GETRUSAGE(2) GETRUSAGE(2) NAME getrusage - get information about resource utilization SYNOPSIS #include #include #define RUSAGE_SELF 0 /* calling process */ #define RUSAGE_CHILDREN -1 /* terminated child processes */ getrusage(who, rusage) int who; struct rusage *rusage; DESCRIPTION _G_e_t_r_u_s_a_g_e returns information describing the resources utilized by the current process, or all its terminated child processes. The _w_h_o param‐ eter is one of RUSAGE_SELF or RUSAGE_CHILDREN. The buffer to which _r_u_s_a_g_e 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 */ int ru_maxrss; int ru_ixrss; /* integral shared text memory size */ int ru_idrss; /* integral unshared data size */ int ru_isrss; /* integral unshared stack size */ int ru_minflt; /* page reclaims */ int ru_majflt; /* page faults */ int ru_nswap; /* swaps */ int ru_inblock; /* block input operations */ int ru_oublock; /* block output operations */ int ru_msgsnd; /* messages sent */ int ru_msgrcv; /* messages received */ int ru_nsignals; /* signals received */ int ru_nvcsw; /* voluntary context switches */ int 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 processes. This value is expressed in units of kilo‐ bytes * seconds-of-execution and is calculated by sum‐ ming 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 that 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 out‐ put. 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 _r_u__i_n_b_l_o_c_k and _r_u__o_u_t_b_l_o_c_k 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. ERRORS The possible errors for _g_e_t_r_u_s_a_g_e are: [EINVAL] The _w_h_o parameter is not a valid value. [EFAULT] The address specified by the _r_u_s_a_g_e parameter is not in a valid part of the process address space. SEE ALSO gettimeofday(2), wait(2) BUGS There is no way to obtain information about a child process that has not yet terminated. 4th Berkeley Distribution May 13, 1986 GETRUSAGE(2)