Hi.
Thank you for your answer!
Following your advice, I've made a little iterative testing program, and the
results are strange. First I tried to send repeatedly large *int* arrays, up
to 100MB (yes, MB!) and it worked perfectly. Out of 50, not even one was
lost! However, when I tried to perform the same iterative test using the
objects I'm working with in real condition, it failed.
The application I'm working on exchanges custom objects (called *
RasterAdapter*) designed to encapsulate *java.awt.image.Raster* and make
them *Serializable*. Thus, a *RasterAdapter* uses custom *writeObject()* and
*readObject()* methods (which work, I'm absolutely sure of this). The fact
is when I send repeatedly such *RasterAdapter*s, it works until 1100KB
(approximately, it's hard for me to control precisely the size of these
objects) and when the objects exceed this weigh, they get lost.
By "they get lost", I mean they don't reach their destination. Indeed they
transit through FishFarm, not directly Shoal and the issue may be totally
independent from Shoal. But as FishFarm is supposed to just serialize the
objects, send them as Shoal messages and unserialize them on the other side,
I'm surprized... it works with *int* arrays but with my objects the
unserialization is never performed, as if the message had been lost or
corrupted... I've already got in touch with FishFarm's author, who told me
he was using Shoal with the default configuration.
The output shows no particular message, and no log file is produced. I'm
ashamed as I didn't figure out how to enable logging in Shoal (or JXTA),
it's probably very simple but I didn't find anything...
Thank you for JXTA's programmatic configuration Api, I'll look at it.
Nevertheless I think you're right, as Shoal uses TCP channels I won't be
able to tune anything, and multicast confiuration probably won't change
anything either...
Anyway I thank you very much for your answer, and I apologize in the case
the problem doesn't come from Shoal, which is very probable.
Regards,
Mathias CHOUET
2008/8/6 Shreedhar Ganapathy <Shreedhar.Ganapathy_at_sun.com>
> Hi Mathias
> Thanks for posting here. Its certainly good to know about your usage of
> Fishfarm and indirectly, Shoal.
>
> A few questions:
> A few iterative trials might establish where the issue lies. Could you try
> with packet sizes lower than 64KB i.e say 10KB through to 60 KB and then go
> beyond ? That would indicate where possible bottlenecks could be. Would be
> even better if this could be profiled.
>
> Are you seeing any exceptions or messages in the log output to suggest
> failure to send messages? Could you share the logs here?
>
> We can surely look into exposing properties that can be set in Jxta.
> Jxta provides a programmatic Api for configurations called
> NetworkConfigurator.
>
> https://jxta-jxse.dev.java.net/source/browse/jxta-jxse/trunk/api/src/net/jxta/platform/NetworkConfigurator.java?rev=555&view=markup
>
> However it does not expose anything related to tuning TCP presumably
> because the underlying OS level TCP protocol implementation is expected to
> provide flow control, fragmentation support, etc. There could be opportunity
> for some RFEs there.
>
> I can see an api for setting the Multicast packet size but in this case you
> report it may not be relevant as Shoal uses the TCP channel to send
> messages.
>
> hth
> Shreedhar