How to understand the error code when setting worker thread binding CPU to io_uring-register_iowq-aff failed? about liburing HOT 6 CLOSED

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from liburing.

Please just paste your code and the errors into the GitHub issue, I really don't want to download random word documents for something that should just be readily readable in here. Include what kernel you are using as well.

from liburing.

Hi，
I directly simplified the wq aff. c program for testing, and the program is as follows：
#####################################################################
/* SPDX-License-Identifier: MIT /
/

• Description: test that io-wq affinity is correctly set for SQPOLL
  */
  #define _GNU_SOURCE
  #include <stdio.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <stdlib.h>
  #include <string.h>
  #include <liburing.h>
  #include <sched.h>
  // #include "helpers.h"

#define IOWQ_CPU 0
#define SQPOLL_CPU 1

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);
}

if (pipe(fds) < 0) {
	perror("pipe");
}

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);
io_uring_queue_exit(&ring);
return ret;

}

int main(int argc, char *argv[])
{
int ret;
ret = test(1);
return 0;
}

from liburing.

Hi，
The test results are as follows：
[root@localhost wxh]# ./wxh_iouring io_uring.conf
register aff: -22
[root@localhost wxh]# ./wxh_iouring
register aff: -22

from liburing.

Hi,
The kernel version I tested is as follows:
5.10.0-136.12.0.86.oe2203sp1.x86_64

from liburing.

I don't know what version of kernel that is, but if you get -EINVAL, then it's too old to support WQ_AFF. The current 5.10-stable trees do support it, but older ones do not.

from liburing.