[Serusers] Performance tuning

[Andrei Pelinescu-Onciul]

On Mar 23, 2004 at 23:04, zeusng <zeus.ng at isquare.com.au> wrote:
[...]
> 
> As for your explanation of EAGAIN on linux, I do recall a different version
> on some of the other discussion group. It talks about short of resource.
> Also the man page shows a different story.

I've just looked again over the kernel sources and I can't see any other
possibility.
> 
> EAGAIN         The  socket is marked non-blocking and the receive
>                operation would block, or a  receive  timeout  had
>                been  set  and the timeout expired before data was
>                received.
> I'm not saying you are wrong, but that's not what I perceived.

The manual page has the POSIX interpretation on EAGAIN. In linux however
there is this exception: socket in blocking mode, wait for receive and
udp with bad checksum.
Check net/ipv4/udp.c in your kernel sources. The function name is
udp_recvmsg.
> 
> The tuning parameter I did was based on a previous experience on another
> application, namely SAP. It had a similar problem until I made the changes.
> I must admit that I also change /proc/sys/fs/file-max and some other
> variables as well.
> 
> One more interesting thing I observed during the stress test. If I have a
> lot of REGISTERs  (say thousand) expire at around the same time, SER would
> not process any new requests until all expired REGISTERs were gone. Any
> explanation on this?
> 

Andrei