strange timeout error returned by kevent() in 6.0

[John-Mark Gurney]

Igor Sysoev wrote this message on Thu, Sep 01, 2005 at 18:26 +0400:
> On Thu, 1 Sep 2005, Igor Sysoev wrote:
> 
> >I found strange timeout errors returned by kevent() in 6.0 using
> >my http server named nginx.  The nginx's run on three machines:
> >two 4.10-RELEASE and one 6.0-BETA3.  All machines serve the same
> >content (simple cluster) and each handles about 200 requests/second.
> >
> >On 6.0 sometimes (2 or 3 times per hour) in the daytime kevent()
> >returns EV_EOF in flags and ETIMEDOUT in fflags, nevertheless:
> >
> >1) nginx does not set any kernel timeout for sockets;
> >2) the total request time for such failed requests is small, 30 and so 
> >seconds.
> 
> I have changed code to ignore the ETIMEDOUT error returned by kevent()
> and found that subsequent sendfile() returned the ENOTCONN.
> 
> By the way, why sendfile() may return ENOTCONN ?
> I saw this error code on 4.x too.

The reason that you are seeing ETIMEDOUT/ENOTCONN is that the connection
probably ETIMEDOUT (aka timed out)... and so is ENOTCONN (no longer
connected).. can you also do a read or a write to the socket successfully?

and sendfile(3) says:
ERRORS
	[...]

     [ENOTCONN]         The s argument points to an unconnected socket.

and a glance at tcp(4) says:
ERRORS
	[...]

     [ETIMEDOUT]        when a connection was dropped due to excessive
                        retransmissions;

There's the answers...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."