我写了一个基本的嬉皮舞 http://www.facebook.com/careers/puzzles.php?puzzle_id=7使用 C、Python 和 OCaml 编写程序。诚然，这可能不是这三种语言的一个很好的基准。但我得到的结果是这样的：

• Python：0.350 秒
• C：0.050秒
• 解释的OCaml：0.040 秒
• 编译的 OCaml：.010

python 的性能并没有真正令我惊讶，但我对 OCaml 的速度（尤其是解释版本）感到相当震惊。为了进行比较，我将发布 C 版本和 OCaml 版本。

C

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

long get_count(char *name);

int main(int argc, char *argv[])
{
  if (argc != 2){
    printf("Filename must be specified as a positional argument.\n");
    exit(EXIT_FAILURE);
  }

  long count_no = get_count(argv[1]);

  int i;
  for (i = 1; i <= count_no; i++){
    if (((i % 3) == 0) && ((i % 5) == 0)){
      printf("Hop\n");
      continue;
    }
    if ((i % 3) == 0){
      printf("Hoppity\n");
    }
    if ((i % 5) == 0){
      printf("Hophop\n");
    }
  }
  return 0;
}

long get_count(char *name){
  FILE *fileptr = fopen(name, "r");
  if (!fileptr){
    printf("Unable to open file %s.\n", name);
    exit(EXIT_FAILURE);
  }
  size_t text_len = 20;
  char *file_text = calloc(text_len, sizeof(char));
  while (!feof(fileptr)){
    fread(file_text, sizeof(char), text_len, fileptr);
    assert(!ferror(fileptr));
    text_len += 20;
    file_text = realloc(file_text, text_len * sizeof(char));
  }
  long file_as_int = strtol(file_text, NULL, 10);

  free(file_text);
  return file_as_int;
}

OCaml

open String;;

let trim str =
  if str = "" then "" else
  let search_pos init p next =
    let rec search i =
      if p i then raise(Failure "empty") else
      match str.[i] with
      | ' ' | '\n' | '\r' | '\t' -> search (next i)
      | _ -> i
    in
    search init
  in
  let len = String.length str in
  try
    let left = search_pos 0 (fun i -> i >= len) (succ)
    and right = search_pos (len - 1) (fun i -> i < 0) (pred)
    in
    String.sub str left (right - left + 1)
  with
  | Failure "empty" -> ""
;;

let rec iterate_over_numbers curr_num max_num =
  (
   if curr_num <= max_num then (
     if ((curr_num mod 3) == 0) && ((curr_num mod 5) == 0) then 
       print_endline "Hop"
     else if (curr_num mod 3) == 0 then 
       print_endline "Hoppity"
     else if (curr_num mod 5) == 0 then
       print_endline "Hophop";
     iterate_over_numbers (curr_num + 1) max_num
   ))
;;


let fname = Sys.argv.(1);;
let infile = open_in fname;;
let file_text = trim (input_line infile);;
close_in infile;;
let input_number = int_of_string file_text;;
iterate_over_numbers 1 input_number;;

但我很好奇为什么会得到这些结果。我在我的 C 程序中做了一些愚蠢的事情，还是这只是 OCaml 更快的事情？在我看来有点奇怪，解释型程序的运行速度比 C 版本快一点，而编译型程序的运行速度是 C 版本的 5 倍。

您的 C 代码并不等同于 OCaml 代码 - 您在 OCaml 中使用了“else if”以避免需要重新计算太多模数。

“读取长整数”中有大量代码。为什么不直接使用fscanf();它会自动跳过空白和所有内容，并避免您执行malloc()等等，我不经常推荐使用fscanf()，但这看起来像是一个设置 - 一行，可能两边都有空格，没有有趣的东西。

好奇害死猫——但在这种情况下，不是豹子。

我下载了适用于MacOS X Intel的OCaml 3.11.1，并将问题中的OCaml代码复制到xxx.ml（OCaml）中，并将其编译成目标文件xxx（使用“ocamlc -o xxx xxx.ml”）；我将 C 代码逐字复制到 yyy.c 中，并使用以下命令创建了一个变体 zzz.cfscanf() and fclose()，并使用“gcc -O -o yyy yyy.c”和“gcc -O -o zzz zzz.c”编译它们。我创建了一个文件“file3”，其中包含：“987654"加上一个换行符。我创建了一个 shell 脚本 runthem.sh 如图所示。请注意，'time' 是一个讨厌的命令，它认为它的输出必须发送到 stderr，即使您不希望它不发送 - 您必须非常努力地工作将输出获取到您想要的位置。（range 命令生成给定范围内的数字，包括在内 - 因此每个程序有 11 个值。）

Osiris JL: cat runthem.sh
for prog in "ocaml xxx.ml" ./xxx ./yyy ./zzz
do
    for iter in $(range 0 10)
    do
        r=$(sh -c "time $prog file3 >/dev/null" 2>&1)
        echo $prog: $r
    done
done
Osiris JL: 

我在运行 Leopard (10.5.8) 的现代 MacBook Pro（3 GHz Core 2 Duo 等，4GB RAM）上运行了所有这些。我得到的时间显示如下：

Osiris JL: sh runthem.sh
ocaml xxx.ml: real 0m0.961s user 0m0.524s sys 0m0.432s
ocaml xxx.ml: real 0m0.953s user 0m0.516s sys 0m0.430s
ocaml xxx.ml: real 0m0.959s user 0m0.517s sys 0m0.431s
ocaml xxx.ml: real 0m0.951s user 0m0.517s sys 0m0.430s
ocaml xxx.ml: real 0m0.952s user 0m0.516s sys 0m0.431s
ocaml xxx.ml: real 0m0.952s user 0m0.514s sys 0m0.431s
ocaml xxx.ml: real 0m0.951s user 0m0.515s sys 0m0.431s
ocaml xxx.ml: real 0m0.959s user 0m0.515s sys 0m0.431s
ocaml xxx.ml: real 0m0.950s user 0m0.515s sys 0m0.431s
ocaml xxx.ml: real 0m0.956s user 0m0.516s sys 0m0.431s
ocaml xxx.ml: real 0m0.952s user 0m0.514s sys 0m0.432s
./xxx: real 0m0.928s user 0m0.494s sys 0m0.430s
./xxx: real 0m0.938s user 0m0.494s sys 0m0.430s
./xxx: real 0m0.927s user 0m0.494s sys 0m0.430s
./xxx: real 0m0.928s user 0m0.492s sys 0m0.430s
./xxx: real 0m0.928s user 0m0.493s sys 0m0.430s
./xxx: real 0m0.927s user 0m0.493s sys 0m0.430s
./xxx: real 0m0.928s user 0m0.492s sys 0m0.430s
./xxx: real 0m0.933s user 0m0.497s sys 0m0.428s
./xxx: real 0m0.926s user 0m0.494s sys 0m0.429s
./xxx: real 0m0.921s user 0m0.492s sys 0m0.428s
./xxx: real 0m0.925s user 0m0.494s sys 0m0.428s
./yyy: real 0m0.027s user 0m0.026s sys 0m0.001s
./yyy: real 0m0.031s user 0m0.026s sys 0m0.002s
./yyy: real 0m0.028s user 0m0.026s sys 0m0.001s
./yyy: real 0m0.029s user 0m0.026s sys 0m0.002s
./yyy: real 0m0.028s user 0m0.026s sys 0m0.001s
./yyy: real 0m0.029s user 0m0.026s sys 0m0.002s
./yyy: real 0m0.028s user 0m0.026s sys 0m0.001s
./yyy: real 0m0.031s user 0m0.026s sys 0m0.002s
./yyy: real 0m0.028s user 0m0.026s sys 0m0.001s
./yyy: real 0m0.030s user 0m0.026s sys 0m0.002s
./yyy: real 0m0.028s user 0m0.026s sys 0m0.001s
./zzz: real 0m0.030s user 0m0.027s sys 0m0.002s
./zzz: real 0m0.029s user 0m0.027s sys 0m0.001s
./zzz: real 0m0.030s user 0m0.027s sys 0m0.002s
./zzz: real 0m0.029s user 0m0.027s sys 0m0.001s
./zzz: real 0m0.030s user 0m0.027s sys 0m0.002s
./zzz: real 0m0.029s user 0m0.027s sys 0m0.001s
./zzz: real 0m0.030s user 0m0.027s sys 0m0.002s
./zzz: real 0m0.029s user 0m0.027s sys 0m0.001s
./zzz: real 0m0.030s user 0m0.027s sys 0m0.002s
./zzz: real 0m0.029s user 0m0.027s sys 0m0.001s
./zzz: real 0m0.030s user 0m0.027s sys 0m0.002s
Osiris JL:

我没有看到 OCaml 代码比 C 代码运行得更快。我在读取的文件中使用较小的数字运行了测试，结果同样有利于 C 代码：

停靠站号码：345

ocaml xxx.ml: real 0m0.027s user 0m0.020s sys 0m0.005s
ocaml xxx.ml: real 0m0.021s user 0m0.016s sys 0m0.005s
ocaml xxx.ml: real 0m0.025s user 0m0.016s sys 0m0.004s
ocaml xxx.ml: real 0m0.020s user 0m0.015s sys 0m0.003s
ocaml xxx.ml: real 0m0.022s user 0m0.016s sys 0m0.004s
ocaml xxx.ml: real 0m0.019s user 0m0.015s sys 0m0.003s
ocaml xxx.ml: real 0m0.021s user 0m0.016s sys 0m0.004s
ocaml xxx.ml: real 0m0.020s user 0m0.015s sys 0m0.004s
ocaml xxx.ml: real 0m0.021s user 0m0.016s sys 0m0.004s
ocaml xxx.ml: real 0m0.020s user 0m0.015s sys 0m0.004s
ocaml xxx.ml: real 0m0.021s user 0m0.016s sys 0m0.004s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.002s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.002s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.005s user 0m0.001s sys 0m0.002s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.002s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./xxx: real 0m0.003s user 0m0.001s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.003s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.001s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.002s user 0m0.000s sys 0m0.001s
./yyy: real 0m0.003s user 0m0.000s sys 0m0.002s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.001s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.003s user 0m0.000s sys 0m0.002s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s
./zzz: real 0m0.002s user 0m0.000s sys 0m0.001s

停靠站号码：87654

ocaml xxx.ml: real 0m0.102s user 0m0.059s sys 0m0.041s
ocaml xxx.ml: real 0m0.102s user 0m0.059s sys 0m0.040s
ocaml xxx.ml: real 0m0.101s user 0m0.060s sys 0m0.040s
ocaml xxx.ml: real 0m0.103s user 0m0.059s sys 0m0.041s
ocaml xxx.ml: real 0m0.102s user 0m0.059s sys 0m0.041s
ocaml xxx.ml: real 0m0.101s user 0m0.059s sys 0m0.041s
ocaml xxx.ml: real 0m0.102s user 0m0.059s sys 0m0.040s
ocaml xxx.ml: real 0m0.103s user 0m0.059s sys 0m0.040s
ocaml xxx.ml: real 0m0.101s user 0m0.059s sys 0m0.040s
ocaml xxx.ml: real 0m0.102s user 0m0.059s sys 0m0.040s
ocaml xxx.ml: real 0m0.105s user 0m0.059s sys 0m0.041s
./xxx: real 0m0.092s user 0m0.044s sys 0m0.038s
./xxx: real 0m0.087s user 0m0.044s sys 0m0.039s
./xxx: real 0m0.085s user 0m0.044s sys 0m0.038s
./xxx: real 0m0.084s user 0m0.044s sys 0m0.038s
./xxx: real 0m0.085s user 0m0.044s sys 0m0.039s
./xxx: real 0m0.086s user 0m0.045s sys 0m0.039s
./xxx: real 0m0.085s user 0m0.044s sys 0m0.039s
./xxx: real 0m0.085s user 0m0.044s sys 0m0.038s
./xxx: real 0m0.084s user 0m0.044s sys 0m0.038s
./xxx: real 0m0.084s user 0m0.044s sys 0m0.039s
./xxx: real 0m0.083s user 0m0.044s sys 0m0.038s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.005s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.005s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.004s user 0m0.003s sys 0m0.001s
./yyy: real 0m0.006s user 0m0.003s sys 0m0.002s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.005s user 0m0.003s sys 0m0.002s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.004s user 0m0.003s sys 0m0.001s
./zzz: real 0m0.005s user 0m0.003s sys 0m0.001s

显然，YMMV - 但 OCaml 似乎比 C 慢很多，但如果给定文件中的数量足够小，则启动和文件读取将主导处理时间。

C 计时，特别是在较小数字时，速度太快，以至于不太可靠。