1// RUN: %libomp-compile
2// RUN: %libomp-run
3// RUN: env KMP_AFFINITY=none %libomp-run
4// REQUIRES: linux
5
6// Check if forked child process resets affinity properly by restricting
7// child's affinity to a subset of the parent and then checking it after
8// a parallel region
9
10#define _GNU_SOURCE
11#include "libomp_test_affinity.h"
12#include <omp.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <sys/wait.h>
16#include <sys/types.h>
17#include <unistd.h>
18
19// Set the affinity mask of the calling thread to a proper subset of the
20// original affinity mask, specifically, one processor less.
21void set_subset_affinity(affinity_mask_t *mask) {
22 int cpu;
23 affinity_mask_t *original_mask = affinity_mask_alloc();
24 affinity_mask_copy(dest: original_mask, src: mask);
25 // Find first processor to clear for subset mask
26 for (cpu = 0; cpu <= AFFINITY_MAX_CPUS; ++cpu) {
27 if (affinity_mask_isset(mask: original_mask, cpu)) {
28 affinity_mask_clr(mask, cpu);
29 break;
30 }
31 }
32 affinity_mask_free(mask: original_mask);
33 set_thread_affinity(mask);
34}
35
36int main(int argc, char **argv) {
37 char buf[1024] = {0};
38 char *other_buf;
39 size_t n;
40 int child_exit_status, exit_status;
41 affinity_mask_t *mask = affinity_mask_alloc();
42 get_thread_affinity(mask);
43 n = affinity_mask_snprintf(buf, bufsize: sizeof(buf), mask);
44 printf(format: "Orignal Mask: %s\n", buf);
45
46 if (affinity_mask_count(mask) == 1) {
47 printf(format: "Only one processor in affinity mask, skipping test.\n");
48 exit(EXIT_SUCCESS);
49 }
50
51 #pragma omp parallel
52 {
53 #pragma omp single
54 printf(format: "Hello! Thread %d executed single region in parent process\n",
55 omp_get_thread_num());
56 }
57
58 pid_t pid = fork();
59 if (pid < 0) {
60 perror(s: "fork()");
61 exit(EXIT_FAILURE);
62 }
63
64 if (pid == 0) {
65 // Let child set a new initial mask
66 set_subset_affinity(mask);
67 #pragma omp parallel
68 {
69 #pragma omp single
70 printf(format: "Hello! Thread %d executed single region in child process\n",
71 omp_get_thread_num());
72 }
73 affinity_mask_t *new_mask = affinity_mask_alloc();
74 get_thread_affinity(mask: new_mask);
75 if (!affinity_mask_equal(mask1: mask, mask2: new_mask)) {
76 affinity_mask_snprintf(buf, bufsize: sizeof(buf), mask);
77 fprintf(stderr, format: "Original Mask = %s\n", buf);
78 affinity_mask_snprintf(buf, bufsize: sizeof(buf), mask: new_mask);
79 fprintf(stderr, format: "New Mask = %s\n", buf);
80 affinity_mask_free(mask: new_mask);
81 fprintf(stderr, format: "Child affinity mask did not reset properly\n");
82 exit(EXIT_FAILURE);
83 }
84 affinity_mask_free(mask: new_mask);
85 exit_status = EXIT_SUCCESS;
86 } else {
87 pid_t child_pid = pid;
88 pid = wait(stat_loc: &child_exit_status);
89 if (pid == -1) {
90 perror(s: "wait()");
91 exit(EXIT_FAILURE);
92 }
93 if (WIFEXITED(child_exit_status)) {
94 exit_status = WEXITSTATUS(child_exit_status);
95 } else {
96 exit_status = EXIT_FAILURE;
97 }
98 }
99
100 affinity_mask_free(mask);
101 return exit_status;
102}
103

source code of openmp/runtime/test/affinity/redetect.c