02_C-C++_osx.indd

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1 C/C++ OpenMP* / 2

2 C/C++ OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* parallel / OpenMP* / 4 1 OpenMP* 2 3 Fortran OpenMP* 4 PC 1

3 bit 64bit Linux* 32bit 64bit Windows* 9.0 OpenMP* OpenMP* 9.0 OpenMP* 2.5 OpenMP* OpenMP* 2

4 2 OpenMP* OS OS CPU Memory CPU CPU CPU OpenMP*.1 PC OS.2 3

5 3OpenMP* OpenMP* APIApplication Programming Interface OpenMP* API 1997 Open MP Architecture Review Board Linux*UNIX* Windows* OpenMP* C/C++ Fortran OpenMP* OpenMP* 9.0 OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* 2.5 C/C++ Fortran 1998 OpenMP* C/C OpenMP* C/C OpenMP* Fortran C/C OpenMP* Fortran OpenMP* Fortran OpenMP* Fortran OpenMP* 3.1 C/C++ Fortran API OpenMP* OpenMP* C/C++ Fortran OpenMP* OpenMP* OpenMP* /Qopenmp Windows*-openmp Linux* OpenMP* OpenMP* OpenMP* OpenMP* 4

6 OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* 32bit 64bit Linux* 32bit 64bit Windows* OpenMP* 3.2 OpenMP* OpenMP* OpenMP* API OpenMP* /.4 OpenMP* OpenMP* API OpenMP* API OpenMP* API OpenMP* API 5

7 OpenMP* OpenMP* OpenMP* for if (n>limit) default (none) shared (n,a,b,c,x,y,z) private(f,i,scale) f = 1.0; #pragma omp for nowait for (i=0; i<n; i++) z[i] = x[i] + y[i]; Parallel Region #pragma omp for nowait for (i=0; i<n; i++) a[i] = b[i] + c[i]; #pragma omp barrier scale = sum(a, 0, n) + sum(z, 0, n) + f; /** Enf of parallel region **/.5 OpenMP* 6

8 OpenMP* OpenMP* Linux* cat -n pi_omp.c 1 #include <omp.h> 2 static int num_steps = ; double step; 3 void main () 4 5 int i; double x, pi, sum = 0.0; 6 int nthreads; 7 step = 1.0/(double) num_steps; 8 OpenMP* 9 10 nthreads = omp_get_num_threads(); OpenMP* 11 for reduction (+:sum) private(x) 12 for (i=1;i<= num_steps; i++) 13 x = (i-0.5)*step; 14 sum = sum + 4.0/(1.0+x*x); pi = step * sum; 17 printf("%d Threads PI = %f \n",nthreads,pi); 18 $ icc -O3 -openmp _openmp-report2 pi_omp.c pi_omp.c(9) : (col. 1) remark: OpenMP DEFINED REGION WAS PARALLELIZED. pi_omp.c(11) : (col. 1) remark: OpenMP DEFINED LOOP WAS PARALLELIZED. $ setenv OMP_NUM_THREADS 2 $ time./a.out 2 Threads PI = u 0.001s 0: % 0+0k 0+0io 122pf+0w.6 OpenMP* OpenMP* OpenMP* /Qopenmp Windows*-openmp Linux* OpenMP* OpenMP* OpenMP* OpenMP* 7

9 3.3 OpenMP* OpenMP* OpenMP* OpenMP* C/C++ Fortran while for (i=1;i<= n; i++) a[ 1] = = a[ 2] ;

10 4OpenMP* 4.1 OpenMP* #pragma OpenMP* OpenMP* #pragma 1 #pragma omp construct [clause [clause] ] 4.2OpenMP* OpenMP* API OpenMP* call omp_set_num_threads(integer) integer omp_get_num_threads() 1 integer omp_get_max_threads() OMP_NUM_THREADS integer omp_get_thread_num() 0 0 integer omp_get_num_procs() CPU logical omp_in_parallel().false..true. call omp_set_dynamics (logical) logocal omp_get_dynamic() call omp_set_nested(logical) logical omp_get_nested().1 OpenMP* OpenMP* #include omp.h.1 1. clause 9

11 4.3OpenMP* OpenMP* 5 Parallel Regions Worksharing Data Environment Synchronization / Runtime functions/environment variables Parallel Regions Worksharing #pragma omp for #pragma omp sections #pragma omp single Data Environment : threadprivate : sharedprivatelastprivatereductioncopyincopyprivate Synchronization : criticalbarrieratomicflushordermaster / Runtime functions/environment variables 4.4 OpenMP* C/C++ OpenMP* exit() int id = omp_get_thread_num(); more: res(id) = do_big_job(id); if(conv(res(id)) goto more; printf( All done n); if(go_now()) goto more; int id = omp_get_thread_num(); more: res(id) = do_big_job(id); if(conv(res(id)) goto done;? go to more; done: if(!really_done()) goto more;.7 10

12 5. OpenMP* 5.1 parallel OpenMP* Parallel Region for Parallel GOTO C parallel clause OpenMP* OpenMP* Fork-Join Fork [clause[[,]clause]] [clause[[,]clause]] Fork Join Join.8 Fork-Join 11

13 1OpenMP* 2 OpenMP* Fork 3 4 join Fork-Join double A[100]; omp_set_num_threads(4); for for(int i=1;i<100;i++) pooh(i, A); printf(all done n); / A for double A[100]; omp_set_num_threads(4) pooh(i,a) pooh(i,a) pooh(i,a) pooh(i,a) i=1,2,3.. i=26,27,.. i=51,52.. i=76,77.. printf(all done/n);.9 OpenMP* parallel OpenMP* 12

14 main.c #include <omp.h> void main() int num_threads; num_threads = omp_get_num_threads(); printf(" num_threads = %d n",num_threads); whoami (); printf("all Done n"); whoami (); whoami.c / / #include <omp.h> void whoami () int iam; iam = omp_get_thread_num(); #pragma omp critical printf("hello from %d n",iam); / m a i n. c 2 whoami whomai.c.10 OpenMP* main() 2 whoami() whoami() 13

15 5.2 C parallel OpenMP* API 1 for(i=0;i<n;i++) a[i] = a[i] + b[i]; 2OpenMP* private(i,id,istart,iend) id = omp_get_thread_num(); Nthrds = omp_get_num_threads(); istart = id * N / Nthrds; iend = (id+1) * N / Nthrds; for(i=istart;i<iend;i++) a[i]=a[i]+b[i]; 3OpenMP* #pragma omp for schedule(static) for(i=0;i<n;i++) a[i]=a[i]+b[i]; for schedule(static) for(i=0;i<n;i++) a[i]=a[i]+b[i];.11 OpenMP* 1 for 2 OpenMP* 3 for for for #pragma omp for for (I=0;I<N;I++) NEAT_STUFF(I); 14

16 Fork #pragma omp for [clause[[,]clause]] for(int i=0;i<n;i++) for #pragma omp for [clause[[,]clause]] for(int i=0;i<n;i++) for Fork Join Join.12 for OpenMP* double A[100]; omp_set_num_threads(4); for for(int i=1;i<100;i++) pooh(i, A); printf(all done n); / A for double A[100]; omp_set_num_threads(4) pooh(i,a) pooh(i,a) pooh(i,a) pooh(i,a) i=1,2,3.. i=26,27,.. i=51,52.. i=76,77.. printf(all done/n);.13 for 15

17 for schedule #pragma omp for schedule(type[,chunk]) [clause [[,] clause]..] for (I=0;I<N;I++) NEAT_STUFF(I); TYPE STATIC DYNAMIC GUIDED RUNTIME chunk chunk chunk 1 GUIDED chunk chunk chunk 1 type chunk OMP_SCHEDULE OMP_SCHEDULE SCHEDULE(STATIC).2 4 schedule(static,6) 4 schedule(dynamic,3) 4.14 for do while nowait do nowait do schedule(guided,4) 4 16

18 sections sections section #pragma omp sections #pragma omp section #pragma omp section #pragma omp section nowait sections nowait sections section sections section section [clause[[,]clause]] #pragma sections #pragma section #pragma section #pragma section idle idle.15 sections section section 17

19 single single single nowait #pragma omp single [clauses] #pragma omp single idle idle idle idle.16 single single sections section OpenMP* parallel parallel for parallel sections parallel workshare parallel 18

20 5.3 OpenMP* clauseopenmp* OpenMP* parallel do sections workshare single parallel do parallel sections parallel workshape if schedule private share default firstprivate lastprivate copyin copyprivate reduction ordered nowait num_threads.3 OpenMP* SHARED PRIVATE static OpenMP* threadprivate OpenMP* OpenMP* shared OpenMP* private for stack.4 19

21 #include <omp.h> float a[100],b[100]; int stride; main() int i,s,iam,nthreads; nthreads = omp_get_num_threads(); #pragma omp master stride = 100 / nthreads; for private (iam) for ( i = 0; i < nthreads; i++) iam = omp_get_thread_num(); s= iam * stride; f(s); / ab stride tempfrom a,b, stride f(int from) int i; float tmp; for( i=from; i<from+stride; i++ ) tmp = a[i]; a[i] = b[i]; b[i] = tmp; tmp,from a,b, stride tmp,from tmp,from.17 threadprivate master threadprivate threadprivate copyin parallel list private list for private list private Fork 20

22 for OpenMP* private shared (list) OpenMP* shared default (shared private none) default private shared default (private) threadprivate private(list) default (shared) default default (shared) default (none) private shared privatesharedfirstprivatelastprivate reduction privatesharedfirstprivatelastprivate reduction #pragma omp default (private) #pragma firstprivate(i) shared(x) #pragma shared(s) lastprivate(i) firstprivate ( list ) firstprivate private list private private b = 23.0;..... firstprivate(b), private(i,myid) myid = omp_get_thread_num(); for (i=0; i<n; i++) b += c[myid][i]; c[myid][n] = b; 21

23 lastprivate ( list ) private lastprivate private list private section section copyin (list) copyin threadprivate firstprivate copyprivate (list) copyprivate private 22

24 5.4 mastercriticalbarrieratomicflushordered 6 master master #pragma omp master master critical critical #pragma omp critical [(name)] #pragma omp for #pragma omp critical #pragma omp for.18 23

25 barrier #pragma omp barrier atomic atomic #pramga omp atomic Expression-statement 1 x = x op expr, x = expr op x, x = intr (x, expr), x = intr(expr, x) x expr x intr maxminiandiorieor op +,*,-,/,.and.,.or.,.eqv.,.neqv. atomic atomic critical atomic critical #pragma omp for #pragma atomic #pragma omp for.19 atomic 24

26 flush flush #pragma omp flush(list)] list, save shared list,list order order #pragma omp order order for parallel for for order reduction reduction for reduction reduction( op intr : list ) list shared ist intr max miniandiorieor op +,*,-,/,.and.,.or.,.eqv.,.neqv. reduction op reduction nowait reduction barrier 25

27 reduction #include <omp.h> static long num_steps = ; double step; void main () int i; double x, pi, sum = 0.0; step = 1.0/(double) num_steps; for reduction(+:sum) private(x) for (i=1;i<= num_steps; i++) x = (i-0.5)*step; sum = sum + 4.0/(1.0+x*x); pi = step * sum; + 0.or. 0 * 1 max 1-0 min 0.and. 1 // 1.5 reduction reduction reduction #pragma omp for reduction (+:a,y) reduction (.or.:am) 26

28 5.5 if if parallel if TRUE nm_threads nm_threads parallel nowait OpenMP* do sections single nowait #pragma omp for nowait #pragma omp for.19 nowait 27

29 nowait #pragma omp for nowait for( i=from; i<from+stride; i++ ) a[i] = c * b[i]; #pragma omp for nowait for( i=from; i<from+stride; i++ ) x[i] = y[i] * y[i]; 28

30 5.6 / OpenMP* OMP_NUM_THREADS OMP_SCHEDULE OMP_DYNAMIC OMP_NESTED setenv OMP_NUM_THREADS 4Linux set OMP_NUM_THREADS=4Windows type[,chunk] type STATIC/DYNAMIC/GUIDED chunk chunk STATIC 1 STATIC chunk setenv OMP_SCHEDULE "dynamic"linux set OMP_SCHEDULE=dynamicWindows TRUE FALSE setenv OMP_DYNAMIC TRUELinux set OMP_DYNAMIC=TRUEWindows TRUE FALSE FALSE setenv OMP_NESTED TRUELinux set OMP_NESTED=TRUEWindows.6 OpenMP* 29

31 6OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP* OpenMP*.21 OpenMP* OpenMP* 1. VTune 2. OpenMP* 3. MKL OpenMP* 30

32 7. OpenMP* 31

33 HPC IntelIntel PentiumXeonItaniumVTune Intel Corporation * 2006 Intel Corporation J-001 JPN/0603/PDF/SE/DEG/KS

2. OpenMP OpenMP OpenMP OpenMP #pragma#pragma omp #pragma omp parallel #pragma omp single #pragma omp master #pragma omp for #pragma omp critica

2. OpenMP OpenMP OpenMP OpenMP #pragma#pragma omp #pragma omp parallel #pragma omp single #pragma omp master #pragma omp for #pragma omp critica C OpenMP 1. OpenMP OpenMP Architecture Review BoardARB OpenMP OpenMP OpenMP OpenMP OpenMP Version 2.0 Version 2.0 OpenMP Fortran C/C++ C C++ 1997 10 OpenMP Fortran API 1.0 1998 10 OpenMP C/C++ API 1.0