Ubuntu下C语言函数运行时间测试.docVIP

最近突然有必要测试C语言中各个函数的运行时间，于是就有哪些信誉好的足球投注网站了一下，发现有4种方法可以达成测算程序运行时间的目的。 它们分别是使用clock, times, gettimeofday, getrusage来实现的。下面就来逐一介绍，并比较它们的优劣点。程序做的处理很简单，就是填写一个1024*1024的矩阵。#include sys/time.h #include sys/resource.h #include unistd.h #include stdio.h #include time.h #define TEST_BY_CLOCK (char)(0x00) #define TEST_BY_TIMES (char)(0x01) #define TEST_BY_GETTIMEOFDAY (char)(0x02) #define TEST_BY_GETRUSAGE (char)(0x03) #define TEST_METHOD (TEST_BY_GETTIMEOFDAY) #define COORDINATION_X (int)(1024) #define COORDINATION_Y (int)(1024) static int g_Matrix[COORDINATION_X][COORDINATION_Y]; double getTimeval() { struct rusage stRusage; struct timeval stTimeval; if (TEST_METHOD == TEST_BY_GETTIMEOFDAY) { gettimeofday(stTimeval, NULL); } else if (TEST_METHOD == TEST_BY_GETRUSAGE) { getrusage(RUSAGE_SELF, stRusage); stTimeval = stRusage.ru_utime; } return stTimeval.tv_sec + (double)stTimeval.tv_usec*1E-6; } int main() { int i, j; int n = 0; clock_t clockT1, clockT2; double doubleT1, doubleT2; if (TEST_METHOD == TEST_BY_CLOCK) { clockT1 = clock(); } else if (TEST_METHOD == TEST_BY_TIMES) { times(clockT1); } else if (TEST_METHOD == TEST_BY_GETTIMEOFDAY) { doubleT1 = getTimeval(); } else if (TEST_METHOD == TEST_BY_GETRUSAGE) { doubleT1 = getTimeval(); } ****************************************************************************** for (i = 0; i COORDINATION_X; i++) { for (j = 0; j COORDINATION_Y; j++) { g_Matrix[i][j] = i * j; } } ****************************************************************************** if (TEST_METHOD == TEST_BY_CLOCK) { clockT2 = clock(); printf(Time result tested by clock = %10.30f\n, (double)(clockT2 - clockT1)/CLOCKS_PER_SEC); } else if (TEST_METHOD == TEST_BY_TIMES) { times(clockT2); printf(Time result tested by times = %10.30f\n, (double)(clockT2 - clockT1)/sysconf(_SC_CLK_TCK)); } else if (TEST_METHOD == TEST_BY_GETTIMEOFDAY) { doubleT2 = getTimeval(); printf(Time result teste