[ViewVC] Diff of: cvs/libev/ev

Comparing libev/ev_iouring.c (file contents):
Revision 1.2 by root, Tue Jul 9 00:04:35 2019 UTC vs.
Revision 1.7 by root, Sun Dec 22 15:05:32 2019 UTC

  *    without any syscalls. what's not to like?
  * d) ok, it's vastly more complex, but that's ok, really.
  * e) why 3 mmaps instead of one? one would be more space-efficient,
  *    and I can't see what benefit three would have (other than being
  *    somehow resizable/relocatable, but that's apparently not possible).
+ *    (FIXME: newer kernels can use 2 mmaps only, need to look into this).
  * f) hmm, it's practiclaly undebuggable (gdb can't access the memory, and
-      the bizarre way structure offsets are commuinicated makes it hard to
+ *    the bizarre way structure offsets are communicated makes it hard to
  *    just print the ring buffer heads, even *iff* the memory were visible
  *    in gdb. but then, that's also ok, really.
  * g) well, you cannot specify a timeout when waiting for events. no,
  *    seriously, the interface doesn't support a timeout. never seen _that_
  *    before. sure, you can use a timerfd, but that's another syscall
  *    you could have avoided. overall, this bizarre omission smells
  *    like a µ-optimisation by the io_uring author for his personal
  *    applications, to the detriment of everybody else who just wants
  *    an event loop. but, umm, ok, if that's all, it could be worse.
+ *    (FIXME: jens mentioned timeout commands, need to investigate)
  * h) there is a hardcoded limit of 4096 outstanding events. okay,
  *    at least there is no arbitrary low system-wide limit...
+ *    (FIXME: apparently, this was increased to 32768 in later kernels(
  * i) unlike linux aio, you *can* register more then the limit
  *    of fd events, and the kernel will "gracefully" signal an
  *    overflow, after which you could destroy and recreate the kernel
  *    state, a bit bigger, or fall back to e.g. poll. thats not
  *    totally insane, but kind of questions the point a high
  *    performance I/O framework when it doesn't really work
  *    under stress.
+ *    (FIXME: iouring should no longer drop events, need to investigate)
  * j) but, oh my! is has exactly the same bugs as the linux aio backend,
  *    where some undocumented poll combinations just fail.
  *    so we need epoll AGAIN as a fallback. AGAIN! epoll!! and of course,
  *    this is completely undocumented, have I mantioned this already?
  * k) overall, the *API* itself is, I dare to say, not a total trainwreck.
 /*****************************************************************************/
 static void
 iouring_modify (EV_P_ int fd, int oev, int nev)
 {
-  fprintf (stderr,"modify %d (%d, %d) %d\n", fd, oev,nev, anfds[fd].eflags);//D
   if (ecb_expect_false (anfds [fd].eflags))
     {
       /* we handed this fd over to epoll, so undo this first */
       /* we do it manually because the optimisations on epoll_modify won't do us any good */
       epoll_ctl (iouring_fd, EPOLL_CTL_DEL, fd, 0);
         }
       return;
     }
-  fprintf (stderr, "fd %d event, rearm\n", fd);//D
   /* feed events, we do not expect or handle POLLNVAL */
   fd_event (
     EV_A_
     fd,
     (res & (POLLOUT | POLLERR | POLLHUP) ? EV_WRITE : 0)
 static void
 iouring_poll (EV_P_ ev_tstamp timeout)
 {
   /* if we have events, no need for extra syscalls, but we might have to queue events */
   if (iouring_handle_cq (EV_A))
-    timeout = 0.;
+    timeout = EV_TS_CONST (0.);
   else
     /* no events, so maybe wait for some */
     iouring_tfd_update (EV_A_ timeout);
-  /* only enter the kernel if we have somethign to submit, or we need to wait */
+  /* only enter the kernel if we have something to submit, or we need to wait */
   if (timeout || iouring_to_submit)
     {
       int res;
       EV_RELEASE_CB;
       res = evsys_io_uring_enter (iouring_fd, iouring_to_submit, 1,
-                                  timeout ? IORING_ENTER_GETEVENTS : 0, 0, 0);
+                                  timeout > EV_TS_CONST (0.) ? IORING_ENTER_GETEVENTS : 0, 0, 0);
       iouring_to_submit = 0;
       EV_ACQUIRE_CB;
       if (ecb_expect_false (res < 0))
 iouring_init (EV_P_ int flags)
 {
   if (!epoll_init (EV_A_ 0))
     return 0;
+  iouring_entries     = IOURING_INIT_ENTRIES;
+  iouring_max_entries = 0;
+  if (iouring_internal_init (EV_A) < 0)
+    {
+      iouring_internal_destroy (EV_A);
+      return 0;
+    }
-  ev_io_init  (EV_A_ &iouring_epoll_w, iouring_epoll_cb, backend_fd, EV_READ);
+  ev_io_init  (&iouring_epoll_w, iouring_epoll_cb, backend_fd, EV_READ);
   ev_set_priority (&iouring_epoll_w, EV_MAXPRI);
   ev_io_init  (&iouring_tfd_w, iouring_tfd_cb, iouring_tfd, EV_READ);
   ev_set_priority (&iouring_tfd_w, EV_MAXPRI);
-  iouring_entries     = IOURING_INIT_ENTRIES;
-  iouring_max_entries = 0;
-  if (iouring_internal_init (EV_A) < 0)
-    {
-      iouring_internal_destroy (EV_A);
-      return 0;
-    }
   ev_io_start (EV_A_ &iouring_epoll_w);
   ev_unref (EV_A); /* watcher should not keep loop alive */
   ev_io_start (EV_A_ &iouring_tfd_w);

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Comparing libev/ev_iouring.c (file contents): Revision 1.2 by root, Tue Jul 9 00:04:35 2019 UTC vs. Revision 1.7 by root, Sun Dec 22 15:05:32 2019 UTC

Diff Legend

Comparing libev/ev_iouring.c (file contents):
Revision 1.2 by root, Tue Jul 9 00:04:35 2019 UTC vs.
Revision 1.7 by root, Sun Dec 22 15:05:32 2019 UTC