設定線程的親緣性，多線程編程

在openmp中有個比較典型的測試例子cpp_compiler_options_openmp.cpp，展示了

for迴圈中的歸約操作， #pragma omp parallel for reduction(+:sum) private(x) 

自已也寫個多線程的版本，針對Intel Core 2 Duo CPU.

計算pi的方法很多，這個方法用於測試最好了，原理：http://wenku.baidu.com/view/3287baacdd3383c4bb4cd2ed.html

c代碼：

double test1(int num_steps) {   int i;   double x, pi, sum = 0.0, step;   step = 1.0 / (double) num_steps;   for (i = 1; i <= num_steps; i++) {      x = (i - 0.5) * step;      sum = sum + 4.0 / (1.0 + x*x);   }   pi = step * sum;   return pi;}

使用MS vc++6.0 編譯，得到FPU單線程版本。

用Intel C++編譯，得到SSE單線程版本。

用Intel C++結合openmp產生SSE的3線程版本(兩個計算線程，一個主線程)。

我將Intel C++編譯，得到SSE單線程版本改寫為如上的3線程版本。

 

處理器：Intel Core(TM)2 Duo CPU E8500 @3.16GHz 3.16GHz  win7 32位.

效能如下：

MS VC    For 1000000000 steps, pi = 3.141592653589971, 6506 milliseconds  單線程

Intel C++ For 1000000000 steps, pi = 3.141592653589763, 3307 milliseconds  單線程

Openmp+Intel C++ For 1000000000 steps, pi = 3.141592653589738, 1684 milliseconds 3線程

my mtTest.exe  For 1000000000 steps, pi = 3.141592653589738 ,1606 milliseconds 3線程

很容易擴充成更多的線程。

 

;>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>;*--==--* fasm  multiple threads.;*--==--* By G-Spider;*--==--* fasm mtTest.asm mtTest.exe;>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>format PE consoleentry startinclude 'win32a.inc'THREAD_PRIORITY_TIME_CRITICAL = 0fhTHREAD_PRIORITY_HIGHEST = 02hCREATE_SUSPENDED = 04hINFINITE = -1;i = 1; i <= num_steps; i++;[1 , N/2] [N/2+1, N]N = 1000000000;---------------------------------------------section '.text' code readable executable  start:     invoke GetCurrentThread     mov edi,eax     invoke SetThreadPriority,edi,THREAD_PRIORITY_TIME_CRITICAL     invoke SetThreadAffinityMask,edi,1;==============================================================          invoke GetTickCount     mov ebx,eax     xor esi,esi @@:      xor eax,eax     lea edx,[esi*8+dwParam]     invoke CreateThread,eax,eax,ThreadProc,edx,CREATE_SUSPENDED,eax     test eax,eax     jz _END     mov [hTrd+esi*4],eax        mov edi,eax     invoke SetThreadPriority,edi,THREAD_PRIORITY_HIGHEST     inc esi     invoke SetThreadAffinityMask,edi,esi     invoke ResumeThread,edi          test esi,1     jnz @B      invoke WaitForMultipleObjects,2,hTrd,TRUE,INFINITE      invoke GetTickCount     sub eax,ebx;==============================================================     push eax      sub esp,8     fld qword [dwParam+16]     fadd qword [dwParam+24]     fstp qword [esp]     push szFmt     call [printf]     add esp,16     cinvoke system,szPause_END:          invoke ExitProcess,0;align  16     proc ThreadProc  uses esi, lpParam     mov esi,[lpParam]     stdcall _testPiSSE,[esi],[esi+4]     fstp qword [esi+16]     retendp  align  16_testPiSSE:; parameter 1: 8 + ebp  ;lower; parameter 2: 12 + ebp ;higher.B2.1:                          ; Preds .B2.0        push      ebp                                               mov       ebp, esp                                            and       esp, -16                                              push      ebx                                                 sub       esp, 28                                             mov       eax, dword [8+ebp]                               mov       ecx, dword [12+ebp]                             cmp       eax, ecx                                            jg        .B2.10        ; Prob 50%                   .B2.2:                          ; Preds .B2.1        sub       ecx, eax                                            inc       ecx                                                   cmp       ecx, 8                                               jl        .B2.12        ; Prob 10%              .B2.3:                          ; Preds .B2.2        mov       ebx, 2                                      mov       edx, ecx                                           and       edx, 7                                              neg       edx                                                 pxor      xmm1, xmm1                                          pxor      xmm6, xmm6                                        add       edx, ecx                                            movd      xmm3, ebx                                    lea       ebx, dword [1+eax]                 pshufd    xmm4, xmm3, 0                        movd      xmm3, eax                               movaps    xmm5, dqword [_2il0floatpacket.13]         movaps    xmm2, dqword [_2il0floatpacket.14]           movd      xmm0, ebx                                    xor       ebx, ebx                                 punpckldq xmm3, xmm0                                movaps    xmm0, xmm6                             punpcklqdq xmm3, xmm1                      .B2.4:                          ; Preds .B2.4 .B2.3        cvtdq2pd  xmm7, xmm3                              subpd     xmm7, xmm2                     mulpd     xmm7, xmm5                              mulpd     xmm7, xmm7                           movaps    xmm1, dqword [_2il0floatpacket.16]         paddd     xmm3, xmm4                             addpd     xmm7, xmm1                              movaps    dqword [esp], xmm0                               add       ebx, 8                                movaps    xmm0, dqword [_2il0floatpacket.15]            cmp       ebx, edx                                     divpd     xmm0, xmm7                        cvtdq2pd  xmm7, xmm3                              addpd     xmm6, xmm0                           subpd     xmm7, xmm2                        mulpd     xmm7, xmm5                            mulpd     xmm7, xmm7                               addpd     xmm7, xmm1                              movaps    xmm0, dqword [_2il0floatpacket.15]             paddd     xmm3, xmm4                                   divpd     xmm0, xmm7                                 movaps    xmm7, dqword [esp]                       addpd     xmm7, xmm0                          cvtdq2pd  xmm0, xmm3                  subpd     xmm0, xmm2                               mulpd     xmm0, xmm5                               mulpd     xmm0, xmm0                           addpd     xmm0, xmm1                             movaps    dqword [esp], xmm7                   paddd     xmm3, xmm4                                movaps    xmm7, dqword [_2il0floatpacket.15]          divpd     xmm7, xmm0                                cvtdq2pd  xmm0, xmm3                                 addpd     xmm6, xmm7                            subpd     xmm0, xmm2                                 mulpd     xmm0, xmm5                            mulpd     xmm0, xmm0                            addpd     xmm0, xmm1                              movaps    xmm1, dqword [_2il0floatpacket.15]             paddd     xmm3, xmm4                               divpd     xmm1, xmm0                              movaps    xmm0, dqword [esp]                    addpd     xmm0, xmm1                              jb        .B2.4         ; Prob 82%.B2.5:                          ; Preds .B2.4        addpd     xmm6, xmm0                             movaps    xmm0, xmm6                              unpckhpd  xmm0, xmm6                          addsd     xmm6, xmm0              .B2.6:                          ; Preds .B2.5 .B2.12        movsd     xmm2, qword [_2il0floatpacket.12]        add       eax, edx                                              cmp       edx, ecx                               jae       .B2.11        ; Prob 10%               .B2.7:                          ; Preds .B2.6        movsd     xmm1, qword [_2il0floatpacket.17]             movsd     xmm0, qword [_2il0floatpacket.19]      .B2.8:                          ; Preds .B2.8 .B2.7        pxor      xmm3, xmm3                                      inc       edx                                       cvtsi2sd  xmm3, eax                                     movsd     xmm4, qword [_2il0floatpacket.18]              inc       eax                                         cmp       edx, ecx                                        subsd     xmm3, xmm1                                   mulsd     xmm3, xmm2                                  mulsd     xmm3, xmm3                                     addsd     xmm3, xmm0                                    divsd     xmm4, xmm3                                  addsd     xmm6, xmm4                              jb        .B2.8         ; Prob 82%                       jmp       .B2.11        ; Prob 100%        .B2.10:                         ; Preds .B2.1        movsd     xmm2, qword [_2il0floatpacket.12]             pxor      xmm6, xmm6                            .B2.11:                         ; Preds .B2.8 .B2.6 .B2.10        mulsd     xmm2, xmm6                                           movsd     qword [esp], xmm2                      fld       qword [esp]                           add       esp, 28                                 pop       ebx                                       mov       esp, ebp                               pop       ebp                                       retn 8                                       .B2.12:                         ; Preds .B2.2                    xor       edx, edx                                  pxor      xmm6, xmm6                                    jmp       .B2.6         ; Prob 100%            ;---------------------------------------------section '.data' data readable writeable_2il0floatpacket.13DD0e826d695H,03e112e0bH,0e826d695H,03e112e0bH_2il0floatpacket.14DD000000000H,03fe00000H,000000000H,03fe00000H_2il0floatpacket.15DD000000000H,040100000H,000000000H,040100000H_2il0floatpacket.16DD000000000H,03ff00000H,000000000H,03ff00000H_2il0floatpacket.12DD0e826d695H,03e112e0bH  ;N=1000000000_2il0floatpacket.17DD000000000H,03fe00000H  ;0.5   _2il0floatpacket.18DD000000000H,040100000H  ;4.0_2il0floatpacket.19DD000000000H,03ff00000H  ;1.0dwParam dd 1,N/2-1000,N/2+1-1000,N,0,0,0,0hTrd    rd 2  szFmt   db '%.15lf ,%d ms', 0aH, 00HszPause db 'pause',0;---------------------------------------------section '.idata' import data readable writeable  library kernel32,'KERNEL32.DLL',\    msvcrt,'msvcrt.dll'       include 'api\kernel32.inc'       import msvcrt,\     printf,'printf',\     system,'system'