simple parallel processing in windows

玩data mining有個好處就是在處理大量資料的時候可以盡情的加速...do as whatever you can do :)

所以現在在coding的時候發現可以加速的地方都會加速..

so 底下提供一些sample, 把你要parallel的指令放入一個list, 然後call c_parallen()就可以達到parallel.

如果用MinGW 記得加上 -mwindows
windows.h記得include

1. #define UNICODE
2. 
   
3. #include <windows.h>
4. #include <iostream>
5. #include <vector>
6. 
   
7. using namespace std;
8. 
   
9. PROCESS_INFORMATION* c_fork(const char * cmd){
10. 
    
11. STARTUPINFO si;
12. PROCESS_INFORMATION *pi = (PROCESS_INFORMATION*)malloc(sizeof(PROCESS_INFORMATION) );
13. 
    
14. ZeroMemory( &si, sizeof(si) );
15. si.cb = sizeof(si);
16. ZeroMemory( pi, sizeof(PROCESS_INFORMATION) );
17. 
    
18. TCHAR Tcmd [4096];
19. mbstowcs(Tcmd, cmd, (sizeof(TCHAR) * strlen(cmd) ));
20. 
    
21. 
    
22. 
    
23. // Start the child process.
24. if( !CreateProcess( NULL, // No module name (use command line)
25. Tcmd, // Command line
26. NULL, // Process handle not inheritable
27. NULL, // Thread handle not inheritable
28. FALSE, // Set handle inheritance to FALSE
29. 0, // No creation flags
30. NULL, // Use parent's environment block
31. NULL, // Use parent's starting directory
32. &si, // Pointer to STARTUPINFO structure
33. pi ) // Pointer to PROCESS_INFORMATION structure
34. )
35. {
36. printf( "CreateProcess failed (%d)\n", GetLastError() );
37. return NULL;
38. }
39. 
    
40. return pi;
41. }
42. 
    
43. void c_parallel(const char* cmdlist){
44. 
    
45. ifstream in(cmdlist, ios::binary);
46. string line;
47. vector<PROCESS_INFORMATION*> process;
48. while( ! in.eof()){
49. 
    
50. getline(in, line);
51. 
    
52. if( !line.empty() ){
53. 
    
54. cout << "do:" << line << endl;
55. process.push_back( c_fork( line.c_str() )) ;
56. 
    
57. 
    
58. }
59. 
    
60. }
61. //joint
62. for(int i=0; i < process.size(); i++){
63. WaitForSingleObject( process[i]->hProcess, INFINITE );
64. }
65. //close
66. for(int i=0; i < process.size(); i++){
67. CloseHandle( process[i]->hProcess );
68. CloseHandle( process[i]->hThread );
69. free(process[i]);
70. }
71. }