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GETRUSAGE(2)		 DragonFly System Calls Manual		  GETRUSAGE(2)

NAME

getrusage -- get information about resource utilization

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/types.h> #include <sys/time.h> #include <sys/resource.h> #define RUSAGE_SELF 0 #define RUSAGE_CHILDREN -1 int getrusage(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 parame- ter is either RUSAGE_SELF or RUSAGE_CHILDREN. The buffer to which 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: 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 by the text segment that was also shared among other pro- cesses. 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_CLOCK_TCK) ticks per second. 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). 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). 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 activ- ity. 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 caching mechanism is charged only to the first process to read or write the data.

RETURN VALUES

The getrusage() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

The getrusage() function will fail if: [EINVAL] The who parameter is not a valid value. [EFAULT] The address specified by the rusage parameter is not in a valid part of the process address space.

SEE ALSO

gettimeofday(2), wait(2), clocks(7)

HISTORY

The getrusage() function call appeared in 4.2BSD.

BUGS

There is no way to obtain information about a child process that has not yet terminated. DragonFly 4.1 June 4, 1993 DragonFly 4.1