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// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <unistd.h>
#include "../tests.h"
static int loops = 100;
static char buf;
int context_switch_loop_work = 1234;
#define write_block(fd) \
do { \
if (write(fd, &buf, 1) <= 0) \
return 1; \
} while (0)
#define read_block(fd) \
do { \
if (read(fd, &buf, 1) <= 0) \
return 1; \
} while (0)
/* Not static to avoid LTO clobbering the function name */
int context_switch_loop_proc1(int in_fd, int out_fd);
int context_switch_loop_proc1(int in_fd, int out_fd)
{
for (int i = 0; i < loops; i++) {
read_block(in_fd);
context_switch_loop_work += i * 3;
write_block(out_fd);
}
return 0;
}
int context_switch_loop_proc2(int in_fd, int out_fd);
int context_switch_loop_proc2(int in_fd, int out_fd)
{
for (int i = 0; i < loops; i++) {
write_block(out_fd);
context_switch_loop_work += i * 7;
read_block(in_fd);
}
return 0;
}
/*
* Launches two processes that take turns to execute a multiplication N times
*/
static int context_switch_loop(int argc, const char **argv)
{
int a_to_b[2], b_to_a[2];
pid_t proc1_pid;
int status;
int ret;
if (argc > 0) {
loops = atoi(argv[0]);
if (loops < 0) {
fprintf(stderr, "Invalid number of loops: %s\n", argv[0]);
return 1;
}
}
if (pipe(a_to_b) || pipe(b_to_a)) {
perror("Pipe error");
return 1;
}
proc1_pid = fork();
if (proc1_pid < 0) {
perror("Fork error");
return 1;
}
if (!proc1_pid) {
close(a_to_b[0]);
close(b_to_a[1]);
prctl(PR_SET_NAME, "proc1", 0, 0, 0);
ret = context_switch_loop_proc1(b_to_a[0], a_to_b[1]);
close(a_to_b[1]);
close(b_to_a[0]);
exit(ret);
}
close(a_to_b[1]);
close(b_to_a[0]);
prctl(PR_SET_NAME, "proc2", 0, 0, 0);
ret = context_switch_loop_proc2(a_to_b[0], b_to_a[1]);
close(a_to_b[0]);
close(b_to_a[1]);
if (ret) {
kill(proc1_pid, SIGKILL);
return ret;
}
if (waitpid(proc1_pid, &status, 0) != proc1_pid || !WIFEXITED(status) ||
WEXITSTATUS(status))
return 1;
return 0;
}
DEFINE_WORKLOAD(context_switch_loop);
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