getrusage()函式 Unix/Linux


getrusage - 得到的資源使用情況

內容簡介

#include <sys/time.h> 
#include <sys/resource.h>

int getrusage(int who, struct rusage *usage);

描述

getrusage() 返回當前資源使用,對於無論是 RUSAGE_SELF 或 RUSAGE_CHILDREN. 前者要求所使用當前進程,後者所使用的那些其子已經終止,並且已經在等待資源的資源。

struct rusage {
    struct timeval ru_utime; /* user time used */
    struct timeval ru_stime; /* system 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 */
    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 */
};

返回值

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

錯誤

標籤 描述
EFAULT usage points outside the accessible address space.
EINVAL who is invalid.

遵循於

SVr4, 4.3BSD. POSIX.1-2001 specifies getrusage(), but only specifies the fields ru_utimeand ru_stime.

注意

Including <sys/time.h> is not required these days, but increases portability. (Indeed,struct timeval is defined in <sys/time.h>.)

In Linux kernel versions before 2.6.9, if the disposition of SIGCHLD is set to SIG_IGNthen the resource usages of child processes are automatically included in the value returned by RUSAGE_CHILDREN, although POSIX.1-2001 explicitly prohibits this. This non-conformance is rectified in Linux 2.6.9 and later.

The above struct was taken from 4.3BSD Reno. Not all fields are meaningful under Linux. In linux 2.4 only the fields ru_utimeru_stimeru_minflt, and ru_majflt are maintained. Since Linux 2.6, ru_nvcsw and ru_nivcsw are also maintained.

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