gprof
生成函数调用关系以及调用次数，并统计耗时。用于优化代码或发现隐藏的问题。
示例
示例代码
1 #include <stdio.h> 2 3 void FunB() 4 { 5 int a = 1; 6 int b = 2; 7 int c; 8 for(int i = 0; i < 100000000; ++i) { 9 c = a / b; 10 } 11 } 12 13 void FunA() 14 { 15 int a = 1; 16 int b = 2; 17 int c; 18 for(int i = 0; i < 100000000; ++i) { 19 c = a + b; 20 } 21 FunB(); 22 } 23 24 int main() 25 { 26 FunA(); 27 return 0; 28 }
编译程序（编译选项/链接选项都要添加”-pg“）
g++ -o a.out test.cpp -pg
运行程序
./a.out
分析程序
gprof a.out gmon.out > report
其中gmon.out为运行程序后生成的辅助文件（注意：程序需要正常退出结束），打开report文件
1 Flat profile: 2 3 Each sample counts as 0.01 seconds. 4 % cumulative self self total 5 time seconds seconds calls ms/call ms/call name 6 68.97 0.23 0.23 1 234.51 234.51 FunB() 7 26.99 0.33 0.09 1 91.76 326.27 FunA() 8 9 % the percentage of the total running time of the 10 time program used by this function. 11 12 cumulative a running sum of the number of seconds accounted 13 seconds for by this function and those listed above it. 14 15 self the number of seconds accounted for by this 16 seconds function alone. This is the major sort for this 17 listing. 18 19 calls the number of times this function was invoked, if 20 this function is profiled, else blank. 21 22 self the average number of milliseconds spent in this 23 ms/call function per call, if this function is profiled, 24 else blank. 25 26 total the average number of milliseconds spent in this 27 ms/call function and its descendents per call, if this 28 function is profiled, else blank. 29 30 name the name of the function. This is the minor sort 31 for this listing. The index shows the location of 32 the function in the gprof listing. If the index is 33 in parenthesis it shows where it would appear in 34 the gprof listing if it were to be printed. 35 36 37 Copyright (C) 2012-2019 Free Software Foundation, Inc. 38 39 Copying and distribution of this file, with or without modification, 40 are permitted in any medium without royalty provided the copyright 41 notice and this notice are preserved. 42 43 44 Call graph (explanation follows) 45 46 47 granularity: each sample hit covers 2 byte(s) for 3.06% of 0.33 seconds 48 49 index % time self children called name 50 <spontaneous> 51 [1] 100.0 0.00 0.33 main [1] 52 0.09 0.23 1/1 FunA() [2] 53 ----------------------------------------------- 54 0.09 0.23 1/1 main [1] 55 [2] 100.0 0.09 0.23 1 FunA() [2] 56 0.23 0.00 1/1 FunB() [3] 57 ----------------------------------------------- 58 0.23 0.00 1/1 FunA() [2] 59 [3] 71.9 0.23 0.00 1 FunB() [3] 60 ----------------------------------------------- 61 62 This table describes the call tree of the program, and was sorted by 63 the total amount of time spent in each function and its children. 64 65 Each entry in this table consists of several lines. The line with the 66 index number at the left hand margin lists the current function. 67 The lines above it list the functions that called this function, 68 and the lines below it list the functions this one called. 69 This line lists: 70 index A unique number given to each element of the table. 71 Index numbers are sorted numerically. 72 The index number is printed next to every function name so 73 it is easier to look up where the function is in the table. 74 75 % time This is the percentage of the `total' time that was spent 76 in this function and its children. Note that due to 77 different viewpoints, functions excluded by options, etc, 78 these numbers will NOT add up to 100%. 79 80 self This is the total amount of time spent in this function. 81 82 children This is the total amount of time propagated into this 83 function by its children. 84 85 called This is the number of times the function was called. 86 If the function called itself recursively, the number 87 only includes non-recursive calls, and is followed by 88 a `+' and the number of recursive calls. 89 90 name The name of the current function. The index number is 91 printed after it. If the function is a member of a 92 cycle, the cycle number is printed between the 93 function's name and the index number. 94 95 96 For the function's parents, the fields have the following meanings: 97 98 self This is the amount of time that was propagated directly 99 from the function into this parent. 100 101 children This is the amount of time that was propagated from 102 the function's children into this parent. 103 104 called This is the number of times this parent called the 105 function `/' the total number of times the function 106 was called. Recursive calls to the function are not 107 included in the number after the `/'. 108 109 name This is the name of the parent. The parent's index 110 number is printed after it. If the parent is a 111 member of a cycle, the cycle number is printed between 112 the name and the index number. 113 114 If the parents of the function cannot be determined, the word 115 `<spontaneous>' is printed in the `name' field, and all the other 116 fields are blank. 117 118 For the function's children, the fields have the following meanings: 119 120 self This is the amount of time that was propagated directly 121 from the child into the function. 122 123 children This is the amount of time that was propagated from the 124 child's children to the function. 125 126 called This is the number of times the function called 127 this child `/' the total number of times the child 128 was called. Recursive calls by the child are not 129 listed in the number after the `/'. 130 131 name This is the name of the child. The child's index 132 number is printed after it. If the child is a 133 member of a cycle, the cycle number is printed 134 between the name and the index number. 135 136 If there are any cycles (circles) in the call graph, there is an 137 entry for the cycle-as-a-whole. This entry shows who called the 138 cycle (as parents) and the members of the cycle (as children.) 139 The `+' recursive calls entry shows the number of function calls that 140 were internal to the cycle, and the calls entry for each member shows, 141 for that member, how many times it was called from other members of 142 the cycle. 143 144 145 Copyright (C) 2012-2019 Free Software Foundation, Inc. 146 147 Copying and distribution of this file, with or without modification, 148 are permitted in any medium without royalty provided the copyright 149 notice and this notice are preserved. 150 151 152 Index by function name 153 154 [2] FunA() [3] FunB()
