[omniORB] Bad performance with oneway invocation

[Serguei Kolos]

Hello

I'm evaluating now two ORBs: TAO and omniORB, making comparison of their
functionality and performance. I wrote a simple IDL file:
    interface Echo
    {
        oneway void     oneway_echo();
        void            twoway_echo();
    };
and implemented server and client applications in both TAO1.3 and 
omniORB 4.0.1.
The server creates one object and prints out it's IOR, the client takes 
this IOR and
then in a loop makes 100000 remote invocations of requested type and 
calculates mean
time for a single invocation.

Doing the tests I obtained the following results:
1. The normal (two-way) invocation round-trip time is about 40% better 
with the omniORB
    (the time is ~420 us for TAO and ~260 us for the omniORB).
2. The asynchronous (oneway) round-trip time is from 3 to 10 times worse 
with the omniORB.
    Let me explain: Using the default configuration I got ~60 us time 
per invocation with TAO
    and ~600 us per invocation for the omniORB.
    I have found immediately that this huge time in omniORB produced by 
a large number of threads,
    which the server starts to process asynch requests coming over 
single connection. I set then
    the maxServerThreadPerConnection to 1 and then get only one thread 
processing all the
    requests and obtained ~160 us time per invocation (which is already 
much better then before, but
    still much worse then with TAO).
   
What is also interesting is that:
    1. If I use the omniORB client with the TAO server the time is even 
better - ~35 us
    2. If I use the TAO client with the omniORB server the time is again 
bad - ~180 us.

If I'm not doing anything particularly stupid, then there is an issue 
for the oneway methods
in the omniORB. Can this issue be resolved with the proper configuration 
of the omniORB server
or with the next omniORB release?

Thanks
Sergei

PS: I was running my tests on two Linux boxes (RedHat 7.3 kernel 2.4.20) 
with gcc 3.2.
The boxes are dual pentium 1GHz with 512 Mb. Server and client always 
run on different
machines.