mirror of
https://github.com/OpenMP/Examples.git
synced 2025-04-04 05:41:33 +01:00
90 lines
2.5 KiB
C
90 lines
2.5 KiB
C
/*
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* @@name: affinity_display.3.c
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* @@type: C
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* @@compilable: yes
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* @@linkable: yes
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* @@expect: success
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* @@version: omp_5.0
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*/
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#include <stdio.h>
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#include <stdlib.h> // also null is in <stddef.h>
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#include <stddef.h>
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#include <string.h>
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#include <omp.h>
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#define FORMAT_STORE 80
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#define BUFFER_STORE 80
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int main(void){
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int i, n, thrd_num, max_req_store;
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size_t nchars;
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char default_format[FORMAT_STORE];
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char my_format[] = "host=%20H thrd_num=%0.4n binds_to=%A";
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char **buffer;
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// CODE SEGMENT 1 AFFINITY FORMAT
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// Get and Display Default Affinity Format
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nchars = omp_get_affinity_format(default_format,(size_t)FORMAT_STORE);
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printf("Default Affinity Format is: %s\n",default_format);
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if(nchars >= FORMAT_STORE){
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printf("Caution: Reported Format is truncated. Increase\n");
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printf(" FORMAT_STORE to %d.\n", nchars+1);
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}
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// Set Affinity Format
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omp_set_affinity_format(my_format);
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printf("Affinity Format set to: %s\n",my_format);
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// CODE SEGMENT 2 CAPTURE AFFINITY
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// Set up buffer for affinity of n threads
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n = omp_get_num_procs();
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buffer = (char **)malloc( sizeof(char *) * n );
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for(i=0;i<n;i++){ buffer[i]=(char *)malloc( sizeof(char) * BUFFER_STORE); }
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// Capture Affinity using Affinity Format set above.
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// Use max reduction to check size of buffer areas
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max_req_store = 0;
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#pragma omp parallel private(thrd_num,nchars) reduction(max:max_req_store)
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{
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if(omp_get_num_threads()>n) exit(1); //safety: don't exceed # of buffers
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thrd_num=omp_get_thread_num();
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nchars=omp_capture_affinity(buffer[thrd_num],(size_t)BUFFER_STORE,NULL);
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if(nchars > max_req_store) max_req_store=nchars;
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// ...
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}
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for(i=0;i<n;i++){
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printf("thrd_num= %d, affinity: %s\n", i,buffer[i]);
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}
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// For 4 threads with OMP_PLACES='{0,1},{2,3},{4,5},{6,7}'
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// Format host=%20H thrd_num=%0.4n binds_to=%A
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// affinity: host=hpc.cn567 thrd_num=0000 binds_to=0,1
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// affinity: host=hpc.cn567 thrd_num=0001 binds_to=2,3
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// affinity: host=hpc.cn567 thrd_num=0002 binds_to=4,5
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// affinity: host=hpc.cn567 thrd_num=0003 binds_to=6,7
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if(max_req_store>=BUFFER_STORE){
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printf("Caution: Affinity string truncated. Increase\n");
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printf(" BUFFER_STORE to %d\n",max_req_store+1);
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}
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for(i=0;i<n;i++) free(buffer[i]);
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free (buffer);
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return 0;
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}
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