Re: [eclipse-clp-users] Eclipse-Java communication times

On 05/09/2010 20:39, Daniel Riera wrote:
> Dear all,
>
> does anybody know if there exists any study or experimental data on
> the time spent in calls and answers
> between Java programs and eclipse ones?
>
> Thank you very much,
> Daniel

Hi Daniel,

I am nor sure what exactly you are after, do you mean the overheads in 
communication between ECLiPSe and Java when using the Java interface for 
ECLiPSe? In this case, there are different cases, depending on how your 
Java is connected to ECLiPSe -- EmbeddedEclipse, OutOfProcessEclipse, or 
RemoteEclipse.

With OutOfProcessEclipse and RemoteEclipse, the I/O queues used for 
communicating between ECLiPSe and Java are implemented on top of 
sockets. I have done some timing studies when we first developed the 
Tcl/Tk version of the interface, and the results should apply to Java as 
well. In this case, there seems to be a relatively significant overhead 
in sending any data between ECLiPSe and Java, but there is a much 
smaller dependency on the data size being sent. I can't remember the 
exact figures, but I would expect the overhead of setting up each 
communication to take perhaps tens of milliseconds or more, but once you 
established the connection, the additional times to send several bytes 
or many kilobytes of data will be similar (and much less than the setup 
overheads). I think this was for ECLiPSe and Tcl (i.e. equivalent to 
Java) being on the same machine, i.e. the equivalent of 
OutOfProcessEclipse. For ECLiPSe and Java on different machines, then 
you need to take into account sending the data through whatever network 
connections is between your machines.

In summary, it is quite expensive to send data between Java and ECLiPSe 
for OutofProcess and Remote Eclipse, and you should try to do this as 
little as possible, and try to send as much data each time as possible.

For EmbeddedEclipse, the data queues are implemented in the process' 
memory, so there should be no setup overhead, and the cost of 
writing/reading the data should also be much lower.

Cheers,

Kish

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