public inbox for [email protected]
 help / color / mirror / Atom feed
From: William Dauchy <[email protected]>
To: [email protected]
Subject: io_uring_peek_cqe and EAGAIN
Date: Mon, 20 Apr 2020 18:27:48 +0200	[thread overview]
Message-ID: <20200420162748.GA43918@dontpanic> (raw)

Hello,

While doing some tests which are open/read/close files I saw that I
was getting -EAGAIN return value sometimesi on io_uring_peek_cqe,
and more often after dropping caches.
In parrallel, when reading examples provided by liburing, we can see
that getting this error is making the example fail (such as in
io_uring-cp). So I was wondering whether it was stupid to change the
example to something like:

diff --git a/examples/io_uring-cp.c b/examples/io_uring-cp.c
index cc7a227..2d6d190 100644
--- a/examples/io_uring-cp.c
+++ b/examples/io_uring-cp.c
@@ -170,11 +170,11 @@ static int copy_file(struct io_uring *ring, off_t insize)
     ret = io_uring_wait_cqe(ring, &cqe);
     got_comp = 1;
    } else {
-    ret = io_uring_peek_cqe(ring, &cqe);
-    if (ret == -EAGAIN) {
-     cqe = NULL;
-     ret = 0;
-    }
+    do {
+     ret = io_uring_peek_cqe(ring, &cqe)
+     if (ret != -EAGAIN)
+      break;
+    } while (1);
    }
    if (ret < 0) {
     fprintf(stderr, "io_uring_peek_cqe: %s\n",


Best,
-- 
William

             reply	other threads:[~2020-04-20 16:28 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 16:27 William Dauchy [this message]
2020-04-22 20:57 ` io_uring_peek_cqe and EAGAIN Jens Axboe
2020-04-23 14:42   ` William Dauchy
2020-04-23 15:05     ` Jens Axboe
2020-04-23 15:12       ` William Dauchy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200420162748.GA43918@dontpanic \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox