page faults */
long ru_nswap; /* swaps */
long ru_inblock; /* block input operations */
long ru_oublock; /* block output operations */
long ru_msgsnd; /* messages sent */
long ru_msgrcv; /* messages received */
long ru_nsignals; /* signals received */
long ru_nvcsw; /* voluntary context switches */
long ru_nivcsw; /* involuntary context switches */
};
The fields are interpreted as follows:
Fa ru_utime
the total amount of time spent executing in user mode.
Fa ru_stime
the total amount of time spent in the system executing on behalf
of the process(es).
Fa ru_maxrss
the maximum resident set size utilized (in kilobytes).
Fa 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 * ticks-of-execution.
Ticks are statistics clock ticks.
The statistics clock has a frequency of
sysconf (_SC_CLK_TCK);
ticks per second.
Fa ru_idrss
an integral value of the amount of unshared memory residing in the
data segment of a process (expressed in units of
kilobytes * ticks-of-execution).
Fa ru_isrss
an integral value of the amount of unshared memory residing in the
stack segment of a process (expressed in units of
kilobytes * ticks-of-execution).
Fa 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.
Fa ru_majflt
the number of page faults serviced that required I/O activity.
Fa ru_nswap
the number of times a process was
``swapped''
out of main
memory.
Fa ru_inblock
the number of times the file system had to perform input.
Fa ru_oublock
the number of times the file system had to perform output.
Fa ru_msgsnd
the number of IPC messages sent.
Fa ru_msgrcv
the number of IPC messages received.
Fa ru_nsignals
the number of signals delivered.
Fa 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).
Fa 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
Fa ru_inblock
and
Fa 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.
RETURN VALUES
Rv -std getrusage
ERRORS
The
getrusage ();
system call will fail if:
Bq Er EINVAL
The
Fa who
argument is not a valid value.
Bq Er EFAULT
The address specified by the
Fa rusage
argument is not in a valid part of the process address space.
