Linux 系統調用sysconf

一、前言

　　當前計算機都是多核的，linux2.6提供了進程綁定cpu功能，將進程指定到某個core上執行，方便管理進程。linux提供了sysconf系統調用能夠獲取系統的cpu個數和可用的cpu個數。

二、sysconf  函數

　　man一下sysconf，解釋這個函數用來獲取系統執行的配置信息。例如頁大小、最大頁數、cpu個數、打開句柄的最大個數等等。詳細說明能夠參考man。

三、測試程序

　　寫一個測試程序，方便往後使用。

#include <stdio.h>
#include <unistd.h>

#define ONE_MB (1024 * 1024)

int main()
{
    printf("The number of processors configured is :%ld\n",
        sysconf(_SC_NPROCESSORS_CONF));
    printf("The number of processors currently online (available) is :%ld\n",
        sysconf(_SC_NPROCESSORS_ONLN));
    printf ("The pagesize: %ld\n", sysconf(_SC_PAGESIZE));
    printf ("The number of pages: %ld\n", sysconf(_SC_PHYS_PAGES));
    printf ("The number of available pages: %ld\n", sysconf(_SC_AVPHYS_PAGES));
    printf ("The memory size: %lld MB\n",
        (long long)sysconf(_SC_PAGESIZE) * (long long)sysconf(_SC_PHYS_PAGES) / ONE_MB );
    printf ("The number of files max opened:: %ld\n", sysconf(_SC_OPEN_MAX));
    printf("The number of ticks per second: %ld\n", sysconf(_SC_CLK_TCK));
    printf ("The max length of host name: %ld\n", sysconf(_SC_HOST_NAME_MAX));
    printf ("The max length of login name: %ld\n", sysconf(_SC_LOGIN_NAME_MAX));
    return 0;
}

個人虛擬機配置了4個核，1G的內存，32位的linux。執行結果以下：

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