test/wq-aff: add test case for SQPOLL io-wq affinity

Signed-off-by: Jens Axboe <[email protected]>

test/Makefile

@@ -195,6 +195,7 @@ test_srcs := \
 	unlink.c \
 	version.c \
 	wakeup-hang.c \
+	wq-aff.c \
 	xattr.c \
 	# EOL
 

test/wq-aff.c

@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test that io-wq affinity is correctly set for SQPOLL
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "liburing.h"
+#include "helpers.h"
+
+#define IOWQ_CPU	0
+#define SQPOLL_CPU	1
+
+static int verify_comm(pid_t pid, const char *name, int cpu)
+{
+	char comm[64], buf[64];
+	cpu_set_t set;
+	int fd, ret;
+
+	sprintf(comm, "/proc/%d/comm", pid);
+	fd = open(comm, O_RDONLY);
+	if (fd < 0) {
+		perror("open");
+		return T_EXIT_SKIP;
+	}
+
+	ret = read(fd, buf, sizeof(buf));
+	if (ret < 0) {
+		close(fd);
+		return T_EXIT_SKIP;
+	}
+
+	if (strncmp(buf, name, strlen(name) - 1)) {
+		close(fd);
+		return T_EXIT_SKIP;
+	}
+
+	close(fd);
+
+	ret = sched_getaffinity(pid, sizeof(set), &set);
+	if (ret < 0) {
+		perror("sched_getaffinity");
+		return T_EXIT_SKIP;
+	}
+
+	if (CPU_COUNT(&set) != 1) {
+		fprintf(stderr, "More than one CPU set in mask\n");
+		return T_EXIT_FAIL;
+	}
+	if (!CPU_ISSET(cpu, &set)) {
+		fprintf(stderr, "Wrong CPU set in mask\n");
+		return T_EXIT_FAIL;
+	}
+
+	return T_EXIT_PASS;
+}
+
+static int verify_affinity(pid_t pid, int sqpoll)
+{
+	pid_t wq_pid, sqpoll_pid = -1;
+	char name[64];
+	int ret;
+
+	wq_pid = pid + 2;
+	if (sqpoll)
+		sqpoll_pid = pid + 1;
+
+	/* verify we had the pids right */
+	sprintf(name, "iou-wrk-%d", pid);
+	ret = verify_comm(wq_pid, name, IOWQ_CPU);
+	if (ret != T_EXIT_PASS)
+		return ret;
+
+	if (sqpoll_pid != -1) {
+		sprintf(name, "iou-sqp-%d", pid);
+		ret = verify_comm(sqpoll_pid, name, SQPOLL_CPU);
+		if (ret != T_EXIT_PASS)
+			return ret;
+	}
+
+	return T_EXIT_PASS;
+}
+
+static int test(int sqpoll)
+{
+	struct io_uring_params p = { };
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	char buf[64];
+	int fds[2], ret;
+	cpu_set_t set;
+
+	if (sqpoll) {
+		p.flags = IORING_SETUP_SQPOLL | IORING_SETUP_SQ_AFF;
+		p.sq_thread_cpu = SQPOLL_CPU;
+	}
+
+	io_uring_queue_init_params(8, &ring, &p);
+
+	CPU_ZERO(&set);
+	CPU_SET(IOWQ_CPU, &set);
+
+	ret = io_uring_register_iowq_aff(&ring, sizeof(set), &set);
+	if (ret) {
+		fprintf(stderr, "register aff: %d\n", ret);
+		return T_EXIT_FAIL;
+	}
+
+	if (pipe(fds) < 0) {
+		perror("pipe");
+		return T_EXIT_FAIL;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_read(sqe, fds[0], buf, sizeof(buf), 0);
+	sqe->flags |= IOSQE_ASYNC;
+
+	io_uring_submit(&ring);
+
+	usleep(10000);
+
+	ret = verify_affinity(getpid(), sqpoll);
+	io_uring_queue_exit(&ring);
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	if (argc > 1)
+		return T_EXIT_SKIP;
+
+	ret = test(1);
+	if (ret) {
+		fprintf(stderr, "test sqpoll failed\n");
+		return T_EXIT_FAIL;
+	}
+
+	return T_EXIT_PASS;
+}