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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | NOTES | SEE ALSO | COLOPHON |
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getrusage(2) System Calls Manual getrusage(2)
getrusage - get resource usage
Standard C library (libc, -lc)
#include <sys/resource.h>
int getrusage(int who, struct rusage *usage);
getrusage() returns resource usage measures for who, which can be
one of the following:
RUSAGE_SELF
Return resource usage statistics for the calling process,
which is the sum of resources used by all threads in the
process.
RUSAGE_CHILDREN
Return resource usage statistics for all children of the
calling process that have terminated and been waited for.
These statistics will include the resources used by
grandchildren, and further removed descendants, if all of
the intervening descendants waited on their terminated
children.
RUSAGE_THREAD (since Linux 2.6.26)
Return resource usage statistics for the calling thread.
The _GNU_SOURCE feature test macro must be defined (before
including any header file) in order to obtain the
definition of this constant from <sys/resource.h>.
The resource usages are returned in the structure pointed to by
usage, which has the following form:
struct rusage {
struct timeval ru_utime; /* user CPU time used */
struct timeval ru_stime; /* system CPU time used */
long ru_maxrss; /* maximum resident set size */
long ru_ixrss; /* integral shared memory size */
long ru_idrss; /* integral unshared data size */
long ru_isrss; /* integral unshared stack size */
long ru_minflt; /* page reclaims (soft page faults) */
long ru_majflt; /* page faults (hard page faults) */
long ru_nswap; /* swaps */
long ru_inblock; /* block input operations */
long ru_oublock; /* block output operations */
long ru_msgsnd; /* IPC messages sent */
long ru_msgrcv; /* IPC messages received */
long ru_nsignals; /* signals received */
long ru_nvcsw; /* voluntary context switches */
long ru_nivcsw; /* involuntary context switches */
};
Not all fields are completed; unmaintained fields are set to zero
by the kernel. (The unmaintained fields are provided for
compatibility with other systems, and because they may one day be
supported on Linux.) The fields are interpreted as follows:
ru_utime
This is the total amount of time spent executing in user
mode, expressed in a timeval structure (seconds plus
microseconds).
ru_stime
This is the total amount of time spent executing in kernel
mode, expressed in a timeval structure (seconds plus
microseconds).
ru_maxrss (since Linux 2.6.32)
This is the maximum resident set size used (in kilobytes).
For RUSAGE_CHILDREN, this is the resident set size of the
largest child, not the maximum resident set size of the
process tree.
ru_ixrss (unmaintained)
This field is currently unused on Linux.
ru_idrss (unmaintained)
This field is currently unused on Linux.
ru_isrss (unmaintained)
This field is currently unused on Linux.
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 (unmaintained)
This field is currently unused on Linux.
ru_inblock (since Linux 2.6.22)
The number of times the filesystem had to perform input.
ru_oublock (since Linux 2.6.22)
The number of times the filesystem had to perform output.
ru_msgsnd (unmaintained)
This field is currently unused on Linux.
ru_msgrcv (unmaintained)
This field is currently unused on Linux.
ru_nsignals (unmaintained)
This field is currently unused on Linux.
ru_nvcsw (since Linux 2.6)
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 (since Linux 2.6)
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.
On success, zero is returned. On error, -1 is returned, and
errno is set to indicate the error.
EFAULT usage points outside the accessible address space.
EINVAL who is invalid.
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├─────────────────────────────────────┼───────────────┼─────────┤
│ getrusage() │ Thread safety │ MT-Safe │
└─────────────────────────────────────┴───────────────┴─────────┘
POSIX.1-2008.
POSIX.1 specifies getrusage(), but specifies only the fields
ru_utime and ru_stime.
RUSAGE_THREAD is Linux-specific.
POSIX.1-2001, SVr4, 4.3BSD.
Before Linux 2.6.9, if the disposition of SIGCHLD is set to
SIG_IGN then the resource usages of child processes are
automatically included in the value returned by RUSAGE_CHILDREN,
although POSIX.1-2001 explicitly prohibits this. This
nonconformance is rectified in Linux 2.6.9 and later.
The structure definition shown at the start of this page was
taken from 4.3BSD Reno.
Ancient systems provided a vtimes() function with a similar
purpose to getrusage(). For backward compatibility, glibc (up
until Linux 2.32) also provides vtimes(). All new applications
should be written using getrusage(). (Since Linux 2.33, glibc no
longer provides an vtimes() implementation.)
Resource usage metrics are preserved across an execve(2).
clock_gettime(2), getrlimit(2), times(2), wait(2), wait4(2),
clock(3), proc_pid_stat(5), proc_pid_io(5)
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2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
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man-pages@man7.org
Linux man-pages 6.9.1 2024-05-02 getrusage(2)
Pages that refer to this page: fork(2), getrlimit(2), sigaction(2), syscalls(2), times(2), wait(2), wait4(2), clock(3), pmwebtimerregister(3), proc_pid_io(5), pthreads(7), time(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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