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/* SPDX-License-Identifier: MIT */
/*
* Description: test toggling of iowait on kernels that support it
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "liburing.h"
#include "helpers.h"
static int get_iowait(int cpu)
{
char cpu_buf[32], this_cpu[32];
int user, nice, system, idle, iowait, ret;
FILE *file;
file = fopen("/proc/stat", "r");
if (!file) {
perror("fopen stat");
return 0;
}
sprintf(this_cpu, "cpu%d", cpu);
ret = 0;
do {
int r;
r = fscanf(file, "%s %d %d %d %d %d", cpu_buf, &user, &nice,
&system, &idle, &iowait);
if (r != 6)
continue;
if (strncmp(cpu_buf, this_cpu, strlen(this_cpu)))
continue;
ret = iowait;
break;
} while (1);
fclose(file);
return ret;
}
static int test(struct io_uring *ring, int with_iowait, int cpu)
{
struct io_uring_sqe *sqe;
struct io_uring_cqe *cqe;
int iowait_pre, iowait_post;
struct __kernel_timespec ts;
int ret, fds[2], diff;
char buf[32];
if (!(ring->features & IORING_FEAT_NO_IOWAIT))
return T_EXIT_SKIP;
if (pipe(fds) < 0) {
perror("pipe");
return T_EXIT_FAIL;
}
ret = io_uring_set_iowait(ring, with_iowait);
if (ret) {
fprintf(stderr, "set_iowait=%d\n", ret);
return T_EXIT_FAIL;
}
sqe = io_uring_get_sqe(ring);
io_uring_prep_read(sqe, fds[0], buf, sizeof(buf), 0);
io_uring_submit(ring);
ts.tv_sec = 1;
ts.tv_nsec = 0;
iowait_pre = get_iowait(cpu);
ret = io_uring_wait_cqe_timeout(ring, &cqe, &ts);
if (ret != -ETIME) {
fprintf(stderr, "Unexpected wait ret: %d\n", ret);
return T_EXIT_FAIL;
}
iowait_post = get_iowait(cpu);
diff = iowait_post - iowait_pre;
close(fds[0]);
close(fds[1]);
ret = io_uring_wait_cqe(ring, &cqe);
if (ret) {
fprintf(stderr, "Unexpected wait ret: %d\n", ret);
return T_EXIT_FAIL;
}
io_uring_cqe_seen(ring, cqe);
if (with_iowait) {
if (diff < 90) {
fprintf(stderr, "iowait diff too small: %d\n", diff);
return T_EXIT_FAIL;
}
} else {
if (diff > 10) {
fprintf(stderr, "iowait diff too large: %d\n", diff);
return T_EXIT_FAIL;
}
}
return T_EXIT_PASS;
}
int main(int argc, char *argv[])
{
struct io_uring ring;
cpu_set_t cpuset;
int ret;
CPU_ZERO(&cpuset);
CPU_SET(0, &cpuset);
if (sched_setaffinity(0, sizeof(cpuset), &cpuset))
return T_EXIT_SKIP;
ret = t_create_ring(64, &ring, 0);
if (ret == T_SETUP_SKIP)
return T_EXIT_SKIP;
else if (ret != T_SETUP_OK)
return T_EXIT_FAIL;
ret = test(&ring, 0, 0);
if (ret == T_EXIT_SKIP) {
return T_EXIT_SKIP;
} else if (ret == T_EXIT_FAIL) {
fprintf(stderr, "test 0 failed\n");
return T_EXIT_FAIL;
}
ret = test(&ring, 1, 0);
if (ret == T_EXIT_SKIP) {
return T_EXIT_SKIP;
} else if (ret == T_EXIT_FAIL) {
fprintf(stderr, "test 1 failed\n");
return T_EXIT_FAIL;
}
io_uring_queue_exit(&ring);
return 0;
}
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